BIOLOGY LIBRARY ILLUSTRATIONS VEGETABLE PHYSIOLOGY. ILLUSTRATES V, VEGETABLE PHYSIOLOGY, PRACTICALLY APPLIED, THE CULTIVATION OF THE GARDEN, THE FIELD, AND THE FOREST; CONSISTING OP ORIGINAL OBSERVATIONS, COLLECTED DURING AN EXPERIENCE OF FIFTY YEARS. BY JAMES MAIN, A. L. S. rt,-i<>-i> Florist's Directory," " Popular Botany, "Sec. tants LONDON: ORR AND SMITH, PATERNOSTER-ROW. MDCCCXXXV. / VUf BIOLOGY LIBRARY G mtAUBURY AND EVANS, WHI i KK (LATE T. DAVISON. ) TO J. E. BICHENO, F. R. L. G. & Z. Soc. AS AN ADMIRER OK NATURE AND NATURAL PHILOSOPHY. CONVERSANT WITH THE SUBJECT TREATED OF IN THE FOLLOWING PAGES AN ENCOURAGER OF EVERY BRANCH OF RATIONAL SCIENCE, AND, ABOVE ALL, ACTUATED BY THE MOST LIBERAL AND UNBIASSED PRINCIPLES RELATIVE TO WHATEVER HAS, BEEN OR MAY BE PROPOUNDED ON SUBJECTS OF NATURAL HISTORY, QEfyig Volume IS RESPECTFULLY DEDICATED, BY HIS MOST OBEDIENT AND OBLIGED SERVANT, JAMES MAIN, CONTENTS. Vegetation, Elements and Structure Organisation Vegetable Life PACK. 1 8 14 Distinctions of Vegetables .... 23 Acotyledoncac .... . 27 Monocotyledonea* 33 61 Organic Structure of Dicotyledonous Plants 85 Sap ........ . 114 Seat of Vegetable Life 132 Origin of Buds ...... . 144 Appendages of the Stem .... 149 Causes of Barrenness ..... . 162 Application of Physiological Knowledge 175 Sowing ..... . ibid. Transplanting .... 191 Propagation ..... . 202 222 Training: 254 viii CONTENTS. PAGE. Cross Impregnation 263 Vegetable Food . 271 Diseases of Vegetables 279 Insects destructive to Plants 290 Felling Timber ....... 307 Grubbing 315 Longevity of Trees . . . 317 Conclusion ... .... 320 PREFACE. NOTWITHSTANDING Vegetable Physiology has engaged the attention of some of the most dis- tinguished Naturalists in Europe, it is still but imperfectly understood. The highest authorities are not yet agreed on the subject, differing in in opinion, as well concerning the motions of the fluids, as in respect of the manner of accretion of what may be called the solids of plants. Hitherto the science has been in some degree obscured by the terms employed in its illustra- tion. It has been explained too frequently by references to animal anatomy ; and because there are resemblances in some particulars, a too general idea has been entertained, that the whole of the X PREFACE. one might be understood by reference to the other. This has tended to check investigation, by withdrawing the attention of the student from the phenomena, and inducing him to be satisfied with vague assertion rather than actual proof. But as mere fictitious knowledge cannot be useful, it is necessary, especially for young prac- titioners, that the science should be divested, if possible, of some of its superfluous disguise, and treated of in such language as shall be equal to every capacity. Under these impressions the following pages have been written, and in tended to bear a popular rather than a scientific character, with the sole view of assisting, by familiar explanation, the various practice of the gardener and woodman. In fact, the principal feature of the book is an attempt to explain only what has been obscurely or too learnedly treated before ; to mention cir- cumstances which, though generally known, have never appeared in print; and to make up for deficient language by explanatory figures of the visible constituents of plants: the intention being, PREFACE. XI however, only to mark the greater parts, their limits, and their connections, leaving the minor and less striking portions of vegetable structure to those who may have better opportunities to examine and describe them. On this plan the work will be found a com- pendium of the discoveries and best authenticated facts which have appeared in the writings of others, and which have been proved in the prac- tice and experience of the writer, or in that of his cotemporaries, during the last fifty years. He trusts that new matter enough will be found to justify the publication; and though but a rough sketch, which from his very limited know- ledge of chemistry he has not been able to fill up as he wished, still he entertains a hope that, such as it is, it may receive amplification from an abler pen, and accomplish his aim of rendering vegetable physiology better and more generally understood. As many of the ideas in the first essays are detailed without proofs, the latter will be found Xll PREFACE. in the sections which follow, and where they are practically applied. Relative to the arrangement of the book, and the style in which it is written, the author feels it necessary to apologise to the reader for much reiteration. It has been his study to use the plainest language, as most natural to himself and best suited to those for whom he presumes to write. The major part of the essays have been long in manuscript ; additions and interlineations having been made from time to time, as new or more correct ideas occurred. This manner of compilation has occasioned a want of connection, which could not be remedied without the exercise of a talent which the author does not sufficiently possess. He hopes, however, that such will not be considered a blemish ; and trusts that in those instances where he differs most from the opinions of others, he has shown good reasons for so doing, and without expressing himself so dogma- tically as to weaken the force of his represen- tations. PREFACE. Xlll To his botanical friends, A. H. Haworth, Esq. ; Mr. Anderson, Curator of the Physic Garden, Chelsea ; and to Mr. Don, Librarian of the Lin- naean Society of London, he returns his best thanks, for the readiness with which these gentle- men severally answered every question proposed to them on the subject. The figures, chiefly outlines, have been drawn by E. D. Smith, F. L. S., from nature, in all cases when necessary ; some of them are ideally extended, but not without a close imitation of the structure shown by the microscope. Superior execution has not been aimed at, because an accurate outline gives as perfect an idea as the most finished drawings, especially of such parts as are invisible to the naked eye ; neither have these figures been too much multiplied, because this would have been adding expense without any real value. In fact the brevity intended did not allow of much extraneous matter. ILLUSTRATIONS ERRATA. Page 29, top line, read " of the common." - 34, seventh from bottom, for " evolves," read " involves." 49, in the reference to Fig. 18, read " the following spring." 82, thirteenth line, for " back," read " bark." t- 94, fourth line above note, read " Tectonia." - 193, twelfth line from top, for " outlets," read " rootlets." 211, third line from top, for " on," read " in." ~ 221, bottom line, for " and are," read " which expedient is." indirectly, to all that live. Vegetables are organised beings endowed with mo~ lability, which is called life, but without sensation, unless their powers of contractility and irritability may be so deemed. They are formed of elements fitted for expansion recipients of nutrition labora- tories of divers qualities capable of reproduction and at last dissolvable into their first principles. ILLUSTRATIONS VEGETABLE PHYSIOLOGY. L VEGETATION, VEGETABLE ELEMENTS AND STRUCTURE. THE vegetable kingdom is one of the grand divi- sions of nature ; without this animals would have been created in vain ; the vast masses of minerals would have appeared a cheerless waste, had not plants sprung forth to clothe and embellish the earth, yield- ing food and raiment, shade and shelter, directly or indirectly, to all that live. Vegetables are organised beings endowed with mo- tability, which is called life, but without sensation, unless their powers of contractility and irritability may be so deemed. They are formed of elements fitted for expansion recipients of nutrition labora- tories of divers qualities capable of reproduction and at last dissolvable into their first principles. B 2: VEGETABLE PHYSIOLOGY. Fixed to the soil they are expanded either therein,, or in the air or water. The tribes of trees and herbs which eover the face of the earth, though more varied in form and colour, are scarcely more nume- rous than the JPuci* which inhabit the shores and depths of the ocean. Vegetables are said to perform an important office in the scheme of creation, in maintaining an equili- brium among the constituents of the atmosphere, by which its salubrity is improved for the purposes of animal life. In describing the elementary matter or membrane of vegetables, it will not be necessary to notice its various disposition as presented to us by the micro- scope, in the different stages of its advancement from primitive indistinctness to its perfect form in the organisation : suffice it to notice in this place, that it is not a homogeneous solid, but an areolated mass, composed of innumerable vesicles arranged in different forms : either extended into filaments and fibres spread out into tissues depressed into horizontal layers compressed into perpendicular partitions or disposed in regular columns. Vegetable element is said to be composed of oxygen, hydrogen, carbon, and some other bodies detectible by chemical analysis. This combination 0f immaterial bodies, forming a visible and tangible substance, is of itself a mysterious circumstance ; but when we see that the most concrete and durable * Son-weed?,. VEGETABLE PHYSIOLOGY. 3 of vegetable products is capable of complete disso- lution, without any notable residuum, we are con- strained to admit that the conclusion of the chemist is just. When the elemental membrane is uniform in con- sistence and arrangement, it is called cellular ; when varied by being- disposed into tubes and other organs, it is said to be vascular. The microscope has assisted us to discover the constitutional fabric of the cellular matter. Each cell is an insulated vesicle, having a thin, pellucid, elastic integument ; originally inconceivably minute, but capable of being distended to a limited size, but in a definite order incident to the plant to which it belongs, and in any direction ; the cells leaning and super-posed on each other, and consequently pressed into the various figures of spheres, spheroids, hexa- gons, or elongated squares or ovals forming the specific structure and organs of the plant. There are also intercellular spaces, which serve for the con- duction of fluids, or depositories of the secretions of the plant. A microscope of sufficient magnifying power has too confined a field of view to take in any considera- ble portion of cellular matter, to allow of its being accurately represented by the engraver. Sections, in whatever direction made, never show a regular dis- position of the cells, because they, being of irregular form, and irregularly placed with respect to each other, present, when incised, different forms to the 4 VEGETABLE PHYSIOLOGY. eye. This will be easily conceived by looking at a slice of common sponge ; but the annexed sketches will assist to give a better idea of its structure than any language which it is in the writer's power to employ. Of course they are drawn highly magni- fied for the sake of distinctness. The sketch, Fig. 1, represents cellular matter as it appears when expanded perpendicularly, as in the pith, in the leaf-stalks of herbs, and in other parts of plants. Fig. 1. s Fig. 2 shows it as swelling laterally, from right to left, as in the concentric layers of wood. Fig. 2. In the crown of an Agaricus* it appears depressed, as at Fig. 3. f Mushroom. VEGETABLE PHYSIOLOGY. Fig. 3. And Fig. 4, compressed into dense plates, as found in the medullary rays, and other parts of the stem, flowers, and fruit. Fig. 4. The cellular body appears to have no determinate limits, on which account it has been supposed to be self-productive : it continues to increase and pro- trude in every direction, if any vacancy is to be filled up, or any part of the organisation to be com- pleted. The organs are all formed of it, and it is the material that unites them together. The exterior of a cellular body, when exposed to the air, is always condensed into cuticle or bark ; and from this effect, viz. the hardening action of the sun and air, we invariably see it, in the act of expansion, descending with more rapidity than increasing in any other direction. This circumstance is exemplified by the upper side 6 VEGETABLE PHYSIOLOGY. of a wound on the stem of a tree healing over more rapidly than the other sides; by the under sides of horizontal stems or branches being farther extended from the pith than the upper ; and by any deformity on a stem increasing downward faster than in any other direction. The pellicles of the cells are of various consistence and properties as to durability. In the lower orders of cellular es> as Fungi* for instance, they are muci- laginous and fugitive ; in the higher orders of vascu- lares they become ligneous ; and, along with the secreted juices of the plant, constitute what is called timber. Such plants as are wholly formed of cellular matter, gain magnitude by a uniform swelling motion from the centre outwards, Fig. 5. This Fig. 5. progressive growth is continued for a longer or shorter time according as the exciting circum- stances are more or less favourable. A Boletus f may be increased from a mere speck to a disk of two feet in diameter ; and the common mushroom varies * Fungus. t The tree fungus. VEGETABLE PHYSIOLOGY. 7 in size, from that of a pea, to a circumference of three feet. All cellular matter is, by a fundamental law of nature, arranged into the specific forms of the organi- sation and specific structure of every different kind of plant ; distinguishing them from each other in form, colour, and all other physical properties. II. ORGANISATION* THE economy of vegetation requires a certain apparatus or system of organs. These are principally the vital, nutritive, conducting, preservative, and reproductive. The vital organs are those parts of plants in which the life resides, and whence all the growth and expan- sion of the different members originate. In a seed, it is the embryo of the future plant; and this, after it is developed, continues possessed of vitality variously located in the fabric, according to the nature or pecu- liar conformation of the plant itself. In some it has a fixed station ; whence all divisions proceed. It is so located in bulbous and tuberous stems, and in what is called the crown of many herbaceous plants. In the case of shrubs, trees, and many suifruticose and herbaceous plants, the vital principle is not confined to one place, but is borne up with and spread over the exterior of the stem and branches, sometimes into the leaves, and over the surface of the wood in the roots also. When existing as in a seed it is called the corculum ; and the same term may not be mis- applied in speaking of it as found in bulbs and tubers; but in respect of trees, shrubs, &c., a better designa- tion will be the vital indusium or envelope, because VEGETABLE PHYSIOLOGY. 9 it covers the whole surface of the wood of these plants*. In all cases the vital principle has the property of resisting extinction for a greater or lesser length of time : of increasing- by expansion or subdivision without destruction, and by oviparous and viviparous reproduction. Nutritive Organs. To enable the vegetable being to subsist and perform its various functions, it is provided with organs which are recipients of aqueous or gaseous nutrition attracted from the earth and air. The fibres or spongioles of the subterranean stems, the glands and pores of the cuticle, are the chief inlets of vegetable food ; and by which they receive what is proper, but by which they cannot always reject what is noxious. The root fibres are only the recipients of the crude pabulum; this, after being- introduced to the system, becomes assimilated with the inherent qualities of the plant. In vain we search the soil for qualities similar to those found in the roots, stem, leaves, and fruit ; and therefore conclude that in the chambers or vessels * It may appear somewhat problematical, or at least an unneces- sary distinction, to assert that any one member of a healthily grow- ing plant possesses more vitality than another; but such distinction is absolutely necessary in the present inquiry, as will appear in the sequel. Here also an apology may be due for the use of new terms : but as they are meant to designate a member which has been hitherto unnoticed, or confounded with others, the introduction of them on this account may be excusable. 10 VEGETABLE PHYSIOLOGY. of the plant are elaborated its essential qualities. The radicle fibre is a very delicate organ ; it appears to be elongated by protrusion of its centre. The apex is rather blunt, but a notable portion of its length is thickly beset with hair-like appendages which are probably absorbents. Fibres diverge from where they are exserted in quest of humidity, naturally receding from dry air, and turn from it whether it be above or beneath them. They are not averse to light provided it descends upon them through the medium of water or very moist air. That such fibres are only ejected in humid air, is evident from the circumstance of their never appearing on roots produced in the air, as those of Epidendrum, Pandanus, and many other plants ; from which it may be inferred, that when such organs are destitute of fibres they are furnished with ab- sorbent valves, or stomata, to admit nutritious fluids from the atmosphere. The growth of fibres is simultaneous with that of the other parts of the system ; each additional shoot above requires in its development the assistance of new fibres below. But their powers and properties will be more fully adverted to when we come to describe the under-ground stems of plants. Conducting Organs. All vegetable structure is permeable to currents of fluids. In the lowest grade of cellular es, water seems to be transfusible in any direction throughout the whole mass of the plant, as we see it is in a bit of common sponge. In the higher orders of vasculares, the cellular frame is VEGETABLE PHYSIOLOGY. 11 diversified by numerous tubes or intercellular openings which act as conductors of the fluids whether essen- tial or imbibed. These vessels having- generally a longitudinal position, as if only intended for convey- ing the sap directly upwards or downwards, and though there are no very visible horizontally lying tubes, it is notwithstanding quite evident there is a lateral transfusion of the sap, probably by the diver- gent or convergent partitions, and by intercellular communication. These tubes are not always surcharged with sap, some of them on this account have been called air vessels. No doubt air itself, as well as fluids of a less gross character, are necessary in the interior, as well as to the exterior of plants. Electricity is deemed one of the most effective agents in the pheno- mena of vegetation ; and the spiral vessels found on young shoots have been considered as the special ducts for the conduction of electric currents. These are circumstances, however, which are received and credited more on the ground of their plausibility, than resting on any practical proofs which have been had of their reality. The bark, from its suberous character and station, is well calculated for the conduction of fluids this, the alburnum, and particularly in the space between them in the spring, we see, are the principal channels for the flow of the sap. The action of these tubular organs is greatly assisted by the proper leaves and other leafy expansions attached to the bark; even the armature, it is probable, does a like office. 12 VEGETABLE PHYSIOLOGY. Preservative Organs. The shells of seeds, the protuberant envelope of bulbs, the pulpy mass of tubers, the bark of trees and shrubs, and the gene- ral cuticle of plants, are the preservative appendages. The coverings of seeds are various in number, tex- ture, and durability. Some of them yield quickly to the decomposing action of the air; whilst others, defended by the horny texture the oleaginous or resinous quality of the shell are wonderfully per- sistent, whether exposed on the surface of, or buried deep in, the ground. Bark is the common covering of trees, &c. It is composed of distinct layers of cellular matter annually detached from the vital membrane, and consequently increasing in thickness every year during the life of the tree. In some cases, however, the outer layer is thrown off when two or three years old, but in gene- ral it is persistent. The exterior layers being first deposited, they of course must gradually give way to the subsequent internal accretion of the stem, and consequently are parted into longitudinal rifts to give room to the new layers of wood and liber. There are some smooth barked trees whose annual layers of liber are remarkably thin and distensible ; the first layers of which, instead of being fractured perpen- dicularly, are stretched horizontally, embracing the axis like a series of hoops. The ligneous axis of a tree may be deemed a pre- servative member, because, though when left by the vitality, and no longer a channel for the sap, it sooner or later decays, yet before this takes places, it answers VEGETABLE PHYSIOLOGY. 13 the purpose of a prop to the branched head, and of course preserves the living- parts from being- laid prostrate by the winds. Reproductive Organs. Plants reproduce them- selves by seeds, and by what are called offsets or suckers. The flowers precede and produce the for- mer, and the vital membrane the latter. Herbs, and many trees and shrubs, extend themselves by stolones; some by the rooting* of their branches which happen to touch the ground; and others there are which eject roots from their lofty branches, enter the soil, and thence throw up a new birth of stems. The foregoing is a brief sketch of the organisation; but as all the principal organs will hereafter be described, and figured if necessary, in the order of their development, nothing farther need be added in this place. 14 III VEGETABLE LIFE. HAVING endeavoured to convey ideas of the ele- ments and organisation of vegetables, we come now to describe that phenomenon called the life, or what may be rationally deemed the causes of the motion and enlargement of these curious organised bodies. When we reflect that vegetable matter is com- posed of a mass or compages of areolae, whose mem- branous pellicles are extremely thin, and capable of being distended from an inconceivably small to a larger volume ; and if we consider that those small cells are more or less filled with either a gaseous or aqueous constituent; and farther admit that such constituents are excitable into increased bulk by extraneous agents, we may readily conceive that enlargement of the whole mass must necessarily fol- low such excitement. The primitive vesicles or cells are not visible to the keenest eye, nor, indeed, to the most powerful microscope ; and when enlarged to their utmost dimensions they are, in the generality of plants, very diminutive. Even the tubes formed within the cel- lular body are only detectible by optical assistance. This assistance is sufficient to convince us, however, that the cells swell from a smaller to a larger size ; VEGETABLE LIFE. 15 and if each be capable of amplification, no surprise need be felt, considering- their immense numbers, at the vast productions which rise from the propago of a Lycoperdon*, or from a seed or sucker of an Agave Americana, f In stems and petioles of the leaves of the larger kinds of herbs, as Musa, Crinum, and the like, the cells are ample, and therefore easily distinguishable by the naked eye ; and the elongated cells between the joints of hollow stems, are striking instances of the expansive power of their contents, and the dis- tensible nature of their cellular sheaths. Thus the inflation (if we may use the term) of the cells gives magnitude, and their disposition or arrangement with respect to each other, constitutes the essential character of the plant. There are many instances of ebuDition or effer- vescence observable in the chemical action of different bodies when mixed together, either by heat generated or applied ; but such are only the effects of the t-ommon laws of attraction, repulsion &c., and are never attributed to anything like vitality ; and, had vegetable growth no other properties than that of amplification, a very close resemblance might be drawn between it and the transformations, often visible in unorganised and inanimate matter. But vegetable life has other most important and distinct properties. It is continuous, without having, in many cases, any assignable limit. Like that of * Puff ball, t American Aloe, 16 VEGETABLE LIFE. animals, it is active or dormant ; in the one case constantly progressing- as from the centre of a circle, diverging every way around: or, if inert, reposing safely in a kind of slumber, and imparting a con- servative principle to the parts immediately sur- rounding it. In seed it remains dormant, but without extinction, for ages. This is attributable to the preservative character of the coverings its intrinsic qualities and to the absence of those atmospheric influences, which, when present, effect the development of the plant. Whole plants, or parts of plants, if defended from the influence of air or extreme changes of weather, may lie inert and uninjured for many months, or years; and, when replaced in a natural situation, recommence growth and exhibit every vegetable function. From these instances it is quite obvious that vege- table life is a real, though only a passive principle. Real in its power of preservation even whilst asleep ; and passive by virtue of its excitability, and the ex- pansive nature of the frame in which it is contained. Vegetable life commences and is progressive under every degree of heat between the freezing point, and 150 of Fahrenheit. It is arrested when the tempera- ture is at or below 32. All vegetation suifers during frost, and many plants are utterly destroyed by it. This happens in consequence of the juices becom- ing crystallised, by which the cells are disrupted, and the healthy organisation destroyed. Plants having an VEGETABLE LIFE. 17 aqueous sap are more liable to be killed by frost than those charged with a gummy or resinous juice. So those which are growing freely suffer more than such as are dormant. Some plants, as young wheat for instance, are only withered by frost, without laceration of their cellular structure ; as on the return of warmth they regain their rigidity. Extreme drought is fatal to the vitality of all plants ; exhaustion of the juices by evaporation, causes an injurious shrinking of the vascular apparatus, and consequent morbosity of the organisation. Some plants are naturally defended against drought by the thick pulpy substance of their stems and leaves, such are what are called succulents : others are protected from the heat of summer by protuberant appendages of their stems ; these are bulbs and tubers : and there are certain plants, which, if accidentally placed on a soil too dry for their constitution, form for themselves cellular protuberances at the base of their stems, to serve as provisional reservoirs of moisture ; such is the Phleum prafense. Although heat and moisture be absolutely neces- sary to vegetable development, they are of them- selves inadequate to cause even the germination of seeds ; because such as lie deeply buried in the earth receive no stimulus from the heat and moisture with which they are there surrounded : air and its quali- ties are wanting; and without which no develop- ment can take place. If seed be exposed to perfectly dry air, it receives no excitement therefrom ; so that c 18 VEGETABLE LIFE. it is only the union of heat, air, and water in due proportions, tog-ether with the influence of light, which can prompt vegetable life into perfect action. The regermination of trees, and all the vernal movements of plants, are usually and properly as- cribed to the improved temperature of the season. Yet we cannot suppose that higher temperature is the sole cause ; for this reason many plants, instead of being carried along by the increasing heat of the summer, actually become torpid at the end of spring. Such are almost all our bulbs and tubers cultivated in the flower garden: and such are the first to com- mence a new growth in autumn, and even put forth their flowers in winter. As the precocious move- ments exhibited by many bulbs, tubers, and some of the amentaceous plants, cannot be attributed to increased temperature, what reason can we assign for this their seemingly premature evolution ? It may be answered, that every plant is so constituted as best suits the purposes of reproduction. Bulbous, or other protuberances of the stem, are no other than safeguards to the vitality of the plant during the heat of summer ; for during that time it is dor- mant, and continues so till the setting in of the autumnal rains, when the temperature is every day declining ; so that the decreasing heat, which arrests the growth of almost all other plants, affects not bulbs. This is owing, no doubt, to the constitutional formation of the bulb, its seat of life is centrally posited, and defended by a thick investment of VEGETABLE LIFE. 19 old or new incrassated leaves, acting- like those foliar members of buds called hybernacula. Hence the centre is sufficiently protected from the cold air, and the roots drawing 1 nourishment from a considerable depth in the ground, progress whilst other plants, not similarly situated, are at rest. Besides, these summer sleeping plants may acquire some chemical maturation during their rest, which prepares them for instant action on the return of the temperate season. Very differently constituted are trees and shrubs. Their vitality is not local but spread over their whole exterior, and consequently exposed to the depressing- effects of cold air and frost ; so also herbaceous per- ennials having a system of attenuated fibrous roots, and generally near the surface, are kept in cheek by the chilled air. Respecting amentaceous plants, as Corylus for instance, there is no ostensible circumstance which can be said to cause the early protrusion of their male and female flowers, more than affects other plants of similar conformation and hardihood. It is true the catkins are mostly formed in the previous summer, and their winter growth is only a relaxive elongation without rigidity of sap vessels or fibres, to endanger the organisation by frost ; indeed flowering, at this dark season, is one of those wise provisions of nature which excites our admiration, for assuredly were such delicate and attenuated bodies exposed to the withering winds and sunshine of the month of March, they would be quickly destroyed before the pollen c2 20 VEGETABLE LIFE. could be ripened and dispersed. We have also in- stances of many Icosandrious plants whose stamina are extremely delicate, and which flower early in spring. May this not be attributed to a law of nature, which, by bringing- out the flowers early, secures them from the effects of ardent sunshine ? The night- flowering Cereus is a remarkable instance of flowers of attenuated structure shunning the scorching effect? of the sun. Vegetable life exists in a twofold state, viz. that in which it is dormant, as has already been alluded to, and that in which it is actively swelling the cellular apparatus containing it into greater volume. The wood and inner layers of bark are said to be alive so long as they share any of the rising sap, or act organ- ically in its conduction, notwithstanding the actual vitality has long left them. The living principle is always found between the wood and liber. It is, we are led to imagine, a distinct member of the plant ; and as such will be described, when the other members of the system come under review. Suffice it to add here, that this member is the foun- tain of life and organisation ; and so long as it re- mains possessed of its essential sap, it is capable of expansion and reproduction of every constitutional member of the plant. Besides the swelling motion of vegetables there are other motions, which may be called accidental and extraordinary. Accidental motions are those occa- sioned by the state of the soil or weather. When VEGETABLE LIFE. '21 either is too dry, the leaves and shoots become flaccid and droop from their natural position ; but when humid air or water is restored to the plant, the flaccid parts recover their rigidity and position : such movements are easily accounted for. Other motions are produced by the action of heat and light, which have the effect of expanding flowers and foliage ; but, being withdrawn, they relapse to a state of repose, which is called their sleep. The pedicels of some flowers, as Convolvulus, are erect or horizontal while in bloom, but immediately turn downward to ripen the seed. Extraordinary motions are those of the pinnulse of Desmodium gyrans * ; the collapsing of the leaflets of Dioncea^, and Mimosa I, the elastic action of the stamens of Berberis^ and that of the petals of some of the Orchidece || . All these spon- taneous motions are wonderful ; and cannot be ratio- nally accounted for from any knowledge we possess of the articulations which become so suddenly and alternately lax and rigid. These instances sufficiently prove that plants are sensitive and irritable ; whence some philosophers have come to the conclusion, that they are actually endowed with muscles, a system of nerves, and not only recede from the contact of animals, but, more- over, are conscious of pleasure and pain ! It is certain that the appearance of a healthy plant soon after the morning sun shines upon it, and while " spreading its enamoured bosom to his ray," in some measure jus- * Moving plant. -j- Ply -trap. * Sensitive plant. Berberry. Jj Orchis. 22 VEGETABLE LIFE. tities this idea; and it cannot be denied, that the effects of genial warmth and light are as fully felt and enjoyed by vegetables as by animals. The constitutional sensitiveness of plants is also evinced by the branches of a tree planted near a wall turning away from, before reaching, it ; and also all growth tending to the strongest light is in both cases attributed to the attraction of, or the tendency of vegetation to, that body, whether solar or ignes- cent*. The tendency of radical fibres extending themselves towards heat, moisture, or rich food, is also curious ; and can only be explained by ascribing it to the law of attraction, because all bodies, which mutually attract each other, form between themselves a current of their fluids ; and thus, while streaming towards the recipient, induce the protrusion of the spongioles of the latter to meet it hence their elongation. From all these circumstances, we may rationally conclude that, notwithstanding much of the pheno- mena of vegetation may be traced to combined che- mical and physical action, we must admit the exist- ence of a vital principle, which seems independent thereof ; more especially in its power of existing for ages unimpaired in the bowels of the earth ; and, while thus dormant, may be best defined by the remark, that vegetable life is an excitable or fermentative fluid, contained in an organised expansible body. * The flower of the Crocus may he opened by candle-light ; and also by fire-heat, though partially shaded. 23 DISTINCTIONS OF VEGETABLES. THE vegetable kingdom is naturally divided, ac- cording to some old botanists, into four divisions, namely, trees, shrubs, herbs, and what may be called terrene plants. Recently published lists enumerate above one hundred thousand in the whole : compris- ing 3416 genera ; above 32,000 species ; with varie- ties and sub-varieties innumerable ! For the facility of studying, identifying, and describing this vast assemblage of vegetable produc- tions, botanists have arranged it into Divisions, founded on the elemental structure, viz. vasculares and cellulares. Classes, on the number of the cotyledons or semi- nal leaves, as respects monocotyledones and dicoty- ledones, and on the want of, or presence of, foliaceous structure in the plants of acotyledones. Sub-divisions, on the calyx and corolla being, or not being distinct. Sub-classes, on the situation of the stamens. Orders, on the most prevailing character. Tribes, on near alliances. Genera, on ancient and modern names and cha- racters. Species, on individual character. 24 DISTINCTIONS OF VEGETABLES. The further illustration of this, or any other sys- tematic arrangement of plants, is not intended in these essays, here it would be superfluous, seeing there are already so many excellent hooks on the subject. But by taking a general view of the vege- table kingdom, opportunity will be afforded to mark the physical structure, notice the organic functions, and describe the manner of development of the va- rious plants which differ most from each other in constitutional character and appearance. The elementary structure and organisation have been already adverted to, and which sufficiently mark the distinguishing characteristics of Jussieas two grand divisions : we may next notice the peculiarities of development which identify the classes of his natural arrangement : viz. Acotyledones. Are plants which rise destitute of visible seed-leaves. Linnaeus long ago noticed the evident difference there is between the first foliar expansions (when there are any such) of his Cryp- togamia and those of the more perfect plants ; con- ceiving the seedlings of the former to be more like viviparous than oviparous progeny : hence he called them propagines. The seed-leaves of the crypto- gamous Foliacece being similar in structure and ap- pearance to all that follow, and the whole plant being mostly of a cellular and uniform texture, the dis- tinction is obvious. We say mostly, because Jussieu himself admits, that some of the Filices are partly vascular, though without spiral vessels. DISTINCTIONS OF VEGETABLES. 25 It may be observed of this class, that in all proba- bility future botanists may find it necessary to remove some of the genera now included in it : already it has been discovered that the first expanded member of a fern is different from the succeeding- leaves ; conse- quently, if this be not a mistake, they should be removed to the second class : and as a great majority of acotyledonece have very small seeds, if seeds they may be called, their evolved parts are extremely minute, a circumstance which renders their classifi- cation a task of some difficulty. Monocotyledones. Are such plants as rise with only one seed-leaf. There is some obscurity about this characteristic distinction. The first foliole or member, called the cotyledon, is so much like the perfect leaves in shape and texture, though not in size, that there is room for doubt. If we take Pan- cratium and Cocos as examples, it appears that the first leaves of these plants are in fact real leaves, and not cotyledons. The infant plant is nourished for some considerable time by the albumen or kernel of the seed, and, therefore, unexpanded cotyledons would have been perhaps the most accurate distinction. Dicotyledones. Are plants furnished with two or more seminal leaves, and which are expanded in the air, as Brdssica*, or under the surface of the ground, as Faba\. The annexed figures represent the germination of the classes. * Cabbage. -f Garden bean. 26 DISTINCTIONS OF VEGETABLES. Fig. 6. Fig. 7. Fig. 8 Aeotyledoneae. Monocotyledoneae. Dicotyledonear. Conferva. Cocos. Sinapis. These are the divisions and classes under which the vegetable kingdom is arranged by the celebrated Jussieu, and as improved by the no less celebrated De Candolle. Its excellence as a system consists in its being founded on the most remarkable and obvious distinctions observable in nature, namely in ele- mental structure, in the components of the seed, in the arrangement of the floral appendages, on affinity in resemblance and essential qualities, and on general character. It is very probable that its author conceived, at the outset, his scheme would not only simplify, but greatly compress the science into narrower bounds, and thereby enable the student to grasp the whole with but little application. But this, if ever expected, has riot been verified ; for such is the diversity of vegetable forms and qualities, that the system has become in his own and followers' hands, so very complex and diffuse, that the orders, ACOTYLEDONE^E. 27 sub-orders, sections, and alliances, are so multiplied and multiplying to such an interminable extent, that it is in some degree discouraging to the student, as well as to some practical botanists. Still the out- lines and striking characteristics of the divisions, classes, and major part of the orders are so truly natural and satisfactory, that it is certainly a pleasant and interesting treat to be led through the labyrinths of vegetation by such a master ; though it may be safely predicted, that it is reserved for some future disciple to re-arrange the Jussieuan system : who by disregarding minor distinctions, doubtful alliances, and mere shades of physical difference, may render the whole both more simple and concise. SECTION I. ACOTYLEDONEJE. IN the following review we may repeat that it is only the more ostensible features of the system which are intended to be noticed; short descriptions, and figures when necessary, will accomplish what is pro- posed, viz. to give a plain survey of the physical constitution of plants. In order to this it will be expedient to begin with the lowest grade, viz. Fungi. The microscope has very much extended our knowledge of many minute plants which would for ever have escaped the naked eye ; and it may be presumed, that numbers still remain unknown, not only on the surface of the earth and on various mine- 28 ACOTYLEDONE^E. ral, vegetable, and animal substances, but actually within them. However close the texture of rocks and stones, vegetation attaches itself to them. The discolorations or weather stains on these and on buildings are caused by the presence of Lichens, Conferva, &c. ; and wood of all kinds is the habitat of numerous Fungi. These last not only exist on the exterior, but penetrate and even decompose the hardest timber. The dry-rot appears to be no other than the seizure and destruction of a fungus* ; and from * Whether the dry-rot, Merulius destruens he the cause, or only the effect of decay in timher is a point not yet sufficiently ascer- tained hy naturalists. As many of the congeners of this plant affect rotten vegetahle suhstances, it is quite natural to suppose that decay precedes the attack of the fungus, and therefore the conclusion is, that timber so destroyed, must have heen either imperfectly sea- soned, or laid in a place deficient of due ventilation. It is well known that the hasement timbers of buildings are more liable to dry-rot, than those on the upper stories, and that if oil-cloth or other covering impenetrable to air and moisture lie long unmoved in the same place, dry-rot will appear sooner or later in the boards beneath ; showing decidedly, that in such cases, want of free air invites merulius. But to what can we impute the decomposition of the massive ribs of a ship of war, while yet on the stocks, and before being either planked or sheathed, and exposed to full and dry air for two or three years ? Here there is neither oil cloth or paint to shut in sap that might be detrimental ; on the contrary, every pre- caution is taken that the scantling be perfectly seasoned. Still before the ship is launched, these timbers, though apparently sound and perfect to the eye, are found defective the interior being only a mass of dust. If we examine its progress we shall see that the sound wood is divided from the unsound by a very slender line ; and that the fibrous tissue of the plant appears to absorb the juice and decompose the cellular structure of the wood. ACOTYLEDONE^. 29 the progress of this plant, as well as that of common cultivated mushroom, there is reason to suspect that like all other plants developed in the air, they are composed of various members, viz. roots, branches, and fructification, the latter only appearing 1 on the surface. It is perfectly true that, on examination of the mushroom plant, there appears only a system of root-like fibres and the fructification ; but as these fibres spread themselves to a considerable distance round their first station, and bear the edible part on their extremities, we must either consider them real branches, or, if roots, that they are capable of bearing fruit*, a circumstance which has no parallel in the vegetable kingdom. Inferior tribes of plants which inhabit the depths of the ocean, lakes, and rivers, are composed of various organs, as roots, stems, &c., and why may not such as the Fungi be similarly organised ? Among the latter, however, there is at least one exception, namely, Tuber (the Truffle) which is decidedly subterranean and apparently de- stitute of any other parts than an irregularly globose tuber, without visible stem or branches : whence a few slender fibres only are exserted. How the tuber is reproduced remains a mystery ; whether by incon- spicuous sexual organs or by viviparous subdivision is not ascertained, any further than that very small tubers are found near the larger. * It may sound uncouthly to call a mushroom a fruit, but it is as proper to call it so as it is to call the pulp of an apple the fruit. 30 ACOTYLEDONE^E. The whole division Acotyledonece is no less remark- able in habitat than obscure in the manner of repro- duction. The plants included in it are in duration, ephemeral, annual, or perennial ; in form filaceous or foliaceous ; in consistence, carnose, coriaceous, mem- branaceous, crustaceous, fibrous, or gelatinous ; in station they are found rooted in earth, adhering to rocks and stones, or as parasites on other plants ; existing chiefly in cold humid regions either in the open air, floating on, or constantly submerged in water ; from the motion of which they are, like aquatic animals, defended by a mucus, acting instead of a cuticle, covering their whole exterior. But of whatever form or magnitude they may be, their elementary structure, with but few exceptions, is cel- lular. The most simple of this division is, perhaps, the Tremella ; it being only a formless body of jelly, bearing, even in its most mature state, very slight marks of organisation. The most complicated and perfect plants are contained in the class Foliacece, viz. the Equisitacece^ and the Filices: some of the latter arrive at a considerable and tree-like size, and are most elegant in their forms, and curious in their evolution. Many of the ferns have tuberous stems which are perennial, and reptant either beneath or on the sur- face of the ground. The fine powder discharged from the fronds, if not seed, is certainly a vital essence ; as plants are easily raised by sowing it on a proper soil and in a favourable situation. And of its tena- ACOTYLEDONE^E. 31 city of life, it may be observed as proof, that plants have been raised from the dust of specimens after being kept in a hortus siccus for a period of forty years. The fine dust discharged by the Fungi is also, no doubt, the seminal produce ; because, how else can it be so generally distributed as we find it to be in the case of the common mushroom ? In the cultivation of this fungus we generally keep fragments of the plant itself under the name of spawn; but it is well known that the mushroom may be generated by merely collecting substances which are known to be affected by the plant. These put together in a dry place, and applying to the mass a moderate degree of artificial heat, the seeds of the mushroom accidentally therein are developed, and the perfect plant with its edible part obtained. This fact is so constantly before our eyes that specific modes of cultivation are founded on it, and, being attended with success, leave no doubt of the idea, that the light and almost impalpable dust of the mushroom is, in fact, real seed ; which is wafted around by the winds, and wherever deposited under favourable circumstances, germinates and comes to perfection. There are many microscopic species of Fungi which are only discoverable by their effects. One of the most destructive is the rust or blight in wheat and other cereals. 32 ACOTYLEDONEJE. Fig. .9. Pucinia graminis on the straw of wheat. Its prevalence in some seasons, can only be ac- counted for by supposing-, that the seeds are conveyed from the perfect plants by the wind, and, lodging- in the pores or cells or cuticle of the straw, veg-etate and come to maturity. It is remarked of the Fungi, as well as of many of the other orders, that they affect peculiar substances as their habitat. Some are only met with on particular kinds of dead or dying- trees ; many luxuriate on the bark, others on decayed roots, and several occupy the solid timber in the various stages of its decomposition. Many attach themselves to particular kinds of rock or earth, whilst others prefer the leaves of living plants. The growth of this division takes place by the inflation of the cellular structure ; commencing, as before observed, at a little distance from the centre, and proceeding outwards, Fig. 5. Whether the sub- stance be carnose, membranaceous, or foliaceous, the exterior is invariably covered with a dense film or cuticle, which in many cases parts readily from the MONOCOTYLEDONE^E. interior mass. Hardly any of these plants appear to have any definite magnitude ; individuals of the same species being very different in size : the common mushroom, we see, varies from one inch to one foot in diameter. Many of the acotyledones are evanescent and quickly perishable in the open air ; yet, when dried and kept free from moisture, the lichens and fungi change to a leathery consistence, and then are very durable. Individuals of almost all the orders are used as articles of diet in the arts or materia medica. Some of this class are remarkable for their tenacity of life. Several of the mosses after being kept in cabinets, as specimens or otherwise, for many years, and in which time they have become completely dried, nevertheless, as soon as they are exposed to moist air, recover vitality, and grow again as well as ever. SECTION II. MONOCOTYLEDONE^E. LEAVING the acotyledonese, we now enter on the most simple order of the monocotyledonese, namely, the Graminece*. In all moist and temperate climates these form the general covering of the earth. They furnish man with the " staff of life," and for the herds and flocks of our depasturing animals are the most useful of all others. * Grasses. D 34 MONOCOTYLEDONS^. The structure of the grasses is extremely simple ; consisting of fibrous roots issuing from a flattened crown or collet, whence spring hollow or solid jointed stems linear leaves borne on the joints of the stem, which latter bear a terminal spike or panicle of per- fect or phsenogamous flowers and seed. In duration they are either annual, as Hordeum vulgar e ; biennial, as Bromus tectorum; or perennial, as Dactylus glomevata. Some are minute herbs, forming a thick turf ; others are arborescent, rising to the height of many feet ; mostly stoloniferous, by which they are increased as well as by seed. The physical structure, vital powers, and manner of development, may be described as follows, viz : The seed is covered by a husk of cellular tissue, inclosing a farinaceous albumen which contains the corculum or embryo plant. The embryo, as in all other cases, is composed of two principles, viz. the rostellum from which the radicle fibres are exserted, and the plumula, which rises in the air. Both proceed from the base of the seed ; the first leaf hourly in- creasing in height, and succeeded by others evolved from within it ; in fact the first leaf evolves all the others, together with the stem and fructification. Botanists are not agreed which member of the infant plant is the true cotyledon. At the base of each stem there is a small scale-like substance called the vitellus, and immediately above this there is a delicate sheath embracing the incipient leaves and stem, and through which they come forth. The latter MONOCOTYLEDONS^. 35 is considered the true cotyledon by some authors ; while others deem the former the true one, in order to be consistent with the characteristic title of the class. Be this as it may, it is certain neither do the imputed office of cotyledons ; that being" performed by the albumen, which yields the nourishment necessary for the young plant till the radicles have established themselves in the soil. The corculum, that is, the body whence the roots and stem originate, is a compound organ, consisting of the rudiments of many sets of roots, and of many culms. Each joint of the culms is constituted like the corculum, i. e., it is capable of producing both roots and new sets of shoots, if placed in favouring circumstances. Whether a single grain (of wheat for instance) throws up one or ten culms, depends entirely on the fertility of the soil, favourable season, or space allowed it to grow in ; consequently, the wheat plant is capable of repeated division and sub- division by art to any extent during the spring months ; showing that the corculum is an aggre- gation of vital essences which are developed either singly or collectively. The following figures are illustrative of the fore- going description, and may be considered as types of the germination and constitution of the Graminece in general, whether annual or perennial. D 2 36 Fig. 10. MONOCOTYLEDONEJE. Fig. 11. Fig. 12. Germination of Barley. Germination of Wheat. Development of perennial Gramineae. The culms are incipiently depressed cones ; in this state they exist, no doubt, even in the seed. Those of wheat generally consist of eight joints ; the first and second at the bottom, if the grain has been deposited at the proper depth, are short, every higher one increasing in length the last bearing the ear being the longest. The culms progress in height by the inflation and perpendicular extension of the large cells occupying the centre between the joints, and of the denser cellular tissue composing the ex- terior cylinder. The latter is also inflated horizon- tally ; its inner side becoming vascular, and forming the principal channel for the ascent of the sap. The exterior surface of the stem is somewhat fluted, dense, MONOCOTYLEDONEJE. 37 and pierced at pretty regular distances by some of the horizontally lying cells, Fig. 9, forming stomata or openings for the emission or admission of aerial fluids. The exterior is also in some cases remarkably smooth and glossy, and ultimately becomes membra- nous, i. e. dense cellular matter and of considerable tenacity. It is from the compound character of the corculum or crown of these plants, that, under favourable cir- cumstances of soil and season, the annual species are so productive of thick and heavy crops. On very inferior land a seed may only bring a single culm and ear to perfection, whilst on rich land from seven to twenty is the usual produce. From the same circumstance it is, that the perennial species spread themselves on the surface and form so thick a turf. In both cases this property may be excited by the operation of the sithe or close-grazing animals preventing the seeding of the plants. Such mutila- tion, frequently repeated, even changes the nature of some species so much, that annuals become biennials, and biennials almost perennial in duration ; and this merely from denying them the principal aim of their being, the production of seed. There is another kind of mutilation which in- creases the volume and produce of grasses ; it has been already observed, that each culm has its own system of roots, but which remain inert if the culm itself be not called into action ; when, however, the primary productions are cut, eaten over, or trampled 38 MONOCOTYLEDONE^. down, the secondary offsets immediately come forth in greater numbers and strength than if the first developed parts of the plant had sustained no injury. Hence the propriety of eating down rank crops of -wheat, mowing thin crops of grass, and drag-har- rowing old meadows-. Next in value to those Graminece which yield the most nutritious food and drink to man, and pasturage to our herds, ranks the Saccharum qfficinale, or sugar-cane, so universally employed as an article in diet, and many other purposes of human life. It is a perennial, having the same structure and vital powers as the other grasses, only of a more robust habit and greater magnitude. But the most majestic in size is the Bambusa arundinacea. This plant throws up a thicket of arborescent culms, which rise to the height of forty feet, or even more, annually increasing in number, and extending from the first station. The culms, though so herbaceous when they first issue from the ground as to be cut like asparagus and used green as a pickle, become at last perfectly ligneous, and so exceedingly compact, elas- tic, and durable, that, for the construction of Indian cabins, implements, and household furniture, the bamboo excels all other kinds of wood. Car ices et Juncece. Next to the grasses are ranked these generally worthless tribes. Their phy- sical structure is rather more complex than the pre- ceding, having a few more members in the flowers. They are mostly inhabitants of barren ground, the MONOCOTYLEDONEJE. 39 sea-shore, borders of lakes and streams, and in pools of stagnant water. Some few have showy flowers ; but in general they are rigid herbs, fit only for the purpose of the door-mat and chair maker. The larger rushes, it is well known, have a large vascular pith, which, when divested of the cuticle, is used as wicks for candles. Arums, and their alliances, are the next grade of herbaceous plants. They have mostly tuberous sub- terranean stems, or thick fleshy roots, many of which are edible. The A. Indicum (?) is extensively cul- tivated in China for its tubers, which, with those of the water lily, form the bulk of such kind of culi- nary vegetables in the markets at Canton. The leaves of the Caladium esculentum are used as spinach in India; but in general the leaves of this tribe of plants contain a bitter principle, which renders them unsavoury and sometimes dangerous. Passing these comparatively humble herbs, together with the rest of the Aroidece, we next come to the conspicuous. Pandanece and Palmes. These two orders, though nearly allied to each other, are very different in their constitutional conformation : the former being divisi- ble, naturally by off-sets, and artificially by cuttings, the latter not. The mode of rooting of some of the Pandanece is remarkable. The growth is continued in grades. Each successive expansion of leaves and stem is accompanied by an additional number of roots, which are produced not from the original 40 MONOCOTYLEDONEJE. collet, but from the articulations of the stem above. The first roots are only attached to, and specially connected with, the base of the stem ; the superior part of it is supported by monstrous fibres issuing- from the joints, which descend and fix themselves in the ground, acting like buttresses to the weighty head. During the descent of these large roots, it is quite evident that they are prolonged by the pro- trusion of their central parts ; and, what is very remarkable, thin films of cellular matter, similar to the sheaths on the young roots of Cruciferce, or like the liber of other plants, are frequently discharged from the point, like cups one within another, acting, before they fall off, like reservoirs of water for the sustentation of the tender point. This peculiarity was first brought to our notice by our intelligent friends, Messrs. Loddiges, of Hackney. The majestic tribe of palms occupies the middle station between herbs and what are properly called trees. Like the latter, they rise to a great height on a regular columnar stem, which, though herba- ceous at first, afterwards becomes ligneous ; but, like some other plants, they have at all times only a single tuft of leaves, without branches or other divi- sion of the axis. Some of the palms, it is said, present the extra- ordinary spectacle of being individual plants, pos- sessing but one vital essence, incapable of division, either by the roots, parts of the stem, or in any way save by seed ; which, when it has produced, the MONOCOTYLEDONEJE. 41 whole dies. Such are only temporary beings, and are those in which the fructification is terminal and solitary. No latent gems are seated in the roots or stem ; nor are there branches or buds. The growth is a continuous procession from the seed to the ripening of the fruit, the leaves being developed in succession. The bases of the petioles are articulated * with the axis, but are very persistingly united to each other, and aggregately form the exterior of the stem in the early stage of its growth. Hence it appears that the seedling palm is composed of roots which take a potent hold of the soil ; a thick invest- ment of many, probably a certain number of leaves, enclosing the fructification in their centre. As the growth advances the exterior leaves are first ex- panded, followed by the next within, and so pro- gressively till the last, evolving the spatha, is developed. During all this time the fructification is gradually rising and keeping pace with, but always some distance below, the tufts of fronds, till it nearly gains the summit, when, on the parting of the last leaves, the spatha, containing the fructification, comes forth, and bending with its own weight hangs gracefully below the foot-stalks of the leaves, where * From the appearance of the Phcenix, Cocus, and several other palms in India, it is not evident that the fronds articulate with the stem ; but it is affirmed by some botanists, that, after a long period of time, their bases at last fall off and leave the stem smooth and regularly scarred like the Bambusa. 42 MONOCOTYLEDONE.&. it flowers and ripens its fruit. If it be a sort whose flowers are terminal, the maturation of the fruit is the termination of the life of the plant. But the generality of palms exsert their flowers laterally from the axillae of the fronds, the latter being con- tinually produced from the centre of the stem, succeeding each other for a long series of years. Here it may be observed, that the palms, and all such constituted plants, gain altitude and diameter of stem by the progressive evolution of the leaves which rise from the interior : of course the body of the stem is enlarged by accretions or expansions within, not by concentric layers of ligneous matter on the exterior, as is the case with dicotyledonous shrubs and trees. The stem is, therefore, uniform in arrangement, composed of strong membranous fibres, embedded in suberous cellular matter, and without a distinct bark. Some of the palms have a notable pith, which may be separated from the fibres which surround and exist in it, and manufactured into a granular substance, commonly used as an article of diet by the natives of India. The common beverage of the inhabitants of Coro- mandel, called toddy, is drawn from the Cocos and some other palms, and obtained thus : as soon as the spadix turns downward its point is cut off, and from the wound flows the liquor, which is caught in pitchers slung to the stump. Thus collected, it is put toge- ther in a large vessel where it is allowed to ferment for a short time, when it is fit for use. This liquor is MONOCOTYLEDONEJE. 43 subacid, cooling 1 , and somewhat exhilarating, though not so as to inebriate. A strong spirit is also drawn from the toddy by distillation. The outer covering or husk of the cocoa nut, after being macerated in water, and beaten to discharge the cellular pulp, yields a coarse filaceous substance, of which mats, cordage, and even ships' cables are made ; and the kernel yields what are called milk, cream, and an abundance of useful oil. The wood of the Cocos and other palms, though of extremely coarse grain, is very durable, and much used in buildings and fences. The leaves or fronds, too, make excellent thatch. The date tree, Phoenix dactylifera, is a valuable fruit tree, as well for the use of the inhabitants where it grows, as an article of commerce. The Latania barbonica is said to be the most magnificent vege- table in nature. The next grades requiring notice are in structure more complex, though much more humble in stature, than the preceding. Among the Bromelidce and thickly beset, as are most of the other genera, with rigid spines. Ficoidece and Crassulacea are kindred orders' though perfectly distinct in a botanical point of view. The leaf-like appendages of the latter, and some of the former order, as well as Opuntidcece, cannot be considered simple leaves, because they contain all the principles of the entire plant. Any one of those members separated from the parent and placed in favourable circumstances, readily ejects roots and becomes a perfect plant. Bryophyllum produces vivi- parous progeny from the crenature of the leaves. In short, many of these succulent plants, composed of thick masses of vegetable matter interspersed with membranous fibres and sap vessels, can only be considered as consisting wholly of stem ; and this plenished in every part with the reproductive organs of vegetable life. Passiflorece and Curcubitacece are conspicuous orders ; the first for the grandeur of their flowers, the second for the usefulness of their fruit ; both furnishing fine objects of study to the physiologist, whether he regards the causes of the variety of form and colours of the one, or the manner of the enlarge- ment of the enormous fruit of some species of the other. Melons, cucumbers, gourds, &c., are well known exotic fruit -bearing herbs, formed for climbing, though generally trained on the surface of the ground. They are pruned and managed in the manner of fruit 82 DICOTYLEDONE^E. trees, a good deal of attention being required to check the natural luxuriance of their growth, and dispose them to yield their fruit in the shortest possible time. The fruit are produced on the side branches of the leading shoots ; these, therefore, are stopped in the early stages of their growth, to ensure the production of a tertiary order of branches, which are usually fertile. Next is the order Myrtdcece, containing many beautiful as well as useful plants. Among them a singular instance of inflorescence is exhibited by the Malaleuca, which ejects its flowers in long whorls from the buck of the young wood. In looking over the remainder of this sub-class we meet with many objects of floral beauty, and numerous genera possess- ing highly valuable medicinal and other useful quali- ties ; and in which, moroever, though variety of form, texture, and disposition of vegetable elements are really admirable, still there is no one genus so decidedly different from others as to require parti- cular notice. We may, however, notice the order Rosacece, and Leguminosce; the first contains many fine fruit trees, and among them should not be forgotten the estimable though humble strawberry. The constitutional structure of this favourite plant may be described as consisting of a compound crown, having one bud central and principal, surrounded by inferior gems of two descriptions, namely, branches and runners. The principal bud is developed and produces flowers and fruit in the second year ; DICOTYLEDONE^E. 83 during which runners are detached, and the branches are advanced by displaying- a new set of leaves, pre- paratory to yielding- flowers and fruit in the third year; in which season they also send forth runners, and numerous side branches, intended to extend the stool in all directions around. But it appears that, as the flowers are terminal, a bud cannot yield two crops ; and as every new set of succession branches becomes more and more diminished in strength, cultivators find that the original plants are not profitably kept after yielding- two crops, unless they are well dressed, and enjoy a favourable soil. So that it is only the produce of the principal bud, and that of the first set of branches in the third year of the plant's existence, that are considered as compensating for the trouble of cultivation. The runners sent off from the main body of the stool eject roots of their own, and soon become independent of the parent plant. The Leguminosce are a most conspicuous order. Their papilionaceous flowers and curiously shaped pods distinguish the greater number of them from all other plants. This order contains some of our most elegant trees and shrubs, and our wastes are enlivened by the golden-flowered broom, and ever- flowering furze. The most inconsiderable herbs, and the most stately trees, are also found in this order. In the sub-class Thalimiflorcs we see only, as in the preceding, variety of forms and qualities without any striking physical differences. We may, however, notice Impiitiens, merely for the purpose of alluding G 2 84 DICOTYLEDONE^E. to the dissilient property of its capsules, which, when ripe, burst with such force as to scatter the seeds to a considerable distance around. Tilia, or lime tree, is noted for its distinct and easily separable layers of bark, of which Russia mats are made. It has been said of this tree, that its liber is double, or that it produces two layers in each year ; but this requires confirmation. The filaceous coverings of the seeds found in the capsules of the Gosslpium^ are no less curious than useful ; and the fine tenacious fibres of the bark of Linum should not be overlooked. The form of the leaves of Saracenia is remarkable ; and the creeping rhyzomas of the Nelumbium deserve the attention of the cultivator. 85 ORGANIC STRUCTURE OF DICOTYLE- DONOUS PLANTS. HAVING in the foregoing" essays described the elements and the manner of the growth of vege- tables ; noticed their arrangement by Jussieu ; and taken a brief view of a few of the orders, from the most simple to the more complicated and perfect plants ; we have now to notice the constituents and organisation of the superior orders of Dicotyledonece, with a view to the illustration of those expedients of propagation and culture which are practicable only because they depend for success on the physical properties and powers of the plants themselves. The members of a dicotyledonous plant are the seed, root, collet, pith, perfect wood, imperfect wood, vital membrane, liber, bark, leaves, armature, flower, and those coverings of the seed called the fruit, with its appendages. In describing these different components it will not be possible to avoid reiteration ; many circum- stances before alluded to, or described, must be again mentioned ; but as the writer wishes above all things to make himself clearly understood, periphrasis, he hopes, may be excusable. Seeds. Are the oviparous progeny of plants. When naturally produced, that is when art has not inter- fered to change their constitutional properties, they contain the rudiments of a vegetable, capable of 86 ORGANIC STRUCTURE. being developed into the perfect form, and endowed with all the powers and qualities of that which pro- duced them. That the future plant exists in embryo in the seed can scarcely be doubted ; and though it is not easily conceivable that " the monarch of the wood " once reposed in an acorn I yet it must be admitted as a highly probable fact ; because, as has been before observed, vegetable growth is not an enlargement by addition of new, but only an ampli- fication of pre-existing parts. The inherent qualities are certainly augmented by the assimilation of the nutriment absorbed by the plant, by which also the cellular structure is enlarged and distended ; but this cannot add one additional cell to the structure. We are well aware of how some chemists account for the accretion of plants by saying, that as vege- tables are wholly composed of oxygen, hydrogen, and carbon, they are endowed with the power of extracting from the earth, air, and water, constant supplies of these chemical bodies to form all the newly developed parts which annually enlarge their volume. No one can rationally doubt the above position ; but the same philosophers go much farther, and maintain, that not only are vegetable elements so accumulated, but that the organisation itself is generated by combinations of them in a manner not easily conceivable by those not versed in chemical science. The fact is, vegetable growth, as observed above, is only an amplification of pre-existing organisation. That this idea is not merely hypothetical may be ORGANIC STRUCTURE. 87 averred, first, from the circumstance, that in the large bulb-like seeds of some of the Monocotyledonece, a considerable portion of the infant plant is distinctly visible on dissection, and the reason we see so little in these, and especially in small seed, is only owing to our limited powers of sight, and limited means of assisting those powers. Secondly, the seeds of Dioecious plants are male and female, and to the experienced eye are detectible before germination, especially in the genus Cannabis ; which is a proof that neither the sexes nor other specific form of the plant depend on any fortuitous combination of vegetable elements when not deranged by cultivation. Besides, the general resemblance of the parents and progeny from generation to generation among plants in a state of nature, is indubitable proof that the seeds inherit the rudiments of a perfect form, how- ever diminutive, from the first. The structure and components of seeds have already been noticed as consisting of various cover- ings, inclosing the cotyledons and infant plant. When germination takes place these coverings, intended for the preservation of the vitality during the inert state of the seed, are burst asunder, to allow the protrusion of the root, the cotyledons, and stem. The Root. Is first a blunt spur-like body, taper- ing as it descends into the earth, and exserting from its sides slender fibres, which are the receptive organs that collect the pabulum of the plant. These fibres are said to have a contractile power, by which they are withdrawn from dry air, and extended again into 88 ORGANIC STRUCTURE. that which is moist. As the roots progress in length they become divided and sub-divided into numerous ramifications. Such roots are properly called fibrous, not only because they are so at first, but because their extremities are always so ; and though those of trees become in time immensely incrassated towards the collet whence they originated they are still con- sidered and called fibrous. All plants are furnished with fibrous roots, but under different modifications of size and duration. Those of herbs are fugitive, in many cases annually dying off in the autumn, and renewed in the follow- ing spring ; of shrubs and trees the principals are permanent, with annual growths of young fibres. These principals appear to be only subterranean portions of the axis or stem ; because in most cases their components and structure are similar, except that they have no pith ; in this respect only they differ, both having concentric layers of perfect and imperfect wood, a vital envelope, liber, and numerous folds of bark; and in many instances both are furnished with incipient buds, which, when developed on the stem, are called shoots, but if from the root, are called suckers. The natural direction of all roots is from dry air and light, to moisture and darkness. The ascent of the plumula or infant stem may be in general satis- factorily accounted for ; but the contrary notion of the rostrum, or first root, is not so easily compre- hended. The latter is either repulsed by dry air and light, or attracted by moisture. Whether in the ORGANIC STRUCTURE. 89 earth or in pure water, roots invariably descend till they are out of the influence of dry air. This, from its withering effect, prevents all ejection of the deli- cate and sensitive spongioles ; and to escape from it, in ordinary circumstances, their course must be down- ward. To prove that there is no constitutional tendency in roots to obey the law of gravitation (as has been supposed) they will take an entirely oppo- site direction in quest of moisture, as may be seen within the overhanging- banks of roads or rivers when the bank has been undermined. Although fibrous roots are only ordinarily pro- duced below the collet, yet the power of exserting them is not wholly confined to that part of the system ; they are readily ejected from the stem, branches, and even the leaves also, under certain circumstances ; but this will be adverted to when we describe that member of the plant whence roots usually proceed. It is observed of radicles that they have the faculty of extending themselves towards humid heat, or to their food, whether that be simple water or nutritious gas. Is this a spontaneous and inherent power by which their organic action protrudes the fibres out- ward, or are these sensitive bodies attracted by the qualities to which they trend ? This phenemenon can only be attributed to the universal law of attrac- tion, as mentioned at page 22. The incidents which show this sensitive inclination of roots, are the following. If a tree be planted on the bank of a river, or on a spot of inferior soil near a bed of superior quality, a majority of the roots in 90 ORGANIC STRUCTURE. both cases will be prolonged towards the river and the richer soil. If a plant be so placed, that a greater degree of moist heat exist on one side than on the others, the roots will all trend towards the warmth. Again, if a solid body (which is retentive of heat, or, if cold, is attractive of moisture) be within reach of fibrous roots, they will extend towards and spread themselves on its surface, and seem to luxuriate in the cavity formed by the side of the solid and the soil. Roots both ascend and descend from their acci- dental stations in the soil to reach more suitable aliment. Those of the ash will cross from one side of a deep ditch to the other ; first descending when they reach the brink, passing under the bottom, and again ascending the opposite side till they arrive at the due point under the surface, whence they resume their horizontal course, keeping a uniform distance (about ten inches) from the air throughout their range. Mulching with rotten manure will bring roots to the surface ; and in dry seasons they will descend even into deleterious subsoils in quest of moisture. This last circumstance should be guarded against by the orchardist if possible ; for though it may be irrational to suppose that roots can be at- tracted by destructive qualities, yet the want of moisture may induce them beyond a proper depth. Although all plants are furnished with fibres, which issue from the extremities of the descending caudex, or immediately from the collet, there are, besides, other processes ejected by the latter organ which cannot with propriety be called fibres ; such are the ORGANIC STRUCTURE. 91 large fleshy roots of asparagus, (Fig-. 23,) and the like. These are evidently preservative appendages containing a store of nutriment for the use of that part of the crown to which they are attached. In fact they are only a modification of a tuber, but with this difference they are destitute of buds or of any principle of reproductive life, save that which they possess as an appendage of the crown. The fibrous roots and stems of shrubs and trees are increased in thickness together. Whilst the stem is receiving a new layer of alburnum, the roots also receive an addition of the same kind. It is from this circumstance that roots are known to be more enlarged toward autumn than at any other time of the year. Some practical men are of opinion that the princi- pal office of the roots is only to fix the plant in the earth. They infer this from observing that some plants live entirely in air ; that in the order Pan- danece and its alliances, the first roots only are pro- duced from the collet, and all the subsequent ones from the stem ; the roots of cuttings moreover are produced by the stem, protuberances are formed above^ wounds and ligatures; and there are many instances of accretion or enlargement of the inferior parts of plants, which is evidently received from the influence or action of the organisation above. Admitting that these instances are corroborative, to a certain extent, of the opinion above alluded to, yet, from the ordinary and well-known functions of the roots in supplying water and nutrition on all occasions to the head, it is impossible we can con- 92 ORGANIC STRUCTURE. sider these two divisions of the plant in any other light than as " correlative parts" necessary to the system ; and therefore by no means entirely inde- pendent, notwithstanding we often see them acting in the absence of each other : felled trees produce shoots, and the roots of trees and deep rooting herbs will continue to throw up sap for a long time after the head and stem are cut off. The Collet. This is that part of the axis which divides the stem from the root of a seedling. It is the seat of the cotyledons the crown of the roots and the base of the stem. It is certainly a dis- tinct member of the plant, especially in the early stages of life ; and has been so considered by many eminent botanists. Fischer and Treviranus call it centrum vegetationis ; Turpin termed it ligne mtdi- ane ; Professor Hayne of Berlin calls it nodus indifferentialis ; and Lamarck, and many others, the life-knot, (a. Fig. 8.) If a seedling of an herbaceous plant, and of many kinds of trees, be cut over below the collet, the root invariably dies ; but if above, except some kinds of Coniferce, Palmce, &c., the root will contiryie to live, and new shoots will be produced from the collet. Trees whose root, stem, and branches are studded with incipient buds, as the myrtle for instance, con- tain a much greater number crowded together in the collet than in any other part. It is on this account that portions of the protuberant part of it are chosen and planted for the purpose of propagating the olive, in the south of Europe. The nodes of jointed stems ORGANIC STRUCTURE. 93 are constituted (in respect of being- the seat of many buds) like the collet ; in the vine, for instance, the latent buds in the nodes appear to be inexhaustible. In the greater number of aged trees the collet cannot be discerned. This is particularly the case in such kinds as produce suckers. Others there are whose collet is protuberant with the remains of former shoots ; or accidentally, as we often perceive the Spanish chestnut to be on dry ground. The collet is in most cases the partition between the ascending and descending parts of the plant ; in bulbs it is the radicle plate ; of herbs and fusiform tubers it is the crown ; and in trees and shrubs it is called the collar or collet. (Fig. 27.) It is moreover the base of the pith, which is the central organ of the member which next falls to be described. Fig. 27. a, example of the collet as it appears in trees and shrubs ; 6, on fusiform underground stems; c, on herbaceous plants; and and as are those of aquatic plants in the mud, as Nelumbium specibsum\. Fig. 29. An aquatic plant extending its sterns in the mud. The bulbous stem has been already described. Tuberous stems, as the turnip, are casual enlargements of the pith, covered with the proper integument of the stem, but also greatly thickened and pulpy. This, as well as the incrassated stems of Dducus, Pastinaca, Beta, and others, are, for the most part, only the effects of cultivation. The tubers of Heli- dnthus, and Solanum tuberbsum , are the abbreviated and engrossed points of subterranean stems of the plants. Of such subterranean stems there are modi- fications, and they may readily be distinguished from what are properly called tuberous roots ; the former * Horse radish. ( Couch-grass. | Water-lily. Jerusalem artichoke and potato. ORGANIC STRUCTURE. 97 being- furnished with latent buds or viviparous prin- cipals, whence new plants are produced, while the latter are not. The JPcebnia furnishes an example of the tuberous root. Fig. 30. Ligneous or woody stems are composed of several distinct members which may be described in the order of their position, beginning with The Pith. This member occupies the centre of the stem, and constitutes the principal part of the bulk of the seedling, and of every young shoot. It is more or less filled with spongeous, cellular matter, divided into large longitudinal locoments, easily per- meableby the fluids of the system. (Fig. 1.) Although its apparent use is to strengthen the young shoot, and to act as a duct or reservoir of moisture, its structure and numerous hollow spaces show, that it may be also a chamber for containing an elastic gas, which when acted on by the heat of the air, must necessa- rily assist to distend and elongate the sheath in which it is contained. There seems to be no action in the pith (except as a duct) after the first year, for as it increases in age it decreases in volume ; and in old stems becomes almost obliterated. A thin sheath 98 ORGANIC STRUCTURE. of dense cellular matter encloses it, and to this the first concentric layer of wood is attached. In hollow stems pith is only found at the articulations ; and in jointed stems which are solid, the pith is interrupted at each joint. It is also somewhat interrupted at the base of every branch of a simple stemmed tree. The Wood. This member is simultaneously pro- duced with the pith which it surrounds. It appears in three different states during its growth. At first it resembles a semi-transparent mucus : next an inspissated jelly showing faint signs of organisation ; and last as alburnum, possessing all the fibrous structure, tubes, sap vessels, and other components of perfect wood. It is the lateral expansion of this mem- ber, and that of the pith, which increases the diameter of the seedling stem. During its growth it is the seat of the vitality ; but ceases to be so as soon as the summer growth is over. This is demonstrable by the fact, that the first formed concentric layer of wood ever remains of the same dimensions it acquired in the first year. If this first layer of wood be examined in the autumn, we find its exterior side formed of denser cellular matter than the interior ; the latter being- more porous, owing to its containing larger and a greater number of tubular openings. We can also discover radiating partitions of close cellular sub- stance perpendicularly placed, diverging from, or con- verging to, the pith, and dividing the ligneous layer into segments. These partitions are not so conspi- ORGANIC STRUCTURE. 99 cuous in the first concentric layer as they are in those which are afterwards imposed ; and are the glossy waves of the grain of timber exposed hy the plane, and so conspicuous in oak when cut into panels. This description of the growth of the cylinder of wood of the first year, applies to those of every shoot afterwards made by the tree, and also of every layer of wood which annually enlarges an old stem. The JBark. The next visible member of the seedling stem is the outer covering or epidermis, con- sisting of a thin colourless cuticle, inclosing a coat of parenchyma. It covers the plumula before its expul- sion from the seed, and continues for ever after on the exterior of the stem ; although, on the generality of shrubs and trees, it becomes so much distended by the internal growth, that its identity disappears. Another member of the bark starts into visible existence at the end of the first summer, namely, the liber. This is at first a part of that member described as the wood ; but is discharged therefrom at the end of summer, and then being distinct receives the name of inner bark or liber. The bark is an excrementitious part of the plant. It is increased in thickness every year, during the life of the tree, by new layers of liber added to its interior surface ; so that the numbers of layers of bark, like those of the wood, always indicate the age of the tree. This, though a general rule, has some excep- tions ; as exemplified in the Arlutus andrdcline and the Vitis vinifera, which plants discharge their outer bark every second or third year. H 2 100 ORGANIC STRUCTURE. In old trees it is only a few of the inner layers that participate in the vitality, or act organically in the system. All the outer layers serve only as a cover- ing: and these, if not thrown off, or cracked into longitudinal fissures, or stretched horizontally to make room for the internal accretion, actually check the growth and hasten the decay of the tree. Bark, in the generality of trees, is thicker or thinner according as the growth of the stem has been rapid or slow. Trees that stand singly, or on elevated situations, and consequently exposed to full air and every wind that blows, increase in diameter of stem and extent of branches much more in propor- tion than if they had been drawn up in close planta- tions or in sheltered places. Hence each year's layer of liber partakes of the character of the stem, not by an increase of number of layers, but by an augmented thickness of each. The leaves and other appendages of the bark need not be described here ; suffice it to notice only, that their expansion is cotemporary with the development of the other parts of the stem mentioned above. Pendulous stems. These are commonly called weeping trees ; and are exemplified in the Betula pendula, and the Salix Batylbnica. The young shoots, instead of being erect, obliquely or horizon- tally spreading, droop and hang almost perpendicu- larly. This is evidently a consequence of rapid growth and constitutional laxity. The erect position of the shoots of other trees depends on their mode- rate growth and rigidity. Those of weeping trees ORGANIC ' have not this stiffness of fibre at first, but gradually attain it as they advance in age ; each layer of wood added to the base of the pendent shoot brings it more upright ; hence it annually gains elevation : were this otherwise, a weeping willow would never rise from the surface of the ground. There are many instances of casual flexibility among plants, owing entirely to over-luxuriant growth. Every gardener must have noticed the dangling position of the strong shoots of Jargonelle pear, and other fruit trees. Underwoods, especially of ash, if after they are felled a favourable growing season follows, rarely make straight poles ; the weight of the shoots, with their ample foliage, bends them to the earth, from which position they do not soon recover. Accident has produced varieties of erect-growing trees, which have become horizontal or rather pros- trate growers, and art hath perpetuated them. Such are the weeping ash, and one variety of the white- thorn. It does not appear, however, that the hang- ing position and downward direction of the shoots of these trees proceed from laxity of fibre; because those of the weeping ash, particularly, are as rigid as if they grew upright. Grafts of these grovelling branches continue, though their seeds do not transfer, the deformity. Climbing or winding stems. A laxity of stem which would prove injurious to the maturation of the plant, is counteracted by their power of supporting themselves in the air by twisting round any other ORGANIC STRUCTURE. plant or slender body within their reach. This is a curious and unaccountable property. If all twining plants revolved in the same direction, something like a rational reason might be assigned as the cause; but, as some turn to the right and others to the left, it is obvious no extraneous agent can affect vegetation so as to produce contrary motions. It appears, therefore, that this tortive action results from a constitutional arrangement of the fibres of the stem, which may be supposed to be conjointly and spirally disposed round the pith or axis, and which, as they are elongated, continue to revolve by their tendency to become straight, while they are lengthened out. We see, at the same instant, an advancing and an involving or retrovolvant action of the stem ; and the only expla- nation of the phenomenon we can give is, that all twining plants, having their system of stem fibres coiled from right to left, turn to the right ; and those whose fibres incline from left to right, turn to the left during their growth. All this is assumed as a probable theory rather than a demonstrated fact ; for it must be confessed that, except the twisted or spiral position of the furrows on the surface, dissec- tions of these stems have yielded no corroboration of the opinion. The spirally lying position of the fibrous structure of stems, and the spiral vessels found in young shoots, roots, petals of flowers, &c. are evidently organs having a mechanical action to assist in the elongation or expansion of the cellular tissue in which they lie imbedded. In this character these ORGANIC STRUCTURE. 103 vessels operate to regulate the expansive force of the distensible membranes of the system under the influ- ence of heat, air, and light. This is not only very visibly the case in twining stems, but also in some others which have aspiring, though not involving, powers. We may instance the larch which, when young and growing rapidly, has not only a wavy* form of stem, which, however, it loses when old, but, when cut up for use, retains this twisted structure so much that it is impossible to keep the scantling in a square or rectangular position, until it has been thoroughly seasoned. Another remark may be made relative to climbing perennial stems. They are seen to rise perpendicu- larly so long as they have any thing to cling to ; but when they have surmounted the prop their tendency to rise seems to undergo a change ; because they never afterwards grow with such rapidity either horizon- tally or downward, but become bush-headed. Creeping Stems are well exemplified in the strawberry and many species of Graminece. Progressive growth. Having noticed the com- ponents of the ligneous stem developed in the first year, by which it gains elevation and increased dia- meter by the inflation of its cellular and vascular * The structure of the wood of many trees has a wavy character. This is not only visible in the grain of oak and other indigenous trees, hut it constitutes the principal value of some foreign kinds especially that called satin-wood among cahinet makers. 104 ORGANIC STRUCTURE. membranes, each member being- impelled into definite order and position according to the natural constitu- tion of the plant ; we come now to describe the pro- gressive growth of the second and third years, which with figures of cross and perpendicular sections of the stem in each year, will give as perfect an idea of the constituents and their transformations as the writer is able to convey. Trees are dormant in winter; throughout that season no change whatever takes place in the dis- position of the components of the stem. Every member remains exactly as it was left at the time the growth of the previous year ceased. On the approach of the higher temperature of the spring, vegetable life receives a new impulse, the buds burst their hybernacla*, each shoot is elongated, leaves are expanded, and, perhaps, flowers, and the embryo fruit are displayed. The summer perfects all these, the autumn again arrests the growth, the leaves drop, and the whole plant returns again to its winter repose. Such as have not produced their seed would, if the summer were prolonged, continue to grow till that purpose of their being took place ; but those that have yielded fruit, or passed the period at which it should have been produced, make a pause inde- pendent of the heat of the season. The common ash is an instance not only of late vegetation, but also * Winter covering. ORGANIC STRUCTURE. 105 of early stagnation ; so that although the genial heat of spring revives the dormant plant by liquifying and giving intestine motion to the sap, yet the continu- ance of the growth does not entirely depend on tem- perature. Every hardy plant in this country has only to perfect the shoots, flowers, and fruit which had acquired a certain stage of advancement in the preceding year, and to bring the succession buds to a like stage in this. So in tropical countries the Enkianihus quinqueflora, and the Bombax celba shed their leaves in November, and develope new foliage again in March, notwithstanding the heat of the air is certainly never less than 60. All this goes to prove that the growth of many, perhaps all, plants proceeds by periodical impulses ; their sap being copious or deficient, or transmutable from a thicker to a thinner state, according as the weatner, the season, or the state of the plant requires. When the winter repose has taken place, if we examine a transverse section of the second year's shoot, we find it in every respect like that of the seedling ; and if we now look at a cross section of the latter, i. e. the first from the seed, we find it composed of a pith, two concentric layers of wood, a new one formed on the outside of the first, and also a new liber formed within that of the first year ; the cuticle and epidermis still continuing unbroken on the exterior of the whole. Again, in the autumn of the third year, if we examine a cross section of the third or topmost shoot, we shall find it similar to ITJII7 106 ORGANIC STRUCTURE. that of the seedling- already described, The second shoot will be like that of the first in the second year, viz. the pith, two layers of wood, and two layers of liber, covered by the epidermis. And if we cut and ex- amine the bottom, or first shoot produced by the seed, we shall find it consist of the pith somewhat dimi- nished, three layers of wood, and three layers of bark, besides the epidermis. It is scarcely necessary to add, that three seedling- plants raised together afford proof of what has just been stated. The following are representations of transverse and vertical sections of the seedling stem in the first, second, and third year of its growth, Pis. 31. fill! First year magnified. Fig. 32. ORGANIC STRUCTURE. Fig. 33. 107 11 Third year. These examples of the annual accretion of the stem for three years will suffice to show the manner of all subsequent growth ; for, in fact, an oak of a century old (if not decayed at the heart) will be found composed of one hundred layers of wood and one hundred layers of bark, whether they are dis- tinguishable or not. The zones of wood are more visible in some kinds of trees than others. Slow growers have their layers so closely posited on each other, that they are very indistinct ; and in the case of the oak and some others, they appear twinned or double, owing no doubt to the spring and midsummer growths usually made by these trees. The same observation may be made of the bark ; the layers of which are so extremely thin that they are not easily identified. It often occurs that on viewing a cross section of a felled tree, the pith is not exactly in the centre, where it would be did the tree swell equally all round. This irregularity proceeds from various causes ; sometimes from the roots being better 108 ORGANIC STRUCTURE. nourished, or from there being more branches on one side than on others. Sometimes the south, in other instances the north side is most prominent. The under side of leaning trees, and of all branches, are extended further from the centre than the upper side*. A wound on one side will determine the greatest share of the growth to the opposite. Fig. 34. Example of the manner in which a wound received in the fifth year is healed. A transverse section. Neither are the annual layers equal in size ; some are thicker than others ; caused, no doubt, by uncom- monly favourable seasons ; a tree makes more pro- gress in a moist and warm summer than in one that is cold and dry. There is also difference in the thick - * This is attributed by some physiologists to the effect of gravi- tation on the fluids ; others imagine that the upper side being more exposed to ai and light, the sap is thereby exhaled away more rapidly, and consequently the tubular structure is less distended. ORGANIC STRUCTURE. 109 ness of the layers according to the age of the tree ; when very young or very old the layers are less than when the tree is in vigorous youth. From the time each individual layer conies into visible existence till the period of its decay, it under- goes some very material changes. When first visi- ble it is called cambium, and next alburnum by botanists ; and by woodmen and carpenters the sap- wood. In this stage it forms the principal channel for the flow of the sap ; but after a certain, or rather an uncertain number of years, it becomes changed in colour and consistence, and henceforth is called per- fect or heart-wood. In some trees, as the beech, the wood soon gains perfection. The oak has generally six or seven, sometimes more, layers of alburnum or sapwood, and all the interior perfect. The change appears to be caused by the white wood gradually ceasing to be a channel for the con- duction of the sap ; and to a certain chemical action by which its colour and texture is changed from a white and soft, to a brown and harder consistence. The sap also, which becomes secreted in the intercellular spaces and vessels of the mature wood, assumes a concreted form and acts as a cement to the fibrous structure. As different kinds of trees have wood of very dif- ferent degrees of hardness and durability, the follow- ing questions occur ; does the durability depend on the texture or density of the ligneous structure, or on the quality of the concreted juices therein 110 ORGANIC STRUCTURE. contained? It is said that if Brazil wood be deprived of its colour by any solvent, it loses also its strength and ponderosity. In the case of fir timber, it is very evident that its durability is entirely owing to the resinous and slowly exhalable quality of the sap. Many kinds of timber, as beech, for instance, if kept constantly under water, so that its natural sap be not dissipated, will last for many years. Ash, when arrived at maturity, is as tough under pressure, and solid under the tool as the oak; but it decays much sooner in the air ; the durability of the latter must therefore depend on some inherent quality not possessed by the former. Now as the oak contains an extraordinary quantity of an astringent principle, may not this be the preservative matter ? On this point an inquiry should be instituted, whether that scantling of oak containing the greatest share of this astringency be or be not more durable than a similar scantling containing less. Another inquiry should be made ; whether one description of soil produces oak timber of superior quality as to durability than another, and what is the difference of these soils. It is well known that the most stately oaks grow on deep loam reposing on a clayey subsoil ; but the durability of the timber, and the constituents of the soil, have not been, perhaps, sufficiently compared. Some soils are bland and composed of simple earths ; others, viz. clays, loams, and gravels, are strongly impregnated with ferruginous qualities, which may ORGANIC STRUCTURE. Ill materially affect the properties of the timber pro* duced upon them. For several years past there has been great com- plaint of the deterioration of oak timber, especially in the dockyards. Compared with oak beams in ancient buildings, that of modern growth is absolutely worthless, falling a prey to dry rot before the ships built of it have been launched from the stocks ! Its inferiority has been attributed to want of age, to arti- ficial cultivation, to want of seasoning, to the wrong variety being planted, and to the more general pre- valence of dry rot. Whether any of these circum- stances may have been the cause of the deterioration, is not clearly ascertained ; but it is more than pro- bable, that the quality of the soil whence the trees have been felled, if duly investigated, would show the true reason of the deterioration. The layers of many years form aggregately the body of timber which, in all its stages, has an obvious longitudinal arrangement ; splitting most easily from top to bottom, and in right lines through the pith ; and also readily in the direction of the sides of the layers, which separate from each other with ease. These concentric layers are only attached to each other by fine cellular matter, but without any inter- junction of their fibres ; the diverging partitions, which proceed in right lines from the first layer to nearly the outside of the bark, appear to be the connecting ties which keep the whole together. In 112 ORGANIC STRUCTURE. whatever way the wedge is introduced, it is the cellular matter that yields in the cleavage. By no power can the trunk be cloven transversely ; the fibrous structure opposes all efforts to separate the wood across its position. The longitudinal strength, common to all woody stems, appears, however, to be in some plants acquired by age. The grape vine is an instance among trees of a peculiarity in the structure of the stem when very young, namely, that the longitudinal arrange- ment of the fibres is interrupted at every joint, part- ing easily at the nodes, leaving a clean surface on both divisions. This shows that the first layer of wood is somewhat articulated, and has less longitu- dinal connection and tenacity than those which are afterwards imposed. The woody fibres which give strength and tough- ness to the layers are united irregularly with each other ; in young shoots which have just commenced growth, some of the fibres, especially in the medullary sheath, are seen disposed in single or double coils, which become almost straight when lengthened out in the growth, and the whole then appears (when the layer is split through the middle downwards) like the meshes of a net, when intensely stretched in one direction. No spiral vessels are found in perfect timber; because the single or double fibres which formed them are then disposed at full length. ORGANIC STRUCTURE. Fig. 35. 113 Spiral fibres found in young shoots, petals, and points of some roots. These spiral vessels, or rather ligneous fibres spirally disposed, being seen only in young shoots, leaves, petals, &c. which are in the act of elongation, and never after the longitudinal growth is over, may be conceived to act mechanically, as before observed, in the evolution of the shoot ; or, if not, we must ad- mire the natural disposition of a fibre, of perhaps a foot long, so coiled up in a bud before its expansion. If we examine a single fibre with a glass we gain no very clear idea of its conformation. However carefully separated from the mass, there remains ad- hering to it a crust of the cellular matter which unites the fibres together, so that its structure is thereby obscured. But it evidently has an identical character, of which its toughness and elasticity are sufficient proofs. Physiologists who have employed micro- 114 VEGETABLE SAP. scopes of the highest powers, describe the ligneous fibres as being formed of " elongated cells attached by their ends to each other." Solly. The Sap. The sap of plants is that fluid which fills and assists to distend the cells and vessels. It is of various consistence ; in some plants it is thin and watery, easily congealed by cold and evaporated by heat ; in others gummous, and in many resinous. Besides the difference in consistence, the sap contains many essential qualities, as sugar, starch, resin, &c. with a thousand combinations of these and other bodies in various degrees. The juices become inspissated and almost stagnant during winter or when the plant is at rest, and regain fluidity and motion on the return of spring, or of the growing season. So completely fluid is the sap soon after the commencement of the growth that it flows freely from wounds. During summer its excess is consumed by the lengthening shoots, numerous leaves, and swelling fruit. In autumn it becomes gradually thickened in consistence, and is at last again arrested in its motion by the cold of winter. It is often ob- served, however, that in the last mentioned season, even after the leaves of deciduous trees have fallen, and all outlets of the growth shut up, that a few warm days will so liquefy the sap, that it will again flow from wounds ; more especially if the roots are in a moist situation. That the peculiar qualities and characteristics of the sap are elaborated by the plant itself, as has been VEGETABLE SAP. 115 before asserted, is perfectly notorious. To no pur- pose do we analyse the soil in which it grows, or the water with which it has heen nourished, to detect the qualities which are found in the root, stem, or leaves, much less in the fruit. It must be remembered, that in the areolated structure of vegetables all the appa- ratus of the chemist's laboratory are found : alembics, retorts, and all the natural machinery for absorp- tion, nitration, condensation, and assimilation of aqueous, vaporous, and gaseous bodies of the earth and air, are silently and constantly in operation, and the results are the production of the essential qualities of the plant. In all the living members of a tree, as in the seat of life, the recently formed layers of liber and alburnum, the sap is capable of motion ; but in those members which have already performed their func- tions, and acquired form, namely, the outer bark, and first formed layers of wood, it becomes concreted and stationary. While capable of motion it usually ascends, is transpirable, and consequently exhaustible. In the latter case, the leaves and tender shoots become flaccid and shrink; but when the exhausting cause is withdrawn, or a sufficient supply of water is re- ceived by the root, the shoots ^nd leaves quickly regain their rigidity and vigour. This single incident is a convincing proof of the ascent of the sap ; nothing indeed can be more manifest. That the repletion of the sap vessels is kept up by the agency of the roots and other absorbing organs of 116 VEGETABLE SAP. the system, scarcely admits of doubt. The ascending current may be exhibited to the naked eye by the well known expedient of supplying roots with co- loured liquids, as has been proved by Darwin, Knight, <&c., and every florist knows that the colours of flowers may be changed, and the bulk of all the parts increased, by the application of suitable manures. Much ingenuity has been shown, and the most laboured philosophical dissertations have been written, to account for the ascent of the sap, one of the most simple processes in nature. For surely, if a bit of sponge, or any tissue of filaceous matter be capable of imbibing water to any height, no doubt need be entertained of the power of vegetable organisation, with its myriads of cellular and intercellular ducts and tubes, to do the same. The elongation, disten- sion, or inflation of any tube, cell, or vessel, in the extended head, must necessarily produce a vacuum which is instantly filled up. The pressure of the atmosphere, capillary attraction, or simple imbibition of areolated substances, are all ordinary agents capable of effecting this result. The like effect takes place in an old oak gate-post; and why should not the hydraulic action of the extending shoots, the perspiring leaves, and the craving fruit, produce a similar result in living plants ? It would be a waste of time to insist farther on such an obvious truth ; for, in fact, the ascent of sap may not inaptly be compared to the common evaporation of all fluids under the action of heat. VEGETABLE SAP. 117 It has been observed above, that after an uncertain period portions of the trunk cease to partake of the diffusive current of the sap, and in those effete members it becomes concreted. In this state it is very visible in fir timber, reposing in knots and flaws, and oozing out of the pores, when exposed to heat. When chips of wood are submitted to maceration in a proper menstruum, the secreted sap is first dissolved, next the cellular partitions, and at last the woody fibres are decomposed *. Although the natural motion of the sap be from the roots to the extremities of the branches, there is no doubt of it being occasionally transfusible in all directions. Wherever there is depletion, thither will the current be drawn; whether that be upward, laterally, or downward. Whatever the position of the branches may be, we see the sap courses along them to reach every extremity. With respect to the old popular belief that the whole body of sap regularly and annually retires to the roots in winter, there to remain till the genial warmth of spring again prompts it aloft, we may ob- serve that the doctrine rests on no very solid founda- tion. The vessels of the roots are never at that * season so destitute of sap, nor have they capacity * In the case of pine or fir timber it is observable, that where the cellular structure is most dense, as on the exterior sides of the concentric layers, these portions are more durable than the inter- mediate spaces. The medullary rays of these trees, though numerous, are extremely thin. 118 VEGETABLE SAP. enough to admit such a surcharge. The sap in the branches is not visibly diminished by this supposed subsidence ; and what is more against the idea than any thing else, is the stubborn fact, that the motion of the sap begins at the top of the tree before it is at all liquefied at the bottom, which could not happen did the returning tide flow from the roots. The best argument in support of the subsidence of the sap is that used by the carpenter respecting the quality of winter and summer felled timber: but this will be answered under the section Felling. We may, how- ever, observe here, that if there were any apparent necessity for such subsidence we ought, unhesitatingly, to concur in believing it. We are well aware that those who believe that the elaborated sap descends, also be- lieve that it is chiefly disposed of in the formation of the new zone of wood along the whole length of the stem and roots ; so that the carpenter's idea of it all sinking to the roots is abandoned: but, if our eyes have not greatly deceived us, we have observed that this same new zone of wood is formed and replete with sap, before the time arrives at which the sap is said to take its downward course. And, indeed, ex- cept in the case of herbaceous perennials (admitting the opinion true with respect to them) it appears to us, that the subsidence of the sap, in other cases, is superfluous, and contrary to the usual operations of nature. Upon the whole we are led to conclude that the sap is composed of fluids chiefly imbibed by the roots ; VEGETABLE SAP. 119 that its specific qualities are acquired from the pre- existing- essentials of the plant, and from the elabo- rating- powers of the organic structure under the action of air, light, and heat ; that, whether as liquid or as vapour, its motion, generated by heat, must necessarily be upwards, if not impelled or attracted in any other direction. Whether it be capable of sink- ing- by its own weig-ht is, perhaps, questionable ; because there must be a vacuum somewhere to receive it, or it must displace some other fluid which must ascend out of its way, and the tubes containing it being all sealed at the top, prevent the perpendi- cular pressure of the atmosphere ; and though true, that when abundant and fluid, it distils from the upper side of a wound as well as from the lower, yet it con- tinues to ooze away from below longer than it flows from above, whether the wound be made in the spring or in the autumn. Example, a felled tree: while the dissevered butt of the stem is quickly dried, the root remaining in the ground, will continue to bleed for months after jthe separation. The sap, therefore, besides its direct motion, is capable of being- diffused through the whole body of cellular and vas- cular matter, and of course flows towards any outlet? whether that be aspiring shoots, perspiring foliage, swelling fruit, empty vessels, or bleeding wounds*. * A curious instance of the counter currents of some component of the sap is observahle in the common aquatic plant Chara* Bright globules are seen to rise and fall in the vessels, exactly simi- lar to what is seen in fermenting liquors. 120 VEGETABLE SAP. Like other fluids the sap of trees flows quickest in right lines. This is well known to the pruner and trainer; who, by curving- or reversing- the leading shoots, checks their luxuriance. It flows, however, with greater celerity perpendicularly than in any other direction. While the sap is stagnant in the branches, it is also so in the roots, but with this difference, that in the latter it is always fluid, owing to the higher tempera- ture of the soil, and consequently, is ever ready to rise as soon as the channels in the stem are open. In mild winters (perhaps in all winters) there are signs of life visible in the slowly swelling buds, and exsertion of new fibres from the roots. The sap has been supposed to be transmutable into cambium, and ultimately into wood ; but this requires confirmation ; because, if sap be exuded from a wound, it takes either the appearance of gum, as on the cherry, or sanies, as on the elm ; but, when cam- bium is protruded into air, it immediately assumes a ligneous character. Besides, if sap be capable of transmutation so as to be indurated by chemical agency into timber, why is it not seen to be so changed in the interior of stems, where it is found hardened indeed, but perfectly homogeneous and free from every sign of organisation ? It is said that elaborated sap descends from the leaves down the bark, and is thence attracted inwards to the centre of the tree; but this being an invisible process and caused by agents unknown to, and out of the reach of, mere VEGETABLE SAP. 121 practical observation, disqualifies us from either as- senting- to, or denying- what can only be a plausible supposition. It is also said that flowers and fruit are formed from accumulations of elaborated sap. For instance, if a tree, or a branch only be " ringed," the matured sap thereby pent up and prevented from sinking to the lower parts, is expended in the pro- duction of flowers and fruit ; thus attributing to the sap the property of conversion into organs. Were it only inferred that perfect juice is necessary to the sustentation and expansion of flowers and fruit, the idea would be reasonable ; but that organic structure can be spontaneously formed from a mere fluid is wholly incredible. The foregoing observations concerning the pro- perties and motions of vegetable sap, being very diiferent from the usual notions entertained of it, the writer hopes to be excused if he occupies another page or two of remarks, by way of justification of himself for thus differing so much from the opinions of his cotemporaries and professional brethren on this important part of vegetable physiology. A full explanation is the more necessary on his part, because the belief of the annual descent of the sap is not only, as before observed, a very old idea, but also because it serves to explain several circumstances occurring in the growth of plants, which cannot be otherwise accounted for. The writer does not deny the possibility of occasional or partial sinkings of the sap ; on the contrary, he is fully convinced of its 122 VEGETABLE SAP. diffusibility through the cellular and vascular struc- ture in all directions ; but that the sap should retreat in a body from one set of vessels, which, notwith- standing, are not emptied, and proceed to others that are already full, is extraordinary ! If we consider the motion of fluids in general, and in all ordinary circum- stances, we invariably observe that their motions are caused by their fluidity, ponderosity, or temperature ; if they flow from a place which is full, it is because there is a vacant space to receive them : a rarer fluid will give place to one that is heavier ; and conse- quently the warmest parts of a fluid will rise above those which are colder. But in all these cases an outlet or vacuum must exist, or the removal of some pre-occupying fluid must take place before any mo- tion can be generated. Now, we presume no prac- tical eye has ever discovered that roots are more charged with sap in winter than they are in summer, nor that the topmost shoots are sapless during the former season. If it be urged that the lower tem- perature of the sap in the branches is the cause of its subsidence to the roots, it may, with equal reason, be asserted, that the warmer portion in the roots will be propelled aloft by such subsidence, and that an equilibrium will be always maintained. But it is further quite manifest, that if there be any descent at all, it not only takes place in the autumn, but is in operation all the summer ; because one of the principal proofs of the descent of the sap, namely, the swelling of a stem above a ligature, becomes VEGETABLE SAP. 123 apparent early in the summer, and therefore is as valid proof of descent in the month of May as in September or October. Bulbs, tubers, and tuberous roots begin swelling- early in the season, and continue increasing till the growth ceases in the autumn ; consequently there must be something like a current down as well as upward. This is, however, one of the most inexplicable phenomena in vegetable economy. It is quite evident that all the parts of a plant, root, stem, and head, are enlarged together during the summer, and mainly by the nutriment taken in by the roots, and which food, of course, ascends to the parts above and descends to the parts below the roots, as in the case of potatoes. In watching the gradual enlargement of the stem, we cannot avoid observing, that there is a processional maturation or enlargement of the parts, beginning, as it were, at the top, and proceeding downward, not only to bulbs and tubers, but to the fibrous roots of trees also. In order to have a clear understanding of this curious circumstance, it is only necessary to state the facts as they occur to practical observation : If a shred remains too long in the same place on the stem or branch of a trained tree, it causes constric- tion, which not only obstructs the growth of the part covered, but produces an unnatural prominence on each side of the band, and much more above than below. (Fig. 36.) This result shows that some com- ponent or internal motion of the plant is obstructed 124 VEGETABLE SAP. Fig. 36. in its course from the extremity of the branch to the root. Similar protuberances are found at the lower end of a graft or bud that happens to be placed on a stock of more diminutive organisation. (Fig. 52) ; also Fig. 37. VEGETABLE SAP. 125 above the base of every branch of a tree ; or round a place whence numerous shoots have been repeat- edly browsed off (Fig. 37). Beech and elm trees frequently present malformations of this kind; some- times by large tumours formed within the bark united to, and being projecting parts of, the woody axis, and occasionally by insulated portions of lig- neous matter involved in the bark and easily separable therewith. The same kind of protuberance is often formed at the base of cuttings previous to the ejection of fibres (Fig. 38) ; and also round a wound on a Fig. 38. stem, particularly at the upper side (Fig. 39). Such accidental eruptions on old trees continue to be enlarged for many years, and receive annual additions of bark and wood, like any other part of the trunk ; 126 VEGETABLE SAP. Fig 3.9. \ their form being generally oblongly round, but in- creasing downward much more rapidly than in any other direction. (Fig. 40.) Fig. 40. A protuberance on an elm. When these protuberances are laid open, we find them composed of either cambium on their first appearance, or of ligneous material after they are six months old ; and evidently dilatations of the vital VEGETABLE SAP. 127 envelope. Some former, and many modern, botanists consider these callosities as no other than obstructions of the returning- sap ; others conceive that they are fibres projected from the buds and shoots above, which are arrested in their progress down, and accumulating above the constriction cause the distortions in question. From many and repeated observations made on the effects of ligatures on various sorts of trees and shrubs, and daily in view for several years past, it is quite evident, that the swellings, both above and below, beg-in to be visible very soon after the spring- growth commences ; and that they appear to be nothing more than that part of the vital membrane confined by the band, venting- itself above and below, and forming- the protuberances alluded to. If a single wire be used, the swellings on each side are nearly equal : if the band be of the usual width of a shred, the prominences on each side are nearly equal on some trees, but on others that on the upper side is considerably larger than the one below. (Fig. 36.) It is quite obvious, that if there be a procession of either sap or fibres from the superior to the inferior parts of the stem, a ligature would certainly produce a swollen margin on the upper side ; and did the tumour at any time of its growth contain simple sap only, no doubt would remain of the cause ; but this is never the case ; the interior is invariably found to be either imperfect or perfect wood, that is, either cambium or alburnous matter. This, indeed, to those who believe that the sap is " organisable," is BO 128 VEGETABLE SAP. mystery ; but as it is easily proved that cambium and sap are two very different components of the plant, and moreover that no direct proof has yet been had of the descent of fibrous matter from the buds downward, we are compelled to pause before we can confidently ascribe the cause of the tumours to either the descent of the sap, or to ligneous fibres from the superior buds. But if neither sap nor fibrous matter produce those appearances, what else can it be ? We have already said, that the circumstance is inexplicable ; and it would be uncandid and inconsistent with our regard for truth, did we not frankly acknowledge our ina- bility to explain the phenomenon. Mere supposi- tions would be impertinent ; and it is, every way better to leave such a matter open by recommending it to the consideration and scrutiny of others, than obscure it by fanciful conjectures. The only circumstances which appear analogous to the downward action observable in this case, are, firstly, the manner of flowering of the genus Liatris. and some other plants. Instead of the flowers opening from the bottom of the stem upwards, they begin at the top, and blow consecutively downwards. Secondly, the culms of wheat, and other corn ripens, or rather dies, from the ear downwards ; so that the seeds are ripe before the vital action ceases at the bottom, and whilst the crown is yet throwing up fresh stems. Thirdly, the spring motion of the sap begins at the points of the branches. This fact has led some most VEGETABLE SAP. 129 intelligent practical men into error ; they conceiving that instead of the sap rising, as it is known to do, it actually descends I Now, a moment's considera- tion might convince them of their mistake. The sap undoubtedly begins to be fluid and first in motion at the top of the tree ; that immediately below is next liquefied, followed by that lower still, and so down lower and lower till the whole that in the root also is in full motion. We have elsewhere ( Gard. Mag. vol. vi. p. 214), compared this circumstance to the sudden opening of a full canal at one end : thus opened, the water flows oat ; the current begins at the outlet, and is generated backward till the whole is flowing. This is exactly similar to the first spring movement of the sap of trees, and presents the appearance of a motion directly contrary to its true course. Whether the maturation (if we may use the term) of the cambium into alburnum, in the latter end of summer, takes place in the same order, that is, begin- ning at the top and ending at the root, remains to be proved. The fact of roots being more enlarged during autumn than at any other period of the year, is some corroboration of the supposition ; still the question is not free from doubt ; because the idea presupposes that this change of cambium into albur- num is only a descending effect, not a positive pro- gression downward of any actual member or compo- nent of the tree, and therefore unsatisfactory, unless we could prove that the full expansion of every inferior cell depends on that of the one immediately K 130 VEGETABLE SAP. above it. Besides, if this downward motion be only that of an effect on the cellular structure, why should a bandage prevent the expansion of the structure of the stem, as well below as above the band? The subject is every way intricate, and requires investigation. We have made many experiments to ascertain the cause, but without success. All our conclusions have been negative rather than affirma- tive of what we expected what it is not, rather than what it really is. For instance, we observe that the new zone of wood formed in the course of summer, begins to be visible at the bottom of a lofty tree nearly as soon as it is on the highest branches, though we cannot vouch for its being as soon perfect. This being the case, we doubt whether any fibres specially attached to, and descending from, the expanding buds and lengthening shoots, can possibly reach so far down the trunk in so short a time as elapses between the bursting of the buds and appearance of the new alburnum so far below ; nor can we admit that there is any gradual descent of fibres in the course of several years that is those belonging to the buds of 1827 gaining, or reaching to the base of the trunk in 1831, or in any subsequent year. We know this to be impossible, as will appear by referring to Fig. 48, page 145. Another thing the longitudinal connec- tion and arrangement of the fibrous structure of each zone of wood, is so entire from top to bottom, that, on examination, we can arrive at no other conclusion than that the whole is simultaneously produced. VEGETABLE SAP. 131 We are authorised to state the result of an expe- riment which we had the pleasure of witnessing two years ago, viz. : Mr. Knight, of the Exotic Nursery, King's Road, Chelsea, believing that the sap, after being elaborated, obeyed the law of gravitation, and in subsiding caused the swellings on strangulated branches, fixed ligatures on the stems of a good many plants in pots, which were reversed on a stage made for the purpose. Fig. 42. In this unnatural position the plants grew well : the swellings, however, caused by the bands, were on the same side as if the plants had stood upright, namely, on that nearest the top, showing, as Mr. Knight properly observed at the time, that the prominences are caused by some internal movement or constitu- tional power of the plant entirely independent of position. The effect, whatever may be the immediate cause K 2 132 SEAT OF VEGETABLE LIFE. of these protuberances, is evidently similar to those callosities formed at the base of cuttings, and therefore it may be said to be an effort of the vital envelope to produce new roots, instead of those from which the communication is partially cut off by the ligature. But admitting this, we are still in the dark respect- ing which component it is that is thus obstructed in its course. We might, indeed, bring forward a very plausible idea of a modern writer to account for this processional movement down the stems of trees, which he attributes to the descending electrising principle of the sun's rays ;" but we fear to quote, lest we should err in referring to what we do not clearly understand. The seat of vegetable life. Every developed mem- ber of a tree is imbued with the vital principle in its early existence, and retains it while in the act of ex- pansion, but no longer. The bark is an exterior, and the wood an interior increment ; both have been in- flated into form, and forced into position by the life ; but as soon as the form is complete, and the position imposed, they are deserted by it, and when they cease to partake of its influence entirely they succumb to decay. Nothing shows the truth of this more de- cidedly than the circumstance that if a tree were divested of all its coats of bark but one, viz. the liber, it would continue to live and even prosper ; and were it possible to take out from a trunk the pith and al} the concentric layers of wood save one, viz. the albur- num, the tree would nevertheless continue to live SEAT OF VEGETABLE LIFE. 133 and increase in size, though the cavity would never again be filled up. There are, therefore, it is necessary to repeat, two states or degrees of vegetable life which should be described in order to be distinguished from each other, to avoid confusion of terms or ideas. The first is always present in those members which are capable of amplification, or are in the act of accretion, i. e. ex- panding from a small to a larger volume. The second is that state in which it is only conservative, but without the power of further growth of the mem- bers preserved by it. The first it is deemed proper to designate by the name of vital envelope^ whence proceeds every new member of trees, shrubs, and many herbaceous plants. The second is that state of the bark and alburnum which, having but recently come into full form and magnitude, serve as conductors of the fluids of the system for a certain time, but from which the actual life has for ever fled. Where then does the living principle reside ? In the pith ? no : in the wood, or in the bark ? no, in neither of these, but it is always found at all times be- tween the liber and the alburnum, slightly attached to both, but united to neither : it is reasonable, there- fore, to conclude, that it is a distinct member of the system. Of these opinions it is necessary to bring forward proof; and in order to do so satisfactorily, we have only to trace the phenomena of vegetation through the spring' and summer growth of a tree of a few years old. 134 SEAT OF VEGETABLE LIFE. The growth of young shoots and their components has been already described ; here we are about to attend to the manner in which this takes place. On the approach of the vernal warmth, the first sign of vegetation is observable in the swelling buds. At this time the sap which, for the most part, remained in a motionless and inspissated state during winter, becomes fluid and readily flows from wounds made through the bark. The narrow space between the alburnum and liber contains a copious flow; the latter appearing completely separated from the former. Soon afterwards, as the season advances, shoots are prolonged, and the foliage expanded ; the sap flows less freely from wounds ; a new body becomes visible in the space before mentioned, and begins to assume a lymph-like state denominated cambium. In this substance there is yet no appearance of organisation. The organs are then so diminutive and colourless, that neither their form, relative position, nor attach- ments can be detected, even with the assistance of the microscope. Mean time the bark is obviously giving way to the expansive force of the swelling cambium, and towards autumn, when the growth becomes lan- guid, the cambium has acquired considerable consis- tence ; the organisation is now visible, and very soon assumes all the appearance of perfect alburnum. At this time too, we find, that a new liber is separated from the new body of alburnum, and remains closely pressed against the liber of the former year. Now, whence have these new layers of wood and inner bark derived existence ? They are not a dilata- SEAT OF VEGETABLE LIFE. 135 tion of the last year's alburnum ; because that remains precisely of the same form and dimension it had at the end of the preceding- year. Neither has it sprung from the liber ; because that also remains unchanged, and is in fact superseded by the new one within it. As then they are not parts of the members with which they were and are in contact, they must either be self-generated from the fluids of the system by the assimilating powers of the plant, as has been by many supposed, or from some vital member which has been hitherto overlooked, or probably misnamed by physi- ologists. That such organised matter as that of bark and wood can be formed out of any possible accumulation of gaseous, aqueous, gumrnous, or even resinous fluids, or from their qualities, is extremely question- able. We cannot conceive that the beautiful arrange- ment of fibres, tubes, cells, and all the other structure of the vegetable fabric can receive specific disposition fortuitously. There must be a pre-existing organised body whence such regular formations proceed. The beautiful forms and results of crystallisation are indeed astonishingly admirable ; but they are generated by chemical associations, and obey other laws than those which govern vegetable development. That chemical agency is present in all vegetable processes is very probable, not, however, in such potency as to create forms and vital substances, farther than assisting the exhibition of them. It may be concluded, therefore, that the new layers 136 SEAT OF VEGETABLE LIFE. of bark and wood proceed from a member which, from its having- been erroneously identified with the liber or alburnum, has escaped observation merely from its unobvious identity^ and the small space it occupies in its dormant stater It may be best distinguished by considering it as being the inner viscous lining of the liber, and in this position and character it appears during winter as a very thin layer, scarcely distin- guishable from the liber itself. That this thin body or indusium is really the seat of life, the following circumstances may be urged as proof; and as they are constantly occurring to the practitioner in the propagation of trees, are the more to be depended upon. In the first place we may notice that no fibrous roots are ever produced from the wood or bark in any stage of their existence ; nor do buds ever origin- ate on the bark or wood, except from the first layer which surrounds the pith in the first year of its visible existence ; and which layer, be it remembered, is then in the act of swelling into form, and consequently part of the vital envelope. If a cutting be put in the ground, the first change it undergoes is a visible pro- trusion of cambium from between the wood and the liber, and from which in a short time fibres are ex- serted that become roots. So in the case of layers, the roots all proceed from those parts of the incision where this living member is exposed; and even where no incision is made fibres will be produced, apparently from the bark, but, in fact, originating SEAT OF VEGETABLE LIFE. 137 from its inner surface. When a bud or graft is placed in or upon a stock, it is the interjunction of the member between the wood and the liber of each which forms the union. As this vital member is the depository whence all roots proceed, so is it the seat of all incipient buds, and even of flowers. When the Cercis siliqudstrum has a branch pruned off, the wound is healed in the usual way, not by an extension of the old bark or liber, but by the vital envelope gradually closing over it ; and during its progress perfect flowers are ejected from it as well as from the clefts of the old bark. Buds we often see sprouting from the fissures of the bark of old trees, or brought out by pruning or decapi- tation. A truncheon of a willow placed in moist soil, a cutting of a myrtle, or a piece of the root of white- thorn, planted in favourable circumstances, will all produce shoots from the latent buds contained in the vital envelope. In short, no accretion whatever ap- pears, or possibly can appear, of any other member of the plant, save from that one we have endeavoured to describe*. It is further manifest, that this slender body of * As further proof that huds originate in the indusium, it may be remarked, that, in the case of hollow elms, if the wood be en- tirely decayed, and part of the last-formed layer of alburnum removed, so as to expose the interior side of the vital member, inside shoots will be produced therefrom, and rise within the hollow trunk. 138 SEAT OF VEGETABLE LIFE. vitality is constitutionally compound, not simple, as such a thin tissue may be supposed to be. That it is annually divided into three portions is perfectly obvious by ocular demonstration. In early spring it is a thin layer, in the autumn this same layer is divided into alburnum, liber, and the remains of itself. It is, moreover, subdivisible into separate small parts longitudinally, each of which contains the specific essentials of the whole, namely, the formation of bark and wood, and the rudiments of roots and shoots. This last assertion is verified by what is often seen on the surface of the alburnum of a decorticated tree. The surface of the alburnum is unequal ; it is varied by little furrows or crevices, and which, when the bark is stripped off, retain, in some instances, small portions of the envelope. These insulated portions, however, soon show their vital property by swelling from their stations, and by spreading themselves over the naked wood, assist materially to close the wound. The foregoing observations are intended to support the idea, not only of the identity of the vital envelope as a distinct member of the system, but also its com- pound character as containing the rudiments of both roots and buds ; and, moreover, the source of all accretion, whether as to the magnitude or number of the parts produced. That a finite quantity or number can be infinitely divided has always been a mystery, except only to SEAT OF VEGETABLE LIFE. 139 the geometrician or mathematician ; and to suppose that a like property is possessed by any member of a plant is equally mysterious. Yet something of the kind must be admitted before we can rationally account for the interminable reproduction of peren- nial plants, or of the endless division of parts of plants. The foregoing idea of the existence of a distinct vital member, whence all new accretions proceed, is directly opposed to the modern doctrine of the " organisable property " of the elaborated sap of plants. The idea is founded upon the general law of vegetable nature ; for where do we find the most insignificant vegetable body come into visible exist- ence without having a pre-existing embryo or rudi- mental atom, whence it derives its essential structure and qualities. There is no such instance in nature. Can the most minute species of Fungi spring forth without its propago, or the smallest herb without a seed, or previously existing part of itself? Is the bark or wood self-productive ? No : when either is destroyed it cannot be renewed but by the assistance of that vital member which is the origin of both. Admitting, then, that plants and certain parts of plants possess the property of perpetual reproduction and extension, a question follows : How is this sub- division effected ? In the case of bulbs it has already been stated, that the radicle plate is composed of an endless train of gems, which are developed in the order of their seniority ; tubers are multiplied by 140 SEAT OF VEGETABLE LIFE. division or branches ; fibrous-rooted herbaceous plants perpetuate themselves by lateral offsets ; but how is the annual subdivision of the vital envelope of trees accomplished ? To this question a direct answer cannot be given, because the process is invisible ; but we can gain a knowledge of the changes which take place between the wood and the liber of a tree by making frequent incisions through the bark, and marking the changes during the spring, summer, and autumn growth. In early spring, say in the beginning of February, the transverse and vertical sections of the stem of four years old appears as represented. (Fig. 43.) Fig. 43. Transverse and perpendicular sections of a stem four years old ; the latter through the pith, a, pith and wood of the first year ; 6, c, d, layers of wood of the second, third, and fourth years ; e, the four thin layers of hark. About the end of May, sooner or later, according to the favourableness of the season, similar sections of a stem of the same age will appear as Fig. 44, SEAT OF VEGETABLE LIFE. Fig. 44. 141 ^^"S^^a^ 6 Sections of a stein as it appears in May or June of the fifth year. he white spaces show the swelling cambium. A t". t.nP PTln nf SQTkf OYYll^Y 0-->/1 !*- -->nr\-ir 17-T-M/lrt f*f The white spai At the end of September, and in many kinds of trees much sooner, the sections appear as in Fig. 45. Fig. 45. Sections of a stem at the end of the fifth year. The envelope and layers of liber are too thin to be shown by the pencil. Here we observe that a new concentric layer of alburnum has been added during the fifth summer, and also an additional layer of liber has been parted off, and placed close to that of the preceding year, and lined on the inner side with an almost imper- ceptible membrane or coating of gelatinous matter, which is the vital envelope, and from which the new growths of wood and liber of the next, and all suc- ceeding years will be produced. 142 SEAT OF VEGETABLE LIFE. Judging, then, from these changes, about which there can be no doubt (because of them we have ocular proof), we may conceive that the vital envelope is constructed of an indefinite number of distinct con- centric layers, two of which are developed annually ; the inner one (A, Fig. 46) being inflated into alburnum, and the outer one (B, Fig, 46) into a layer of liber. Segment of a transverse section of a tree five years old, magnified : a, growth of alburnum first year ; 6, the second ; c, the third ; d, the fourth ; e, the fifth ; /, five layers of liber, ideally mag- nified ; #, epidermis and cuticle. The appearance of the structure of the alburnum affords confirmation of the reasonableness of this idea. If we examine it as soon as it is formed, or in any future stage of its existence, we find the longitudinal fibres strongly and distinctly marked,* and the minute vesicles of the cellular fabric between the fibres posited horizontally ; showing that they are enlarged in the same direction that is, advanced from the centre of the tree outwards. (Fig. 2.) This hypothesis is only objectionable, perhaps, on the ground of the difficulty of conceiving how such a mass of organisation, forming the extended trunk of a full grown tree, can be contained in such a slender space as that between the liber and SEAT OF VEGETABLE LIFE. 143 the wood of one of four years' growth. But this difficulty is not greater, indeed not quite so incom- prehensible, as is the other supposition already alluded to, namely, that all increments are elaborated from juices and qualities inherent in the plant ; or formed by accidental associations of certain electro-chemical bodies extractable from the earth, air, and water. The identity of the vital envelope, during summer is visible and palpable ; and if in winter it be only a cincture of transparent cellular matter, no doubt need be entertained of its subsequent expansibility. That vegetable matter appears in the first stage of its exist- ence as a colourless homogeneous mass is indisputable; and that it gradually gains consistency and organic form, may be easily believed by examining an orange when first visible in the flower, and again when fully ripe and deprived of its juice. Besides, the accrescent powers and indefinite limits of vegetation in this case, should banish incredulity ; in many other instances it is equally surprising ; witness the monstrous gourd, the majestic oak, the magnificent Banyan Fig; the latter shading acres of surface, all originating in an atom of a seed. The new layer of wood which is added on the old stem or trunk, ranges with the first layer of wood on the terminal shoots. On the latter all primary buds, and consequently branches, originate. The shoots developed this year, except water shoots*, are based * Water shoots are such as are produced on luxuriant growing shoots of the present year, frequently seen on the peach, apricot, and always on the grape vine. 144 ORIGIN OF BUDS. on the alburnum formed on the last ; and the buds formed in this year are seated on this year's alburnum, and on which they remain to be developed in the next or some following year. The pith, wood, buds, and bark of every shoot are all simultaneously produced. But all buds or branches are not primary. Such as are produced from an old stem (b, Fig-. 47) whether . Fig. 47. Example of a primary shoot a, and a secondary shoot b. The former is seated on the alburnum of the first year, the latter on that of the third. naturally, or by consequence of pruning-, may be called, for the sake of distinction, secondary*. These can have no immediate connection with the first formed layer of wood and pith, and therefore invari- ably spring- from the envelope. The following deli- neation represents the disposition of the layers of wood and bark, with the places of the primary and secondary buds or shoots, on a section of an abbrevi- ated stem of a tree of three years' growth. * Botanists suppose that there are what they call " adventitious buds," that is, if buds come forth from other places than the axils of the leaves or bractea, they are adventitious and new creations. Their appearance, indeed, may be adventitious, but not their identity. If a bud can be produced without a rudiment, so may a whole plant. ORIGIN OF BUDS. Fig. 47, 145 d 1830. 1829. 1831, 1830, 182Q. 146 ORIGIN OF BUDS. This figure shows, that the lateral shoots, d, c?, (/, d> and new layer of wood, b, b, on the lower part of the stem of the present year, are not attached to each other ; and that the growth of the former can only affect that of the latter indirectly ; nor can they (the shoots, d, d) d, d, except the leading one, c,) be sup- posed to assist the formation of the new zone of wood by ejecting fibres down into it ; because their fibrous attachment is upon the alburnum, as at e, e, Fig. 47 ; that is, upon that division of the envelope which was formed into alburnum in the previous year. The young shoots which are elongated and bear the foliage of deciduous trees, are pretty regularly studded with buds along their whole length, though only a small number of them are developed in sue- ceeding years. A few at the point always burst, namely, the leader and two or three laterals, part of the latter being resolved into branches. Some of the lower situated are prolonged into spurs, and become flower buds, as at^J g, Fig. 47 ; many remain dormant, and are never developed unless the stem be cut over immediately above their station. From these circumstances it appears, in respect of secondary or tertiary buds springing fr*om the vital envelope, that that member is possessed of these latent principles, which are put forth when surrounding circumstances favour their develop- ment. It was this fact which induced an emi- nent French botanist to imagine, hat vital gems ORIGIN OF BUDS. 147 floated in the sap : for on no other principle could he account for their inexplicable appearance. There are many trees having- a fine smooth trunk from which not a spray would be put forth while its branched head remained alive : but on being- decapi- tated thousands of shoots would issue from the bole, even if its pith, and almost all its body of timber had g-one to decay ; a strong proof that the envelope contains the rudiments or principles capable of being resolved into buds as well as of radicle fibres. It has been supposed by some physiologists, that the medullary rays are the tracts of buds, and that all buds originate on, or proceed from the pith ; but we have no certain evidence of the truth of these ideas ; on the contrary we find, that buds of many kinds of trees issue from roots where pith has never existed; and medullary rays, or partitions rather, are abundant where no buds are ever or can possibly be produced, viz. on the internodes of jointed stems ; example, the grape vine. And it may be further observed, that in the plant just named the greatest number of shoots, in fact every shoot, is ejected from the articulations where the pith is visibly interrupted. Of what are called medullary rays, we may observe further, that though known by this name, they do not all take their rise from the pith ; as the stem increases in diameter, intermediate par- titions come into existence at different distances from the centre, and appear to originate in the bark rather than in the pith. L 2 148 ORGANISATION AND This view of the constitution of a tree shows us that it is not, as usually considered, an individual being-. It has, indeed, a congeries of roots, a pith, a principal stem, and a general covering- of bark, in common; serving the purposes of sustentation, sup- port, and protection to the whole ; but it has not only one it is composed of many principles of life dispersed over its whole surface. A tree is a vege- table polypus ; capable of unlimited division and sub- division of its parts, without injury to, and without any notable diminution of the original. Not only is every seed, but every bud a perfect being, endowed with a living reproductive principle in itself; and whilst a tree is considered as a vast assemblage of vital entities, requires to be treated as if only an individual. As some of the foregoing ideas are new, and at variance with generally received opinions on the subject, the writer only craves a patient examination of his statements. He appeals to nature ; and trusts that the impartial and unprejudiced inquirer after truth, by comparing the phenomena themselves with what has been advanced concerning them, the con- clusions on both sides will not greatly differ. In the preceding part of this section we have asserted, that all new accretions spring from a pre- viously organised body ; whether that be a propago or see'd which is deciduous, or from any part of a plant, as a bud, graft, layer, or cutting (that contains a part of the vital membrane and incipient buds,) APPENDAGES OF THE STEM. 149 separated by art. This idea is however controverted, it being- held by many eminent physiologists, that the new accretions are formed out of the elaborated sap ; and particularly the new layer of alburnum, which is every year added to the axis of the stem. In whichever light we view the different appear- ance, state, or qualities of the sap of trees, &c., whether as gum, resin, jelly, or water, it is perfectly homogeneous ; and whether contained in the body of the plant yielding it, or in the gallipots of the druggist, it is always found free from any fibrous or other matter that could possibly by combination form the organic structure of a plant. We are, therefore, we may again repeat, confirmed in opinion, that woody structure and substance can no more start into exist- ence without a rudimental basis, than that an entire tree can be produced without either seed, cutting, or layer. Vegetable growth is only distension, expansion, or amplification of a rudimental membrane : and the elements composing this membrane are increased by the assimilating power of the organic apparatus of the plant. Appendages of the stem. These are hybernacula or bud covers, leaves, stipula, spines, prickles, ten- drils, glands, awns, hair, downs, bractea, natural exu- dations of the juices, and floral members. Hybernacula. As seeds have various coverings, so buds, whether of leaves or flowers of shrubs and trees, are protected during hybernation, or before expansion, by an envelope of membranaceous leafits 150 APPENDAGES OF THE STEM. which are usually deciduous singly, or thrown off together like a cap. They are seated at the base of the bud, over which they are arranged like scales. In some plants the hybernacula are covered with down : others with a thick adhesive gum, which is an additional security against frost. The sheaths of the Graminece and of bulbous and tuberous stemmed plants, are only modifications of this temporary defence. This appendage is particularly imposing in Crocus ; and on extra-tropical trees, every bud, whether promi- nent or incipient, is furnished with this kind of protec- tion. Leaves. The leaves are the most striking appen- dages of plants. As they are beautifully organised they must answer some important purpose in vege- table economy. They have been called the lungs of the plant, no insignificant term ; and as they aggre- gately present an extensive surface to all atmospheric influences, they must be, from this very circumstance, considered as indispensable members of the system. That extended surface and foliaceous structure are necessary to vegetative development in general, may be inferred from the fact that the stems of many of what are called succulent plants, and which have few r or no real leaves, are flattened so as to present as large a superficial plane to the air and light as possible. Leaves are inspiratory as well as perspiratory organs. Gaseous qualities are probably emitted as well as inhaled by them ; and that they both absorb and perspire away aqueous matter is well known. APPENDAGES OF THE STEM. 151 Such functions are mainly instrumental in producing a constant flow of sap upwards. In proportion to the expanse, or quantity of foliage, in like proportion is the need and consumption of water. Indeed their hydraulic agency seems to be their chief office ; the amplification of the plant could not take place with- out such agency to assist the intestine impulse of the swelling vessels. It has been observed that shoots having leaves upon them, cut oif from the tree, quickly wither ; but, if the leaves are taken oif, the shoots will remain plump a much longer time ; a proof of their transpiring powers. Although the leaves are attached to the bark before as well as after their expansion, the connexion is only temporary. Those of deciduous trees drop or wither as soon as the summer growth is over. Some shrubs and trees shed them in the second or third year, hence they are called evergreens ; and the fir tribes retain their foliage for many years. In the latter case it seems their persistency is only owing to the resinous consistency of the sap and suberous charac- ter of the bark, or rather that they are not all appended to buds as are those of other trees. In all cases the attachment is not very intimate; there being no connecting fibres or other vessels of a per- manent character passing from one to the other ; all such being articulated at the junction, except only the palms, in the early stage of their growth, and all other plants having what are called " spurious stems," viz. stems chiefly formed of the permanent bases of 152 APPENDAGES OF THE STEM. the petioles. The sap vessels of the bark are con- tinued into the leaves ; but their office as ducts ceases with the fall of the latter. In structure leaves are furnished with a beautifully branched petiole, curiously divided and articulated like arteries and veins, or ranged in nearly parallel lines ; the interstices being- filled up with a pulpy, paren- chymous, green substance, covered on both sides by a cuticle, which is said to be porous to allow the transmission of fluids. That the superior and inferior surfaces have different functions, or are differently acted on by the air and light, is manifest from the circumstance, that if their natural position be reversed by force, they will very soon regain it if at liberty. There is a remarkable exception to this, however, exemplified in the genus Alstrcemcria, the leaves of which having tortuous petioles present their inferior disc to the sky. Leaves differ much in substantiality ; some are thin and transparent, others thick and fleshy. Those of some of the Aloes and Crassulacea, as has been before observed, cannot with propriety be called leaves, because, if slipped off and placed in a favour- able situation, they become perfect plants ; thus ex- hibiting a property of a stem rather than of simple leaves. Such appendages are in fact foliaceous stems. There are several plants wiiose leaves, if planted in moist heat, will exsert root fibres, and keep the leaves alive for a considerable time ; but being destitute of the organisation of a stem, never can produce any APPENDAGES OF THE STEM. 153 additional member of a plant. Leaves there are, however, which have a peculiar organisation, as those of Phyllanthus and Brybphyllum, (Figs. 48 and 49,) Fig. 48. Leaf of a Phyllanthus^ showing the flowers borne on the edges. Fig. 49. Leaf of a Bryophyllum, bearing viviparous progeny. the branched petioles of which are the peduncles of the flowers, or the runners for bearing the viviparous progeny of the plant. There are other bracteous leaves similarly organised, as Echeveria livida, which, if only laid on moist soil, readily strike root, and produce new plants. The leaves of Gloxinia produce young plants. A callosity is first formed from 154 APPENDAGES OF THE STEM. the bottom or broken part of the midrib ; this in- creases to a kind of tuber which, after a time, ejects both radicles and stems, a clear proof that detach- ments of the vital membrane are projected into the leaves. Leaves are, except in some of the Coniferce, always closely connected with the buds : indeed, it- seems the former are only detachments of the bark to permit the escape of the latter. They generally accompany each other ; and in some kinds of trees the buds are formed within the base of the petiole. Amplitude and deep colour of the foliage are sure signs of high health and vigour, as a pale colour and diminutive size of leaves are indications of weakness or disease. So the rugose texture of their surface is a mark of barren luxuriance, whilst com- pactness and polished appearance of the disc, indi- cate not only perfect health, but fruitfulness also. This is strikingly visible on the grape-vine, melon, and strawberry : the reason is, perhaps, that the swelling fruit requiring a large share of the rising sap, checks the expansion of the leaves, and ren- ders them firmer in texture and less in size. From the state or changes of the leaves it is quite evident, that though the root be the chief organ for supplying the nutriment of the plant, the leaves are certainly the exciters of what may be called the appetite. They are constantly, especially under the action of a cloudless sun, craving supplies. Their surfaces all turned sunward, receive both light and APPENDAGES OF THE STEM. 155 heat, whence they derive colour, and their juices motion ; the latter become subtilised and evapo- rable, and as, they fly off, leave them insatiate for fresh supplies. This agency of the foliage, there- fore, gives an impetus to every current in the system, and consequently must have a powerful effect in advancing the amplification of the plant. To the agency of the leaves have been ascribed the fruitfulness of trees, and the more perfect matu- ration of the tubers of herbaceous plants. Both bulbs and tubers, it is said, being more or less enlarged according as the leaves are able to " throw down " ample supplies of elaborated sap. Now, although it be unquestionable that the leaves are recipients of divers atmospheric principles and influences neces- sary to the plant, and their amplitude and vigour are proof of their powers for that purpose ; yet we find on examination, that the rule js not universally true, that bulbs and tubers are large in proportion to their system of foliage. We may only instance the most leafy individuals in a field of turnips, carrots, parsneps, &c., which are always found to have com- paratively smaller tubers than the less leafy portion of the crop. We may also remark the disparity of the tubers and foliage of the short-top radish, as further proof that tubers are not always in size pro- portioned to their quantity of leaves. Moreover, we may repeat, that both bulbs and tubers are occa- sionally produced without the assistance of leaves. Stipulce. This name is given by botanists to a 156 APPENDAGES OF THE STEM. minor order of foliage usually seated at the base of the proper leaves, in the near neighbourhood of the buds, to which, perhaps, they are in some way neces- sary. Their special use in the system is not, how- ever, very apparent, though from their station they may be necessary in some way or other to the matu- ration of the buds. Spines, Prickles, Stings. These are called the armature of plants. Spines originate in the wood, as Pyrus, and seem to be abortive shoots. In Ulex they are the extremities of the branches, and retain their vitality for years. Prickles are produced on the bark, or on the leaves, and have only a tem- porary existence. Both these appendages are osten- sibly for defence against browsing animals ; more especially of those kinds of plants that are armed when young, but lose their armature when grown up and out of the reach of cattle : example, the white- thorn. Some trees appear to be particularly guarded against climbing animals, as Gledltschia horrida. Many plants, as Mammallaria, are leafless, but pro- fusely covered with spines ; these, probably, do the office of leaves ; but other functions are attributed to them, namely, that they are conductors of electric 'currents supposed to be especially necessary to these plants. Stings, awns, hair, down, on the surface of plants, are all appendages of the same nature, and all necessary one way or other in the economy of the vegetable. The hairs on some twining stems are reflexed. APPENDAGES OF THE STEM. 157 Tendrils. Are tortuous processes produced by- weak stemmed plants to enable them to cling to, and support themselves on other plants or bodies in the air. Some are produced from the wood, and are permanent, though they lose vitality in the second year, as the grape vine. In this last-named tree, the first two, three, or four tendrils at the bottom of the shoots, are the common peduncles of the thyrse of flowers if they receive the requisite supplies of air, light, and heat ; but if these elements be wanting, the flowers are imperfect and abortive : of course the peduncle is resolved into a barren tendril. Every plant that is furnished with such members shows its climbing character, and that it is not intended by nature to grovel on the ground. Some climbers support themselves by the reflexed position, or twisting character of their petioles, and others by the paw- like form and insinuating processes of their clinging fibres* Spiral tendrils convolve first one way for about half their length, and afterwards the contrary way. Glands. Are small protuberances seated on va- rious parts of plants. They appear to be either secretory or excretory organs. Root fibres are observed to proceed from them in the case of layers* Those on the petioles are particularly conspicuous, and from their form only, it has been conceived they indicate a peculiar character of hardihood, or a cer- tain susceptibility of the plant to suffer under, or resist, certain influences of the atmosphere. On the 158 APPENDAGES OF THE STEM. young* luxuriant shoots of the vine, small transparent bodies like vesicles decorate the stem, petioles", and tendrils. They are slightly attached to the cuticle ; but what their use may be in vegetable economy is not apparent. They are, however, evidently of a glandular character, and of the same nature as the icicle garniture of Mesembryanthemum cry stall* - num, and of what is called bloom on many kinds of plants. Exudations. Besides the accidental flow of sap from wounds, there are several instances of natural discharges which may be noticed. The buds of most of the Pinus genus are covered, during winter, by a coat of pure resin, which is exuded from the hyber- nacula. Those of the Pbpulus balsamifera are shielded by a fragrant gum. Honey-dew has been considered as a discharge from the leaves and stem ; but as this is never seen unaccompanied by the Aphides, it is probably emitted by those insects. The fluid oozing from the naked stigma is no less remark- able than is the real honey secreted in the bottom of the corolla. Both are elaborated and secreted by the flower, and, as well as being necessary as food for numerous insects, furnish for the use of man one of the purest and most luscious of vegetable extracts. A curious distillation of water is preserved by the Limnocliaris Plumieri, which, from a tube occupy- ing the middle rib of each leaf, discharges pure water in frequent drops from an orifice at the apex. Being an aquatic, it would appear that the plant is APPENDAGES OF THE STEM. 159 furnished with these pipes to carry off any excess of water received into the system. Bractea. This is a foliar expansion, occupying a middle station and character between the proper leaves, and the Horal members of the plant. Though most commonly seated below the florets, as in Jus- ticia, it is above them in Eucomis. In some instances it resembles the proper leaves, as in Mcspilus ; but is often of a membranous texture, as ffellebbrus. In some cases it is not easy to distinguish bractea from involucre, or even from the calyx. The spatha, per- haps, is only a modification of bractea borne by lilia- ceous plants. Were it necessary to proceed with each succeed- ing member of the inflorescence, we should have to notice in the order of their development, the calyx, corolla, nectarium, stamina, pistillum, pericarpium, or fruit ; but these are all so well known and so mi- nutely described in every botanical work, that the task would be superfluous, especially as it would elicit nothing new, or at least nothing but what has been already mentioned, or what will require to be repeated when we come to treat of the expedients necessary to be attended to, or practised, in cultivation. We have alluded to the functions of the different members of plants, as we have had occasion to mention them ; but we pretend not to know the uses of all. In con- sidering the floral members, we see the use of the bracte, and also that of the calyx ; both being evidently defences to the sexual organs ; and these last, from 160 APPENDAGES OF THE STEM. their station and peculiar functions, declare at once their respective offices. But what can we say of the corolla and nectarium, those splendid appendages and chief ornaments of plants ? Do they administer to the perfection of the interior parts? They can hardly be deemed defences, more especially as they are not only unfitted for such office, by reason of their extreme delicacy, but also because, in most cases, they turn away from the only position in which they might #ct as a guard to the interior parts. Here we can only pause and admire ! But notwithstanding our ignorance in this case, we may rest assured, that these beautiful appendages are not superfluous, but answer some useful purpose to the plant itself, or to some other link in the chain of being. Do their colours indicate their specific qualities for the use of man ? Are their brilliant hues intended to lure insects, in order that they may not only find food, but also assist nature in the distribution of pollen* ? Or are high colours given to plants as a decoration only ? Such questions have not yet been satisfac- torily answered, though we may safely conclude, that both the distinguishing characteristics of colour and scent are produced by the qualities of the plant, not- withstanding the immediate causes of the various * There are some sorts of improved fruits, which, if their seed be sowed, rarely produce progeny exactly like the parent, or like each other. Is not this owing to the flowers being so constantly visited l>y numerous tribes of bees ? Ex. the gooseberry. APPENDAGES OF THE STEM. 161 tints in the same flower, and specific scent of all flowers is beyond our comprehension. But as a general remark we may add here, that when we con - template all these various members of a plant, whe- ther with regard to their structure or functions, we see much to fix our attention ; the diversity of forms and of texture the extreme delicacy and vivid colour of the flower the rich pulp of the fruit and curious conformation of the seed-vessels are all admirable ! and when we consider further, that all these forms, whether ligneous or succulent, are composed of simple cellular matter, we are astonished ; that the same element should be so differently arranged that such different qualities should be concocted such odours effused, and such colours reflected from the same material ! 162 CAUSES OF THE BARRENNESS OF TREES EXPLAINED. HAVING noticed the ^different members of trees in the order of their development, we now proceed to another branch of the subject, in order to advert to some circumstances of the growth which are involved in considerable obscurity. In the foregoing remarks on vegetable structure it has been assumed, that every part of a plant has spe- cific form and existence before expansion. That there is no such thing as accretion by addition of new organs, but simply by extension and amplification of those already in existence. But as there are several circumstances which appear to militate strongly against this idea, it is necessary some explanation should be given. The opposing circumstances are the following, viz. If all trees of the same age and kind are formed alike, and every one composed of every member or part that ever will or possibly can be produced, how does it happen, that one shall be fruitful and another barren ? Why does a fine, healthy, free-growing tree show CAUSES OF BARRENNESS, &C. 163 no flowers, and consequently yield no fruit, while a stunted, or even a sickly one, yield both abundantly ? How is it that a tree, a grape vine for instance, in full vigour as to age, and previous fruitfulness, shall suddenly become barren if removed from a higher to a lower place in the vinery, though at the same time its growth be accelerated ? Why are healthy shoots from the stem, or from the crowded interior of a tree, always sterile, whilst those of the exterior are prolific ? Before these questions can be answered, or the answers understood, it will be necessary to consider first the real nature of the connection between those members which constitute the bulk of the plant and the fructiferous gems contained therein. The former are the annually increasing bodies of bark and wood ; these are enlarged to a greater or lesser size, and in a longer or shorter time by the favouring circumstances of soil, situation, and season. The incipient fruit- bearing gems are seated on the pith at the base of every bud, whether lateral or terminal, of our common fruit-trees ; but their development does not depend on those circumstances which prompt and assist the growth of the wood and bark, but on a stationary re- pose in which their organisation is engrossed, matured, and fitted for perfect and vigorous expansion, by the influences of full air and light. The maturation and development of the fructification are subdued by the exuberant growth of the other constituents, whereby that rest, or stationary existence is denied, and there- M '2 164 CAUSES OF BARRENNESS, &C. fore the gems are either carried along another stage in the growth of the shoot or spur containing them, or remain inert in the body of the stem for ever. But why, it may he asked, if the fructification be centrally posited as in the bud g, Fig. 47, and ulti- mately displayed on the summit of a similar one on a spur as &tf) Fig. 47, how is it not protruded, as it is natural to suppose it would be, at the first movement of the bursting bud ? To this it may be replied, be- cause the incipient flower is then imperfect, i. e. im- perfect as to bulk, not as to form, and because, at the same time, such is the excitement of the growing principle, that the bases of the buds A, A, Fig. 47, en- veloping the fructification, are elongated forth, carry- ing the gem forward therewith in their apices. We are now alluding to leading shoots, which are seldom fruit-bearers ; but that fructiferous gems are present in the points of even strong leading shoots, we have only to recollect how often we have seen terminal flower buds formed in the autumn on both apple and pear trees as at c, Fig. 47. It appears, therefore, that though the fructiferous gems are in- cipiently present in all cases, it is absolutely necessary to their perfect maturation in the bud, that moderate growth of the tree to allow time for this, and full supplies of air and light are requisite to bring them to perfection. There can be no doubt but that the flower bud c, Fig. 47, was at the base of the shoot, or in the bud whence it sprung, before its elongation in the previous spring ; CAUSES OF BARRENNESS, &C. 165 and that the flower bud^J was only a leaf bud twelve months before. But here it may be asked how does this terminal bud c, Fig. 47, gain maturity without that stationary repose which is affirmed to be neces- sary in other cases? Because such shoots bearing- flower buds cease to grow at an early period in the summer, as every one acquainted with fruit-trees must have observed, and this topmost bud, from its central station, thereby receiving extraordinary excitement, is forced into perfect form in advance of those which are laterally situated on the same shoot. But the fructiferous organs are not always terminal. In many plants they are projected laterally, and are perfected in the first, second, or third year, according as circumstances are more or less favourable. The peach and Morello cherry are perfect in the second year ; those of the May-duke cherry, naturally, not till the third ; but as a proof that flowers are present in the lateral buds, even in the first, we may instance the practice of Mr. Fintelmann, royal gardener at Berlin. This respectable practitioner finds that if he stops the strongest shoots (of his potted May-duke cherries intended for forcing) in the month of June, or some time before the summer growth is over, and divests the lower part of the shoot of two-thirds of its buds, those that are left will put forth flowers and bear fruit the following spring. Thus, then, it appears, that, though the fructi- ferous organs are incipiently present in all cases, they either require a certain maturation (technically, 166 CAUSES OF BARRENNESS, &C. ripening- of the wood) in a stationary state, or some preternatural excitement before they can be perfectly developed. Thus it is why luxuriant growing trees are barren ; and this is the cause why a tree deprived of full air and light yields no fruit ; and also the cause why a branch of a fruitful vine, if lowered from its station near the glass down on a trellis near the floor, will grow luxuriantly, but instead of perfect branches yields only naked tendrils. The fact, that over free growth retards the produc- tion of flowers and fruit is evident from many cir- cumstances occurring in vegetation. Seeds, from long keeping, or from being immoderately dried, always rise with less vigour, and present the fructifi- cation sooner than such as are fresh and plump. The reason is because the cotyledons are deprived of a part of their juice, which is destined to invigorate the infant plant ; consequently, when sowed, they vegetate slowly and imperfectly ; but the corculum, from its central position, being less debilitated than its investments, progresses before these, and the result is earlier flowering and maturity of fruit. If bulbs be exposed to unnatural desiccation, the outer investment becomes parched and stationary ; but from the central store of sap and vitality the flower issues forth before the leaves. Or, in the case of a bulb being injured by frost, the leaves only are paralysed, and the flower stem is protruded alone. That the fructification exists, and has form as soon as the other parts of the plant, is manifest from CAUSES OF BARRENNESS, &C. 167 the history of the Andna. T. A. Knight, Esq., in one of his papers presented to the Horticultural Society, asserts, that the effects of very dry or very cold air will " cause even the scions from their roots to rise from the soil with an embryo pine apple upon the head of each, and every plant to show fruit in a very short time, whatever were its state or age." Now this shows decidedly that the whole organisa- tion of the plant is complete from the first, and, by checking the growth of the exterior, the central part, hearing the fruit, comes forth prematurely ; but which could not be the case did the formation of the fruit depend entirely on the quantity of sap " thrown down " by the leaves. Annual plants run to seed sooner or later accord- ing as the soil they grow in is rich or poor. On a dry gravelly soil plants are diminutive and preco- cious ; on rich fertile land they are exuberant and late : because the growth of the stem and leaves, deriving a full supply of nutriment, are enlarged to their utmost volume, and of course delay the develop- ment of the flowers and seed. Here it may be added, that the difference in the magnitude of plants of the same kind is not so much caused by a diminution of the number of their parts, but by the diminished bulk of each of them. From the whole of the foregoing observations it is sufficiently manifest that every different part of a plant has original existence. From the moment it begins its career of growth all its parts are in a course 168 CAUSES OF BARRENNESS, &C. of gradual development ; sometimes, in the case of trees, the two principles of growth and fruitfulness progress together, equally balancing each other ; at other times controlling or neutralising each other; abundant fertility checking the growth, and exuberant growth preventing fruitfulness. Here it is necessary to observe, that trees may be barren from other causes than over-luxuriant growth. The fructiferous gems or principles may be present though abortive ; trees may be covered with flowers, and yet produce no fruit. This arises either from constitutional weakness, the depredations of insects, or ungenial weather. A vine may show its incipient bunches at every bud that bursts ; but if there be a want of air, or light, or heat, or of sufficient energy in the tree, no flowers will be expanded, nor fruit perfected ; the bunches will be resolved into tendrils. When the growth of a tree is moderate, and when flower buds are exhibited over all the spray, not only are the flowers of this year strongly formed and expanded, but those of the next are ready to start forth; and, it not unfrequently happens, do come forth late in the summer or autumn, especially if the first flowers have been cut off by frost, insects, or other accident. It is in such cases we sometimes witness a struggle between the growing and fruc- tiferous principles; some of the second flowers become monstrous; the axis of the shoot being prolonged through and beyond the imperfect flower, leaving a portion of the pulpy part of the pericarpium on the CAUSES OF BARRENNESS, &C. 169 shoot, at the point where a perfect fruit, in other circumstances, would have been formed. Notwithstanding this irregularity, and intermix- ture of distinct organs in the growth, (which may be easily traced to be effects of accident, or extreme cul- tivation,) it has furnished some physiologists with an idea that such exhibitions indicate the true reason why one tree is prolific and another barren : why one tree shall every year be covered with blossoms, and another of the same kind present nothing but leaves. The sexual organs of plants they assume have no positive identity ; but are only modifications of the previously existing members which compose the stem, and which are resolvable, either into leaf or flower-buds, as circumstances govern. That there is some corresponding analogy between the members of a stem and those of a flower, may be admitted. We have only to refer to the doctrine of the old botanists for confirmation. They declared that the calyx was the termination of the outer bark the corolla, that of the liber the stamens rose from the wood and the pistillum, &c., from the pith. These old ideas have, however, become obso- lete ; and instead of them we are now taught, that " the pistillum is either the modification of a single leaf, or of one or more whorls of modified leaves," and " that in the course of the advance of it to ma- turity, many alterations take place in consequence of abortion, non-development, obliteration, and union of parts." De Cand. 170 CAUSES OF BARRENNESS, &C. This doctrine being espoused by some of the most distinguished botanists of the age, it is painful to be compelled to doubt the accuracy of such authorities. Perhaps it is necessary to dip deeply into the abstract science of physiology, before we can comprehend the arcana of vegetable transformations. Mere practical discernment cannot exercise such powers of imagina- tion as to conceive, that by checking the free growth of a tree, it will induce an accumulation of matured sap, which shall operate so as to stunt the points of the branches into flowers turn the most simple appendages of the exterior into the interior and transform these inferior organs into the principal and most important of the system. Can any practical man imagine, that by checking the growth by trans- plantation cutting the roots ringing or disbarking a tree, that such violence will gain a greater share of matured sap? impossible. On the contrary, he knows the effects will be injurious to the whole system ; and though the fructiferous principles will be called into action as the final effort of a sickly tree, this result is not from an accumulation of sap, but the very reverse. Surely accidental metamor- phoses may be acknowledged as such without over- turning the natural order of vegetable develop- ment. Whether the old or the new ideas on this impor- tant point of vegetable physiology, be the more cor- rect, or whether the one or the other be faithful descriptions of the origin and conformation of flowers, CAUSES OF BARRENNESS, &C. 171 we shall not presume to decide ; but venture to assert that if the modern notion be true, it detracts from the ideas generally entertained of the simplicity and beautiful arrangements of vegetable structure and evolution, and which we naturally deem to be results of fixed laws : whereas, it seems that such essential forms are only the effects of adventitious associa- tions ! If, however, proofs of these fortuitous conforma- tions were afforded by plants in a state of uncultivated nature, some credence might be bestowed ; but when they are only drawn from pampered varieties, the monstrous children of art 9 in the shape of roses, Crasanne, or Colmar pears, highly cultivated plants, we deem the examples unsatisfactory, and inferences from them erroneous. Irregularities, malformations, abortions, and mon- strosities, are frequent among highly cultivated plants. The chief favourites in the flower and kitchen gardens are examples ; but they are all casual, and confessedly spurious productions : being exceptions to the fixed laws of vegetable development, and in no case to be taken as a rule in describing it. Irregularities in development are also seen independent of any inter- ference of art. The round and imbricated galls on the oak, and the mossy tufts on the shoots of the sweet- briar, are the niduses of insects. But these, like the manipulations of man, only cause aberrations in dis- position, and multiplication of parts, without being considered as constitutional characteristics. We 172 CAUSES OF BARRENNESS, &C. sometimes see the mutilated scape of a narcissus resolve itself into and do the office of a leaf, but it would be truly wonderful to see a leaf, or any number of leaves, resolve themselves into a flower ! We also witness the mutability of monoecious and dioecious flowers ; showing that such plants are constitution- ally provided with the principles of both male and female flowers on other parts of the plant than where they usually appear : and that soil, situation, or season sometimes operate to produce either or both, as circumstances determine. Even the mutilated stem of the common white lily will pro- duce bulbs at the fracture, when the development of the flower is prevented. But to maintain that the flowers have no positive identity in the constitution of the plant, or, what is nearly the same thing, formed of the proper leaves, is and must be as perplexing to the botanical student as it is to the practical man. The latter is well acquainted with the transformations visible among highly cultivated plants. He ascribes them to accident, and to the changeability of the vegetable fabric under the expedients of cultivation. And though he may wish to believe, that by possi- bility a flower is but a stunted branch, for the sake of agreeing with his superiors in science ; yet he finds much difficulty in applying the doctrine gene- rally. Among pomaceous plants, a distant resem- blance may be, by the help of imagination, traced ; but how can he apply the doctrine to such plants as the tulip? in this case he must call the flower an CAUSES OF BARRENNESS, &C. 173 expanded offset : in Stapelia and Cereus, where there are no foliar expansions, the flowers must be considered as distorted stems : in Mammalaria, metamorphosed mammce, and the flowers of such plants as the strawberry, must be accounted flori- ferous runners. If flowers of trees be stunted branches then perfect branches are runaway flowers; and if sepals, petals, filaments, and pericarps be only modified, contorted, and discoloured leaves, then are perfect leaves only vagrant bracti, sepals, &c. c. Much satisfaction and amusement, no doubt, arises from the study of the more occult processes of vege- table transformations ; and there is much merit even in the attempt to give a rational account of them ; but much care is necessary to distinguish perfect from imperfect, regular from irregular development. When perfect, the arrangement of structure, the form and functions of the several organs, and all the exhibited phenomena of growth, are similar in every plant of the same family ; but occasionally indivi- duals differ, and fly away from the regular order of development. Some accident of treatment, perhaps, or peculiar circumstance arising from soil, situation, or season, will cause derangement of structure by reduplication of members, as in double flowers, or by partial destruction or mutilation of organs. Some genera have constitutional powers of metamorphoses, yielding plants, instead of seed, as Lilium ; com- pressed, instead of quadrangular or cylindrical stems, as Asparagus, Epiphyllum, &c. These last are 174 CAUSES OF BARRENNESS, &C. constitutional deviations; the former are only, as be- fore observed, accidental exceptions. In fine, science has proved, and experience confirms the fact, that the floral members are resolvable into leaves ; but the difficulty with the practical man is, whether leaves be resolvable into flowers and fruit. That curious and at the same time elegant ramifi- cation of pedicled glands on the cuticle of the com- mon Provence rose, hence called moss-rose, is said to be only an accidental variation, caused originally by the kind being planted in a very damp and shady situa- tion : and it is affirmed any rose may be made mossy by keeping it constantly in the shade, and where the air is peculiarly moist from want of ventilation. 175 APPLICATION OF PHYSIOLOGICAL KNOWLEDGE TO THE VARIOUS PRACTICES OF THE CULTIVATOR. SECTION I. Sowing. THE components of a seed have been already noticed and described as consisting of the embryo plant, contained in one, or between two or more cotyledons, which are the kernel or farinaceous lobes destined to support the infant plant while it is establishing itself in the ground. These internal parts are protected, after separation from the parent, by two, often three investments, in the form of mem- braneous films, coriaceous coats, or hard woody shells. Although nature, in many instances, has made provision for the dispersion of seeds by furnishing them with volant appendages, or ejecting them from elastic capsules by which they are scattered to con- siderable distances around, yet there is no provision for covering them, except the fallen leaves, the tread- ing of cattle, or other accidents. They are shed where they grow ; and the season for ripening is also the natural season for sowing. This holds good with respect to every plant existing in its native habitat, as we find in the case of weeds ; but among the mul- 176 SOWING. titude of cultivated plants a great majority are exotics, requiring various and even unnatural seasons for com- mitting them to the ground ; as well as to allow time for the necessary preparation of the land, as for the seasonable uses of the crop. The vitality of seeds is more or less persistent according to the qualities contained in the body, or in the coverings. Some require to be sown soon after they are ripe ; others retain their vitality for many years, if protected from the changes and influ- ence of air ; but it is to be observed, that the longer they are kept in the granary or warehouse, the less vigorous do they rise from the seed-bed. The most vigorous plants rise from the most per- fect seeds. In all cases where mere bulk of wood, stem, foliage, or of flowers, is the object, the newest, ripest, and plumpest seeds should be preferred ; but if early flowers or fruit should be desired, older or artificially dried seed will best answer the end. Many are of opinion that provided the corculum of the seed be entire and iininjured, it signifies little how diminutive the cotyledons or quantity of albumen may be : for as soon as the embryo is fairly born, say they, it is instantly independent of the cotyledons. This is only partly true ; because a seedling, deprived of its cotyledons before it has expanded perfect leaves, is always seen to suffer from the loss of them. It must be admitted, however, that the siftings of peas, and thin berried turnip-land wheat, are both used for seed without any visible disadvantage. SOWING. 177 Full air, a moderate degree of moisture, and a tem- perature suitable to the kind of seed, are all neces- sary to perfect germination. The heat of the soil at seed time, whether in spring- or autumn, is generally between 40 and 50 of Fahrenheit ; and this is suffi- cient for corn and all other plants suited to the British climate. By dissection and close inspection of the germina- tion of seed, a pretty clear idea may be formed of the process. A certain degree of humidity softens the husk or shell : the constituents of air and water are absorbed by the cotyledons, and with the excitement of a necessary degree* of heat the whole swells ; the rostell protrudes through the integuments, and pro- ceeds or turns downward into the earth ; and soon after the infant stem rises into the air. The seed is matured by the parent by means of an umbilical attachment or cord; but whether the new radicles are an elongation of, or proceed from, this cord, the writer has never been able to ascertain. The size of seeds determines the degree of com- minution to which the surface soil should be reduced to receive them ; and also the depth at which they should be laid in. Large seeds, as those of the Spanish chestnut, require to be embedded at the depth of one and a half, or two inches ; whilst acorns, mast, and other such sized seeds and corn, require a covering of about one. This is a matter of more importance, and requires a greater degree of care in the performance than is commonly bestowed on it, especially in agri- N 178 SOWING. culture; because nature plainly shows us, that if seeds be either too much exposed to the air, or too deeply buried in the earth, their development must be imperfect. As the proper depth at which corn should be sown is of the utmost consequence to the farmer and to the nation at large, the manner of the development of corn seeds may be here portrayed, in order that the cultivator may be convinced that a proper depth is highly necessary to the success of the crop. The structure of graminous plants has been al- ready described ; here we have to show the difference in the development of a seed laid in at different depths. Fig. 50. A B C The figure A represents the growth from a seed which happened to be laid not deep enough in the soil, and consequently not having a sufficient hold SOWING. 179 thereof, becomes liable to be blown down by the wind before the ears are perfect. Figure B shows the development of a grain of wheat deposited at the proper depth. In this we see both the fibres and first stem issue from the same end of the grain ; the first spreading- themselves around, and the latter rising- directly and vigorously into the air. The sketch at C is that of a seed buried two or three inches deep. In this the first fibres are ejected as in the last ; but, being 1 too far from the air, the first internode of the ascending- culm is unnaturally elongated; and at the proper depth the second joint ejects the roots, which, with others produced from the joints above, perfect the plant. As soon as the secondary set of roots is formed, the first, being no longer useful, immediately perishes. Here we may observe that, though nature accomplishes her purpose of forming- roots at the due depth from the surface, yet it is at the expense of an unnecessary waste of power: and moreover producing a delicate member peculiarly liable to be the prey of insects and slugs in the soil before the crown roots are formed. It is this circumstance which so plainly points out the due depth at which wheat and other cereals should be deposited : and furnishes a good practical lesson to the farmer, never to sow before the harrows: or if he drills, never to allow the shares to go deeper than one inch into the ground ; or at least to see that the seed be not covered more than one inch. There is another circumstance in respect of wheat N2 180 SOWING. which shows the necessity and advantage of shallow sowing: it is this wheat is sowed, and sometimes late, in the autumn; if immediately after the plough, much of the seed falls too deeply and closely together between the furrows. The seminal roots are, of course, first put forth, the points of the first leaves appear above ground ; but the winter sets in, before the coronal roots are produced, and consequently the plant is only sustained by the first roots, and through that slender stem, , Fig. 50 C, amid all the changes and rigours of a winter's frost and snow. The coronal roots do not appear before the end of February or beginning of March, (the proper time for top-dress- ing wheat,) and all the time previous to this taking place, and during the severe season, the plant is in jeopardy as well from alternate frost and thaw, as from wire-worm, slugs, and insects in the soil. But in the case of sowing at the proper depth, the seminal roots are in their proper place, and are there much stronger; and granting that the secondary roots are not put forth till the spring, the plant has not that slender canal exposed to the attacks before alluded to. With respect to the proper depth for smaller seeds, if they be but just covered so as they receive at the same time a moderate share of the moisture always more or less present in mellow soils, it is enough ; one tine of the harrows in the field, and the smoothing action of the rake in the garden are all that are necessary for the generality of small seeds. Some very diminu- tive seeds only require to be pressed into the surface ; SOWING. 181 and which, if kept damp and shaded from the mid-day sun, will succeed better than if covered ever so care- fully. Almost all seeds require a well consolidated bed after being- well ploughed or digged, wheat and pulse particularly ; and this for two reasons : first because the seeds are equally affected by the close contact of the medium in which they are laid, germinate more regularly, and take a firmer hold of the soil ; and secondly, because seed-weeds are less likely to rise in a compact surface, than in one which is loose, nor can slugs or grubs work their way so well irr* a close surface. Hence the use of rollers, pressers, and treading loose ground with sheep among farmers, and the practice of treading in seed by the gardener. These are rules both in agriculture and horticulture ; at the same time, cultivators are aware that a fine, light, and dry soil is particularly favourable to the germination of some small seeds, more especially those of charlock (Sinapis arvensis) and common poppy (Papaver rhceds). Seeds in general are cast naked from capsules and glumes. The baccifera, pomifera, and drupiferous kinds undergo a preparation amidst the decaying pulpy coat with which they are surrounded. Those of the Coniferce do not escape from the woody strobile, till the scales enclosing them are opened by the sum- mer sun of the next year after they are ripe ; and if the cones are gathered, as they should be, before the seeds are shed, it requires some labour to split, kiln-dry, 182 SOWING. and thresh them, to discharge the seeds and prepare them for the seed-bed. A few seeds receive a preparation before sowing : and many, especially such as have been long in the warehouse, would, no doubt, be the better for it. The excitement from a dry soil is not always sufficient to awaken the vital principle. It is said, that some seeds will not vegetate at all without the extraor- dinary stimulus of passing through the stomach and intestines of an animal ! Be this as it may, we are well assured, that in the case of pulse seeds, their % germination is accelerated by being steeped in water for a few hours before sowing. Soaking the seeds for an hour or two in oxalic acid, or slightly watering them with it after being sown, is said to assist germination materially. Wheat is always prepared for sowing. This old custom is differently regarded by agriculturists as to its real object and efficiency. We hear nothing of brining and liming in old Tusser's time, 1575. Drawing the wheat seed, *". e. laying it on a table and separating the good grains from the bad, or vice rersd, was then the usual practice. This was the far- mer's and his family's task on evenings during seed- time, a most tedious process ; and no doubt gave rise to the custom of washing it, to separate at once the light from the heaviest grain. A lixivium made by the addition of common salt to the water was found best for this purpose of floating the light grains, smut-balls seeds, of weeds, and other extraneous SOWING. 183 bodies, all which could be easily skimmed off. The wheat seed being thus quickly cleansed, was immedi- ately dried by sifting- quicklime over it when laid on the floor, which got it soon in order for the sower. This is now an established custom ; and persevered in under the idea, that it prevents the disease called smut, though it has not been discovered in what way it acts as a preventive. Certain it is, however, the coating of salt and caustic lime does no injury to the seed, and may act as a defence to it against the attacks of birds and ground insects. Much of the success of planting depends on the choice of the seeds from which young trees are raised, whether species or varieties. The properties which are transferable from the parent tree to its progeny are various> viz., resemblance in form and colour of foliage, flowers, and fruit ; stature and mode of growth ; in peculiar texture of the wood, as to ponderosity, tenacity, and durability. Amongst cultivated varieties of edible fruit-trees, all the above properties are transferable by seeds, except the in- creased size and improved qualities of the coverings of the capsules and shells, and the robust habit of the shoots and leaves. The qualities of kernels used in the dessert, are generally transferable by sowing. When, therefore, any of the first-mentioned proper- ties of trees are required, seeds will convey them, especially if the seeds be taken from young vigorous trees, which exhibit the desired property most con- spicuously. Looking at the natural forests of Scotch pine, or of 184 SOWING. the common oak, we can see considerable diversity of habit and individual character. Some are conical and aspiring ; others are stag-headed and spreading. Such characters are conveyed by their seeds : hence it becomes the duty of the nurseryman, and the inter- est of every planter, to be careful in the selection of seed, whether intended for sale or sowing. There are certainly, for instance, two very distinct kinds of Scotch pine, one, of course, being a variety. The most common is of an upright and formal outline when young, and having a thick suberous persisting bark ; the second has a smoother bark in consequence of the outer layers being thrown off piecemeal during the growth ; it is also more irregular in form, and often presents an outline highly picturesque. One drawback against this last sort is, its liability to be shattered by the weight of snow lodging on the extended horizontal branches. The seeds of both sorts are gathered together, and it is not till the plants, raised from the mixture, are twenty years old, that their peculiar characters appear. So of the oak, Quercus rbbur, there are two varieties ( Q. sessiliflbra, and Q. pedunculate*,} in our woods ; the seeds of both are too often mixed and raised together, although the last is said to be a superior tree, producing the most valuable timber. These circumstances are mentioned to show the necessity of pure seed being chosen from the best specimens of the desired sorts, for the reasons above given. It may be imagined, perhaps, that as a seed con- SOWING. 185 tains a young plant, it will be free from the consti- tutional defects as well as the decrepitude of the parent ; but this we know is no less the case among vegetables than it is among animals. Defects fre- quently, and diseases almost always, are hereditary in both plants and animals. From an acorn of an aged oak a fine healthy tree may be raised, and which may arrive at even a greater magnitude than its parent ; but if the latter had any peculiar manner of growth, either good or bad, the former will surely inherit it. Although this be a general rule, it is not without exceptions. That variety of the Fraxlnus excelsior, called Pendula from the position of its branches, when worked and trained as an ornamental tree, is an accidental malformation of the growth, but which is not transferable by seeds ; for they, when sown, go back to the original. Almost all our culinary vegetables are varieties. Some are cultivated for the number, size, or close and early concentration of their leaves or flowers. Such are lettuce, cabbage, with its numerous varie- ties, broccoli, cauliflower, &c., and all salad herbs. The best, or rather truest of the sorts, are perpetuated by their seed, care being taken that on saving it none of their near alliances are in flower at the same time near them. Were this precaution not taken, the different sorts of the genus would be adulterated with each other ; and the present highly prized sorts would be finally lost. There is something unaccountable in comparing the fact of varieties and sub- varieties of herbs keeping 186 SOWING. true to the variations of the growth produced hy art and high cultivation, and the very different results which take place in improved fruit-trees, which can- not be reproduced by their seed. But in the latter case it must be observed, that the amelioration of the wild crab to that of the golden pippin apple, for instance, is not a change of the real fruit, that is, the seed, but an enlarged addition to, and an improved quality of, the pulpy covering of the pericarpium*. The same is the case of the pear, orange, &c. ; it is not the seeds that are altered by cultivation, but the character of their investments only. So that it appears by pampering the growth by high cultivation to produce larger shoots, leaves, and flowers, we also enlarge the integuments of the seed. The seeds themselves undergo but little change, especially in the cherry, apple, and pear ; though more in the peach, goose- berry, and some others. But if we cannot reproduce our improved fruits by their seeds, except by accident, we may obtain improved varieties from the same by impregnation ; the means of doing which will be noticed hereafter. Some orchardists are of opinion that the amelio- ration of fruit is only occasionally produced from im- pregnated seeds, and that the generality of our im- proved varieties have gained perfection gradually and in course of time, without other treatment than is commonly bestowed on orchard or garden ground. It is likely that the first fruit from a strong seedling * Seed vessel. SOWING. 187 may be more crude and colourless than when full crops have moderated the growth, and qualified the exuberant pulp ; but, as a general law, that fruit is improved by the age of the tree, we must take leave to deny. It may be remarked, however, that in the United States of America, old established orchards are said to yield fruits of superior quality, to those from lately planted orchards of the same kind of fruit. But that the seed of varieties of fruit-trees receive impressions from the pollen of each other, has been proved again and again, both by art and accident. By this means new sub-varieties have been obtained ; but it appears that the artificial impression extends only to the impregnated seeds, and not to their progeny. The seeds of Knight's Early Black Cherry, though originally obtained by cross-impregnation, produce, when sown, the common wild cherry, like all the rest of the same family. In this it is like almost all our other varieties and sub-varieties of cultivated fruit. Foreign seeds of curious trees, shrubs, or other plants, either tropical, or from very distant countries, are always found more or less damaged during the voyage. Some of them require soaking in water for a few hours before sowing, and all need a brisk hot- bed heat to prompt and assist vegetation. Nuts or hard-shelled seeds are sometimes assisted by having the points or bases of their shells Hied off before 188 SOWING. sowing. The spring- of the year is the best time for raising- exotics ; because they then have our summer to encourage and establish their growth. A properly chosen and well-prepared seed-bed is indispensably necessary for every kind of seed ; it should always be rich, as well as of a suitable tem- perament for their reception. The stronger a seed- ling rises, the better able is it to withstand the vicis- situdes of the weather. Many garden plants are raised in seed-beds, and from thence transplanted to where they are to stand for good. Some, like corn, are sown where they are intended to remain ; either in drills or broadcast. In both field and garden culture, drilling is certainly the best, as well as the neatest mode ; provided always that the seedlings be duly and timeously regulated in their inter-distances, according to the spaces respect- ively required. By such means all crowding is avoided, and every facility given for the operations of the hand or horse-hoe. Ridge-drilling that is, throwing two furrows together with the plough after the manure is spread, the seed being afterwards drilled along between is suitable for turnips, beet, &c. ; because the seeds are deposited not only in a mound of friable soil, but also in immediate contact with an accumulated portion of the manure, both favourable to the strong and quick growth of the seedlings. So necessary is it that every plant should enjoy its natural required space, that dibbing both wheat and SOWING. 189 beans is found a profitable practice. By this mode the seeds are more regularly disposed none are buried and a considerable quantity saved. Broadcasting, notwithstanding the very exact manner in which it can be performed by expert seedsmen, is liable to irregularity; not only from wind which may prevail, but from the inequality of the surface of arable land. Every hollow, and the furrows between the lands or ridges, always receiving more than their share of seed ; if not from the sower's hand, certainly from the action of the harrows. Unequal distribution occasions unequal growth, and consequently an unequal sample of grain. Seeds generally, and corn particularly, should neither be sowed too thick or too thin. If the former, every part of the plant is drawn and diminutive ; if the latter, on rich land, the corn becomes over-luxuriant liable to be laid more subject to blight and though the grain may be larger, it is always inferior in quality. Woods are sometimes raised from seeds. This is practicable ; but the success depends entirely on the necessary preparation being complete, i. e. perfect cleanness of the land so to be occupied. No weeds should have a previous hold of the soil, otherwise they will materially check, if not even destroy, the seedling plantation. Subsequent care and attention must be bestowed to prune and encourage the supe- riors draw out supernumeraries and remove all worthless encumbrances. 190 SOWING. A frequent change of seed is a necessary expe- dient in cultivation, in order to ensure the best returns. It is not only a change from one descrip- tion of soil to another, but a change from one country to another. Whatever may be the cause that foreign seeds and plants do better than home-bred is not easily guessed at ; but, taken as a naked fact, it is incontestable. A change of air and soil to a plant, seems to impart a new vigour, which it would not show in its native place. As a general rule in sowing, it may be observed in conclusion, when mere bulk and full form of the plant, whether tree or herb, is desired, sow thinly, and keep in open order ; when number, and superior quality of grain is the object, sow with a more liberal hand. Seedtime. It has already been observed, that the season of ripening is the natural time for sowing seed ; but this is seldom necessary to be attended to, except in the case of a few curious plants. Our seasons, and the purpose for which plants are culti- vated, regulate the time or times of sowing. Of some plants we only require the seminal, of others the perfect leaves. Young tubers, unripe pods, seeds, fruit, and flowers of many, and the perfectly mature seeds of others, are obtained by timeous sowing, and at periods fixed by the practical knowledge of cultivators. 191 SECTION II. Transplanting. Almost all our cultivated plants being- raised from seed, or by other modes of propaga- tion in seed-beds or nurseries, are from thence re- moved to their final stations by transplantation. The best time for this work is when the plant is at rest, viz. from the time the growth ceases in autumn, till its recommencement in the spring. An old proverb says " He that would a good tree have Should bury the old leaves in the grave." meaning that the fall of the leaves being a sign that the plant has entered on its winter rest, is the best season for removing it. This is spoken of deciduous trees ; but it is unquestionably the best season also for the transplanting of evergreens ; not only be- cause the summer growth has ceased, but also because there is less sunshine, and less danger of the fibrous roots being damaged by drying air during the removal. Success in all cases depends on the preservation of the young fibres, expedition in the removal, and seeing that the soil of the new site is sufficiently moist to encourage the re-striking of the young roots. The younger a plant is, the easier and more safely is it transplanted ; merely because it has but a slight hold of the ground, requiring no violence in taking up, and being extremely vigorous, readily lays hold of its new place. Herbaceous plants, whether young or 192 TRANSPLANTING. old, may be transplanted at any time, without risk of any thing 1 , except perhaps their flowers, though it is best done when the plant is at rest. The great advantage of transplanting trees in early autumn is, that though the leaves are fallen, and the visible growth stagnant, still it is observed that the roots are not entirely asleep ; new fibres are exserted from new planted trees, even in November : these assist to establish the plant in its new place, defend it in some measure from the storms of winter, and pre- pare it to start with greater vigour on the return of spring. Both fruit and forest trees, may, however, be transplanted any time during the winter months when the weather is mild and open ; but no planting should be attempted while the air is frosty. From the description already given of the formation of roots it will be quite obvious that the delicate ex- tremities or fibres are most liable to suffer on being removed from the soil. To save them entire requires all possible care ; because the less damage they sus- tain, the less will the plant feel its removal. But as it is impossible to transplant a tree of any size so care- fully but that some of the roots will be bruised or broken, and the whole receive a check, it is the planter's duty to give a little pruning both to root and head. The branched head of a tree and its system of roots , are " correlative parts ; " they mutually depend on each other ; simultaneously progressing or stationary. The circumstance of being equally balanced, as to TRANSPLANTING. 193 their respective powers, constitutes the health of the plant. If the roots be diminished hy any violence, the head must lose a part of its supply of nourish- ment; and from the want of this it becomes and remains languid until the roots recover and resume their usual functions. If, therefore, any of the prin- cipal roots are broken in taking up, the stumps should be smoothly pruned off, to ensure the ejection of new fibres therefrom : a result which invariably takes place if the plant be healthy and favourably situated. But whether the roots be broken or not, all the work- ing outlets are more or less damaged, and conse- quently incompetent to give their wonted assistance. In this case the practice is to reduce the head by pruning, so that no more should be required of the roots than they are able to afford. Practitioners differ in opinion as to whether this pruning of the head be right or wrong ; and also about whether it be best done in the first or second year after planting. Those who attribute all accretion to the agency of the leaves, deem it extremely erroneous to deprive a plant of any part of the foliage : and therefore insist, that to cut off the shoot that would be soon covered with leaves, at the moment too, when the languid roots need the utmost excitement would be, they think, actual murder ! On the other hand admitting, as we must do, that the expansion of leaves invites the ascent of the sap, and thereby calls on the roots, as it were, to render instant o 194 TRANSPLANTING. supplies ; yet if this demand be made when the roots are in no condition to meet it, the consequence is a very feeble expansion of both leaves and shoots, evincing a general debility of the whole system. Those, therefore, who believe that these are the cir- cumstances of a newly transplanted tree, advise the pruning down the last year's shoots that were pro- duced by fibres now torn and useless, and which will not only lessen a demand that cannot be answered, but ensure the production of a new set of organs, viz. new roots and shoots, to come into play, and which will assuredly progress together with greater vigour. Those who hold the opinion, that depriving a tree of any portion of its foliage is an injury, and that therefore cutting it in the second year is preferable to pruning it in the first, appear to argue inconsistently : because if pruning be detrimental in the first year, so must it also be in the second. Still we know many excellent practitioners in the market gardens about London (and none do better than they) in managing their newly transplanted standard fruit trees, defer pruning down until the second year ; and even not then unless the weakly state of the tree renders pruning necessary. And their reasons are these : a tree whose root has been established for twelve months, shoots with greater vigour after pruning, than a newly planted one : and should the trees take well to their new stations, which they seldom fail to do in such rich and highly cultivated ground, pruning TRANSPLANTING. 195 is unnecessary, because it would certainly delay the period of their bearing, a circumstance not at all desirable to a market gardener. This horror of cutting off leaf-bearing branches is an interdict against all pruning. The doctrine may be regarded by the forester ; but what is the orchardist to do when he wishes to renovate his old trees ? His readiest expedient is decapitation, in order to obtain a new and extended head, either by regrafting or not- But what are the practical facts showing that the above ideas of the state of a transplanted tree, and the propriety of pruning it as soon as transplanted, are correct ? Several, we think, may be adduced. A cutting may be aptly compared to a newly transplanted tree ; both are destitute of active fibres ; in fact, both have these necessary organs to form before either can make any progress in growth. In this respect they are like a seed, which, in its development, first ejects its rostel into the ground. Would it assist the root- ing of the cutting of any shrub or tree were the whole length of a shoot taken instead of a part ? and would the same cutting or shoot of a deciduous tree have been more readily rooted while it was furnished with leaves, than after they had fallen ? To both these questions, in respect to deciduous trees, the practical man will probably answer in the negative. Besides, with respect to the transplanted tree, but little assistance being derivable from the enfeebled roots, is it not better to concentrate this limited supply, and direct it to the production of a few new 196 TRANSPLANTING. shoots than allow it to be diffused and neutralised over the debilitated shoots of the former year ? Let us observe what new vigour is imparted to a bud, graft, or cutting, taken from a tree, or a shoot from an old stool of an herb by being separated from the parent and placed in a situation favourable to its habit and condition. In its former station it only received a share of the nourishment yielded by a large system of roots ; in its new place it depends on attachments to a youthful stem, or fibres formed by itself, and becomes an independent being, and expands in all the force of youth. So it is with a new planted young tree ; by pruning the roots a set of new active fibres is produced, and by cutting-in the last year's shoots, when both are necessary, fresh ones come forth in connection with the new fibres, both progressing vigorously together. This plain statement, sanctioned, moreover, by being pretty generally acted upon, is, nevertheless, very differently understood, even among practical men. There are two circumstances which have pro- bably caused this difference of opinion : the first is, the imputed efficiency of the leaves in vegetable economy ; and the second, an unheeded fact, that old trees require less pruning of the head on removal than those that are young. This latter circumstance, by the by, is easily accounted for, and is evidently as follows : old trees, say of twenty or thirty years' growth, always contain a store of coagulated sap in their stem and branches ; this becoming fluid on the TRANSPLANTING. 197 approach of spring 1 , as is the case in all healthy trees, furnishes the requisite supply for the expansion of the buds and leaves, which is all that is expected of a recently transplanted tree of a large size. The summer is far advanced before intercommunication can possibly take place between the root and branches of such a tree ; so that it may be said to live through part of the summer upon its previously received store of sap, without any assistance from the root at all. That this is a fact, may be inferred from what we may see every year in the timber yard, namely, vigorous young shoots produced by the butts of elm and other trees for a year or two after they have been felled, and consequently deprived of all assist- ance from their root. This circumstance has given some very intelligent planters reason to infer, that the more a large tree is pruned the worse it succeeds ; and we have no doubt (in the case of several kinds of trees) the observation is just, provided the newly transplanted large tree can be kept perfectly steady in its new place. Old trees are transplanted either for the purpose of embellishment, or to save the life of a favourite which happens to stand in the way. It is not ex- pected that its volume will be increased on the instant ; to preserve it in form and alive till it is re-established is the sole aim. Its bulk and inherent store of vitality render severe lopping of the head unnecessary. But with young trees we have other views ; we endeavour to start them with renovated 198 TRANSPLANTING. strength by the means of a careful taking up, well prepared soil to receive them, and a judicious pruning of both roots and head, solely for the purpose of increasing their volume. The old custom of severely lopping transplanted trees of considerable size was with the double intent of reducing the head to an equality with the damaged root, and to lighten it against the power of wind. This rule was oftentimes too indiscriminately and extremely applied ; and, consequently, such severe dismemberment brought on a partial or total paralysis, which killed the tree. Besides, some forest trees cannot bear pruning at any time, unless the whole branch is cut smoothly off: such is the beech. The foregoing remarks on the necessity of cutting in the head of a new transplanted tree in the first year are only applicable to young fruit trees, of the usual size and age, when taken from the nursery to the orchard or garden. On the general propriety of doing so, there need be no doubt; but the exact manner of doing it cannot be defined, because much depends on the condition of the tree, and the manner in which it is intended to be trained. Young forest trees, when transplanted, require but little pruning ; those of the Conifer ce none at all. Deciduous kinds should have irregular laterals cut off close, not only to give supremacy to the leading shoot, but to make the young tree less liable to be shaken by the wind. Much has been written on the subject of trans- TRANSPLANTING. 199 planting large trees, and many wonderful feats in this way have been performed, both in ancient and modern times. Naked lawns have been diversified, and groves formed in the short space of a few months ! Such performances go to prove that, with requisite care, skill, and physical force, properly directed, any tree of moderate size, i. e. from twenty to forty feet high, may be transplanted with safety and success. One precaution very much facilitates the execution ; it is that of digging a circular trench, at a proper distance, say six or eight feet, round the trunk and deep enough to be below, and to cut through all the roots except three or four of the largest, which are left at equal distances to act as spurs for the better security of the tree when placed in its new situation. The trench, after the stumps of the roots are cut neatly off, is filled with previously prepared compost for the new fringe of fibres to strike into; and after one, or, what is better, two years, the tree may be with ease and a fine appendage of young roots taken up. In doing this a deep trench on the outside of the first is made, into which the mould among the roots is drawn, until the whole root is loosened from the soil. The spur roots are at the same time followed out and laid bare. A timber truck on high wheels is then backed against the stem, its pole raised and bound thereto ; the wheels must be between, not upon any of the roots ; and when all is ready a horse, or two if necessary, are hooked to the chain attached to the end of the pole, or to a rope fixed round both pole and stem 200 TRANSPLANTING. of the tree, by which the latter is pulled down upon the truck, in which position it is drawn away, root foremost, to its new place, previously prepared to receive it. In replanting the tree much depends on the care and order of laying- out the roots, each in its natural direction, and all firmly embedded in the mould, giving water as the work proceeds till all is compactly covered up. As the tree will require to be frequently watered during the summer, the surface round the trunk should be left rather hollow to retain it. It is generally observed, that trees transplanted during their most vigorous growth, i. e. after they are ten or twelve years of age, never arrive at so full stature, but take a precocious maturity of form long before they gain that age in which their charac- teristic form appears. This we sometimes see in pleasure grounds where large plants have been chosen for immediate effect. It is for this reason that very young trees are preferred by planters to large or older ones ; and for the same reason also it is that trees, raised from the seed where they are intended to remain, always make more stately timber than such as have been transplanted at any time. This is quite consistent with our ideas respecting the constitutional structure and development of plants. Every tree, shrub, or herb, according to the suitableness of its situation, has a determinate form and volume. They arrive at this through the differ- ent gradations of youth, perfect form, and full bulk, TRANSPLANTING. 201 whence they fall to decay. If they be transplanted whilst in the midst of the first stage a certain tem- porary pause must take place, inducing-, no doubt, a consequent decrepitude, imposing the feeble exertions of age instead of the vigorous efforts of juvenile health. Frequent transplantation of young trees and shrubs in the nursery prepares them for subsequent removal; and although this may affect the ultimate growth of forest trees in a trifling degree, it is highly useful in promoting early fruitfulness in those of fruit. It is hardly necessary to add, that all plants are affected by the circumstances of soil and situation in which they are placed. A strong loam on a clay sub- soil is suitable for the oak ; a loamy gravel is best for the ash and elm ; a calcareous gravel on chalk is the natural bed for the beech ; and we see poplars, willows, and alder luxuriant in bog-earthy valleys. All trees arrive at the greatest height in sheltered valleys ; but in proportion as they gain altitude they are diminished in diameter of stem ; the reverse of this takes place on exposed situations. The latter are also more hardy ; and it is observed of both trees and shrubs of a luxuriant habit, that they withstand the effects of frost better than such as are weakly ; and if the roots in both cases be securely defended it is also a protection to the head. This may be sup- posed to arise from the more copious currents of warm air received into the system through the roots. 202 PROPAGATION. Repeated transplantation of herbs has a tendency to increase their spreading- or stocky bulk rather than their aspiring growth ; as exemplified in many species of our culinary plants, as lettuce, broccoli, &c. The reason seems to be their expansion, that is the elon- gation of their stem, leaves, and roots, receiving fre- quent checks, induces new births of roots, a shorter stem, broader leaves, and, in the case of most sorts of broccoli, larger flower-heads. A very frequent error is committed in trans- plantation by placing the root too deep. This is well known to be hurtful to the plant ; indeed so much so, that there is no readier way of killing a tree than by burying the roots. SECTION III. Propagation. Nature has provided for the per- petuation of every species of plant found on the face of the earth, chiefly by dissemination, and also by viviparous progeny parted off from the parent station. Among all plants exisfing in a state of nature these processes go on constantly and uniformly without human interference ; but when they are domesticated and brought into cultivation for the peculiar uses, directly or indirectly, of man, their original habits, forms, and qualities become so changed, that much variation ensues. Some of these variations are en- largements of the stem or of the leaves ; others of PROPAGATION. 203 the flowers and seed, or of the appendages of the seed vessels. These variations, if considered improve- ments, are more or less valued, and consequently become interesting objects of the cultivator's care. Many variations which take place among herbs are perpetuated by their seed ; but among improved fruits and flowers their seed, as has been before noticed, does not convey those variations in quality, form, and colour for which they are valued ; and consequently the cultivator is compelled to have recourse to other expedients to preserve and continue the excellencies he regards. Varieties are propagated by cuttings, layers, and by grafting and budding. All these practices have for their object the forming a new plant of the im- proved variety by placing a part of it in the ground to take root, or by grafting or budding it upon a kindred stock. The methods of performing these expedients being so well known need not be described here. But as their practicability depends on the constitutional powers and organisation of the plants so propagated, these properties require to be noticed. Cuttings. All exogenous trees and shrubs may be propagated by cuttings, whether the stems be jointed or simple. Some kinds form roots readily from any part of the stem, others with more diffi- culty, owing perhaps to the resinous or some other quality in the sap, which soon becomes corrupt when placed, as cuttings usually are, in the soil. 204 PROPAGATION. The process by which a shoot or part of a shoot, a single hud, or even, in some cases, a single leaf, becomes an independent plant, is owing to the con- stitutional powers of the vital envelope of the system. This member, as has been before observed, possesses the faculty of protruding its lower part downward, or ejecting slender portions thereof into the ground, having all the members and powers of those roots which are produced from the corculum of a seed. The first roots produced by a seed proceed from that part of it called the rostellum, but how radicles are generated from the bottom of a cutting is not so easily conjec- tured. They issue from the vital membrane, but in what manner it is difficult to describe. The proper depth at which cuttings should be put in cannot always be strictly attended to. Exotic cuttings, raised under the protection of glass, may, and commonly are, put no deeper into the soil than is suitable, that is just within the surface ; but those of hardy plants are generally, for the sake of security, let in deeper than the ready striking of the cuttings require. It is worthy of remark, that the same distance below the surface which is so suitable for the healthy germination of seed, is also the most favourable for the ejection of the roots of cuttings. It seems that a certain modified influence of the atmosphere is necessary in both processes. Cuttings of gooseberries, common laurel, &c., when taken up after they are struck, appear rooted as Fig. 51, PROPAGATION. 205 Fig. 51. showing that though roots are produced at the base, many are also emitted from the place near the sur- face above alluded to. The advantages of propagating by cuttings is the ease and expedition with which it is done. Several kinds of trees and shrubs are raised from truncheons, i. e. large poles or branches, as the willow, elder, mulberry, &c. The circumstance of shoots taken from the top of a tree so readily emitting roots when placed in a suitable situation, is proof that the principles of roots are present in every part of the simple stem, above ground as well as below. Whether the radicle fibre exists in an identical state in the envelope, or 206 PROPAGATION. whether it is a filamental protrusion of its substance only, is uncertain. We have stated repeatedly, that that vital member descends with more celerity than it proceeds in any other direction. Its appearance on the disbarked stem of a tree shows this decidedly; it flies from light, and seems to luxuriate in dark- ness. At the base of a cutting, it often issues out before the fibres are emitted ; and sometimes a cutting will keep alive for several months, without other change than having this protuberance at the lower end. It has been stated by some writers as a fact, that the fibres formed by a cutting, appertain to the buds situated above, in an especial manner. This idea has been alluded to before ; and here we have only to repeat, that though extremely plausible, it is not easily proved. If, indeed, radicle fibres were never exhibited in the absence of buds, we might be led to adopt the opinion ; but when we see simple leaves, those of the Camellia for instance, emit a fringe of fibres without the assistance of either bud or stem, we are compelled to doubt its accuracy. That these essential parts progress together, and that they are intimately connected, is perfectly obvious ; but they are distinct organs nevertheless. It may just be observed here, that the fibres produced from single leaves, appear to be ejected from the incised part of the petiole, which shows that slender portions of the envelope are even protruded into the leaves. Cuttings of stove plants are sometimes readily rooted, by being placed in small phials of water sunk in the bark, or hot-bed. Experience has fixed the PROPAGATION. 207 rules, as well for choosing the parts of plants proper for cuttings, as the time for putting them in the ground. Those of trees and shrubs may be made of either the points, or any part of the present year's shoots, and put in the ground in autumn, or in early spring. Cuttings of delicate greenhouse, hothouse, or herbaceous flowering plants, are mostly made of the points of the growing shoots. There is in all young shoots of either woody or herbaceous plants, a certain part of them which more readily emit fibres than others ; this is where it is not so tender as to be liable to rot, nor yet so indurated, as that the vegetative power is enfeebled. Heaths, and many other green- house and hothouse plants pinks, and all similar plants in flower borders, are propagated on this prin- ciple. Layering. Plants which do not readily strike root by cuttings, are propagated by layers. The difference is, that whereas the cutting is completely separated from the parent, the layer is only partly so. It is a certain and safe process ; because the layer is supported by the stool from which it is laid down, whilst new roots are exserted from an incision made in the shoot, to permit their escape. Layers, like cuttings, convey the true properties of the mother plant ; for which advantage it is in many cases a superior mode to either grafting or budding. One method of layering may be described, which is found particularly successful in the propagation of some flowering shrubs, viz. : the shoot to be layered 208 PROPAGATION. has circular incisions made above and below each bed along its whole length ; it is then pegged down on the surface of the ground, and lightly covered with a sandy compost. Each bud will produce a shoot rising erectly in the air, and root fibres being at the same time ejected from the incisions, independent plants, separable in the autumn, are soon formed. The long sucker-like shoots of rose-trees are well calcu- lated for this mode of propagation ; and as some sorts of these eject roots sooner from young than from old wood, practitioners omit ringing the bark, and wait till the young shoots produced from the layers are five or six inches long : a tongue incision is then made at the bottom of each, and embedded in sand, they readily make roots ; the old layer remaining to produce other shoots, which may be struck in like manner. Grafting. This is a very ancient custom. When the fruit-grower found that he could not continue his improved fruit by sowing their seed, he had recourse to engrafting a shoot of the favourite upon any wild kindred stock. The advantages of grafting are many, saying nothing of the facility and success of the ope- ration it induces moderate growth and early fruit- fulness ; instead of waiting a long period of the ado- lescence of a seedling, we have at once the matured head transferred to a young root ; and if an old tree be of an inferior kind, or become decayed through age, it may be lopped, and regrafted with one or several new or superior sorts. The practicability of grafting depends on the rea- PROPAGATION. 209 diness with which the cellular elements of the scion and stock unite. The envelope of the former imping- ing on that of the latter, at the season when both have begun, or are about to begin, to swell under the flowing sap, instantly amalgamate and coalesce. If the scion and stock be nearly of a size, the junction becomes so complete, that in a few years it is scarcely discernible, more especially if both are equal as to their habit of growth. But if one be of a more robust habit than the other, they increase in dia- meter unequally. If an apple scion be grafted on a whitethorn, or a pear on a quince stock, the grafts in both cases are engrossed much faster than the dwarfer Fig. 52. Perpendicular sectiou of a graft inserted on a dwarf stock. P 210 PROPAGATION. growing stocks ; of course the junction is always apparent, and sometimes extremely dissimilar. This seems to be owing to the unequal character of the cellular and vascular fabric, as Fig. 52. There is a free intercommunication of the juices ; but the specific difference of the ligneous structure causes the disparity in the annual accretions. So with respect to a graft of a dwarfish or slender-growing species inserted in one of more vigorous habit, as the Daphne Cnebrum on the D. Laureola, the contrary effect takes place ; while the scion puts forth its atte- nuated branches and feeble stem, that of the stock is incrassated to twice the size. The sap-vessels on the bark and wood of both graft and stock being numerous, can hardly miss coming in contact when so united ; and the prompt inter- junction of the cellular matter anastomoses the whole together. On examination of the grafted part of a stem of several years' growth, by cleaving it perpen- dicularly, (Fig. 52,) or cutting it transversely, we see that there is an intimate union between the layer of wood, which was about to be formed when the opera- tion was performed, and of all the subsequent formed layers of both ; but between the wood of the graft and stock which was formed before the performance, although closely and soundly adhering to each other, there is a visible juncture, marked by a brown -coloured line where the two surfaces made by the knife were joined. The union of these is, however, no more than a simple adherence by means of secreted sap PROPAGATION. 211 acting- as a cement, not certainly by interj unction of the ligneous fibres. A very interesting- problem on vegetable physio- logy is, whether the stock is affected by the graft, or the graft by the stock. In most cases, we observe no change whatever, any more than if the grafted tree had been raised from a cutting or a layer. No change takes place in its habit, nor in the form of its leaves, flower, or fruit. It receives from the stock appa- rently the same nutriment it would have received from its parent branch, supposing it to have been selected and left to form a principal head thereon. This is invariably the result of a union of congenial stocks and scions. But when this last-mentioned particular is not attended to, very different effects are observable. Some of these have been mentioned before, and which convincingly show, that the graft may be either invigorated or dwarfed by stocks un- congenial in habit with itself. The operation alone induces moderate growth ; because in choosing scions we take, or should take, them from the mature and most fruitful parts of the tree we wish to propagate, and not from the rank growing shoots of the stem, or from the centre of the head. Plants have all natural habits ; and some of them, fruit-trees among the rest, have what may be called incidental habits. The pendent position of the weeping ash, as before observed, is incidental. This deformity can be trans- ferred by grafts ; so any peculiar habit in the growth of fruit-trees may be transferred in the same w r ay. p 2 212 PROPAGATION. The crooked, dangling shoots of a jargonelle pear, for instance, should not be chosen for grafts ; nor should those of any other tree be selected which do not show the desired properties as well in habit of growth as in those of perfect health and maturity. That the character of the stock affects the growth of the graft is well known. Rampant growing, and consequently barren fruit-trees, by being worked on dwarf-growing stocks, are greatly improved for the purposes of the fruit-grower ; and the reverse of this practice, i. e. placing weakly growing kinds on robust growing stocks effects a similar improvement. These counter dispositions affect only the growth of the sorts united to each other by grafting ; but such unions produce other remarkable consequences. One ot the most curious is the well-known circum- stance of the variegation of the colour of the graft appearing on suckers which rise from the roots of the stock. This circumstance shows that there is some inter- communication between the head and root, and must be, it is supposed, caused either by a descent of some member of the graft, or of its sap. No detachments of the wood or bark can possibly be prolonged down- ward ; because, as soon as these members are formed, they remain ever after unchanged longitudinally. The vital body is only capable of being so extended ; but whether as fibres, or in any other way from the graft or bud, it is difficult to conceive. If such a process obtains in the jasmine, we may expect that some- PROPAGATION. 213 thing similar might be observed in other trees. Such a circumstance, however, admits of easy proof, though it has not been sufficiently tried ; because if we graft a pear on a quince, in a series of years the original axis of the quince stock will be covered by the annu- ally or occasionally downward prolongations of the pear ; and if then a cross section of the stem below the graft be made, the wood of the quince will ap- pear in the centre, surrounded by that of the pear, the original bark of the stock remaining on the exte- rior. But that this does take place, is positively denied ; no portion of the substance of the graft is ever seen to descend much below the place where it is united to the stock ; and therefore some other cause must be assigned for the appearance of variegated leaves on the suckers. A curious experiment, long ago performed by Du Hamel and others, has lately been made, by extract- ing a hoop of bark from the sycamore- leaved maple, and substituting another of equal size of red maple. A perfect union took place ; and, after some time, the part was examined ; and the new wood formed under the red maple bark was found to be that of itself, and not that of the sycamore, which it would have been had ligneous fibres of the latter descended from its buds above. Observations sur la Structure et la Mode cT Accroissement des tiges dans quelque Families de Plantes Decotyledones. Par M. Adolphe Brong- niart. Acad. de Scien. Paris. On this experiment we may remark, that it point- 214 PROPAGATION. edly controverts the idea that the new zone of wood is formed by fibres, which descend from the buds of the higher parts of the tree ; and secondly, we may state our opinion, that the result showed that the vital envelope of the sycamore was removed with its bark, and that of the red maple put in its place, otherwise no new wood of the latter could have been formed beneath. Had the bark of the red species been placed on the undisturbed envelope of the syca- more maple, supposing this practicable, the new-formed wood would have been that of the last-named tree. The difficulty about change of the colour of leaves is easily solved by saying that the taint (or disease as it is considered to be by botanists) is carried down by some partial subsidence of the sap. And though there may he rational doubts of the possibility of sap convey in g forms from one part of the plant to another, it may be admitted that it is capable of conveying those chemical oxygenating qualities which may change green to yellow coloured leaves. Certain influences have been attributed to the stock as either improving or deteriorating the fruit of the graft. It is said that pears from a quince stock are more austere than such as are produced by the common pear stock ; and there are other accounts on record of apples being altered by the stocks on which they are worked. But none of these reports have been so far confirmed as to have any rule of practice founded upon them. One eifect of double working fruit trees has been proved by nurserymen ; PROPAGATION. 215 viz. that if a late peach be budded on an earlier kind, it will ripen sooner than if worked on a plum or com- mon stock. This, however, may rather be the effect of double working-, than from any precocious virtue it may receive from the intermediate stock on which it is placed. Experience shows also that if a free-growing graft be placed on a diminutive growing stock, the roots of the latter will be greatly enlarged in conse- quence. This is a proof that the energy of the root is excitable, and in most cases depends in its develop- ment on the demands of the head. ^ The practice of cross-working fruit-trees has not yet been carried so far, perhaps, as it might be. This is a fine field for experiments which may lead to use- ful discoveries and important results ; especially in the preparation of young fruit trees for forcing, or for houses or walls of limited extent. Grafting is performed in many different ways according to the size of the stock to be worked, or to the susceptibility of the plant to succeed under such an operation. For large or old trees, crown and clift* grafting are best adapted : the last is preferable, because there is greater security for the grafts against the effects of wind. Plants that do not readily take by the ordinary modes are grafted by what is called u grafting by approach," or " in-arching ; " this is * Both these methods of grafting are also suitable for very small exotic plants, 216 PROPAGATION. when the plants to be operated on stand near, or which may be brought near tog-ether, the shoots of each, by having equal sections taken off at the most convenient point of contact, firmly and exactly bound together, and clayed, will soon unite and allow of the graft being separated from its native branch. An ingenious and much more convenient method of grafting by " approach " has lately been practised- The graft is cut off the mother plant ; but instead of the lower end being inserted into the stock, it is at- tached thereto by its middle and bound securely : a small phial of water is then suspended to the stock and in which the base of the graft is kept plunged. This supplies the graft with aliment till the connec- tion between it and the stock is completely formed ; and so effectual is this assistance to the graft, that fibres are produced from its lower end in the water, and of which (the lower end) a separate plant may be made when taken off. Escutcheon, or shield grafting, is raising a triangu- lar piece of the bark containing a bud> and inserting it into an opening of the same size made to receive it on the stock. Root grafting is sometimes convenient. Instead of using the stem of a stock a root of it only is suffi- cient ; this, grafted in the usual manner, tied and clayed, and replanted in a suitable place, will not fail to take. Where proper stocks cannot be had, a favourite plant may be propagated by grafting some of its shoots upon parts of its own roots which can PROPAGATION. 217 be spared for the purpose. Much may be done in this way among exotics by an ingenious cultivator who may have a hot bed to plunge his root-grafted plants into : such a stimulus greatly assists operations of this nature. Whichsoever manner of grafting be adopted, the success principally depends on the congeniality of the stock and graft, on the proper season chosen for doing it, and on the precision and expedition with which the operation is performed. Reverse grafting. Nothing shows the anastomos- ing properties of the cellular membrane, when actuated by the vital principle, so convincingly as the instance of reverse grafting. By placing a graft on a stock in this unnatural manner a perfect union takes place and the future development of the graft is carried on in the same way as that of a reversed shoot. In this case it is perceivable that, if there be special sap vessels, they can re-convey as well as convey the juices either upwards or downwards ; or if there be no such vessels, it is evident, as has been before stated, that the cellular frame is permeable by sap in all directions. Another proof of this is exemplified by the long rambling shoots of the common bramble, which, as soon as their points rest on the ground, strike roots and assist to amplify the shoot by a backward flow of nourishment. Budding Differs from grafting in this, that, whereas by the latter, a shoot or part of a shoot 218 PROPAGATION. having several visible buds is transferred to the stock, by the former we transfer but one. Grafting is best performed in the spring just as the sap begins to be in motion ; budding is done most successfully when the cambium or new layer of wood has gained considerable consistence, and from which the bark is easily raised. Some plants, chiefly our stone fruit trees, if wounded through the bark while the growth is stagnant, or before the living cellular matter of the envelope is in motion, do not readily heal. The wound becomes an inveterate sore, discharging for a long time the sap which be- comes inspissated into gum by the air, at once exhaust- ing the tree, and detrimental to the adjacent organisa- tion of the system. Grafting such trees at the usual season, is therefore impracticable; but budding is eligible merely because the wound made in the operation is quickly healed, and the practice otherwise almost always successful. Budding is only a modification of grafting, and suc- ceeds upon the same principle being followed, viz. placing the vital members of the two plants in contact to form the desired connection. The bud to be inserted is cut off a properly ripened shoot, and after being freed from a thin slice of wood that comes off with it, is placed in an opening made in the bark of the stock to receive it. Thus it is placed in nearly the same situation on the stock, that it had on its native branch ; the inner bark and vital envelope of the bud resting on the envelope of the stock ; the outer bark of the PROPAGATION. 219 latter being first opened to receive and afterwards folded over the inserted bud, all being firmly bound by a ligature. Some practitioners omit taking away the wood of the bud lest it should injure its woody axis, on the preservation of which ihe whole future development depends. This omission does not much signify, pro- vided the bud be laid close to the wood of the stock, to do which the vital envelope must be raised along with the bark to admit it : but the better way is, certainly, to prepare the bud in the usual manner, and seeing that it is perfect, place it on the swelling envelope ; which last should be disturbed as little as possible in the operation. The effects of budding on the future tree, as well as in the circumstances arising from buds being asso- ciated with diminutive or rank growing stocks, are quite similar to those of grafting. By budding, a maiden tree is produced in the second year, by graft- ing, in the first. The former is suitable for all trees having a gummy, the latter for such as have an aqueous sap. In the management of exotic plants, whether cul- tivated for their flowers or fruit, the effects of budding and grafting are of the greatest consequence to the cultivator. It has been shown that both operations induce diminutive growth ; a convenient circumstance for our glazed houses of limited extent ; and as grafts or buds are selected from the highest matured branches of the tree intended to be propagated, this 220 PROPAGATION. also gives a chance of seeing- the flowers and fruit sooner than they might appear on an unworked plant. Tropical fruit trees seldom show flowers in our collec- tions, because there is not sufficient space allowed them for that expansion of branches which usually precedes the production of fruit : therefore, whatever tends to diminish their natural stature, and expedite their flowering, is a requisite point of good manage- ment. Pine-apples we can have in this country in as great, if not greater perfection than in their native climate ; and this because they are not a tree fruit, require but little space, and quickly arrive at full age. The peach, grape, and fig, are almost naturalised, and need only the protection of a wall assisted by a glass case to ripen them. The orange and its affinities require only to be defended from frost. But the mango, mangosteen, jambosteen, cherimoyer, and several other excellent tropical fruits have not had in Europe, perhaps, that management of which they are susceptible, nor care bestowed which they deserve, and which, doubtless, would effect their maturation in our pineries, or, in what would be better, a stove constructed for the purpose. It is among these last mentioned fruit trees, that the skill of the gardener with his knife and working operations (i. e. grafting and budding) would effectuate so desirable a result 5 and the practicability of such manoeuvres only requires to be mentioned to induce proprietors who have the taste and means, and the gardener who has opportu- PROPAGATION. 221 riity to make the trial, in order to add to the delica- cies of his employer's table. The only other methods of artificial propagation are performed on herbaceous plants. Bulbs which do not produce offsets readily, or from which offsets are re- quired, are managed so as to yield them plentifully by cutting off the upper half of the bulb. This prevents flowering and prompts the viviparous principle into extraordinary action, so that a numerous progeny are produced. Tubers having many buds, or eyes as they are called, are separable into as many sections as there are eyes, so that they may be propagated to any extent ; and to show the vast complication of gems existing in a tuber of, or in a single eye of a potato, we have only to instance the means pursued to mul- tiply a new or favourite sort when only a few, or a single one is possessed by the cultivator. In the month of April, or earlier, the tuber is placed in a mild hot-bed ; and as soon as the shoots that rise in succession from it are three or four inches long, they are slipped off and planted out in open ground. This planting of slips may continue till the beginning of July : for so long will the tuber continue to throw up shoots in number almost incredible ; each eye throw- ing up many stems, which are all separable as inde- pendent plants; and, thus detached, yield a far more numerous return of tubers than would have been produced by the mother disposed of in any other way. Tubers of congenial natures are capable of being grafted on each other, and are sometimes useful in the 222 PRUNING. propagation of curious varieties of Georgina, Pcebnia, and the like. SECTION IV. Pruning. The pruner should be a good vegetable physiologist ; unless he has an intimate knowledge of the components of the plant their tendencies and functions in the system, his operations will always be performed in the twilight of uncertainty. There are, however, many expert pruners who have no pretensions to be called scientific physiologists, and who, notwithstanding, perform the work with the utmost propriety, merely because they have been taught the art by a good master. Practical experi- ence will enable any man to become a proficient in pruning and training, who may remain his whole life in ignorance of the motion of the fluids, or of the manner of the changes which take place in the tree he prunes. But every practical man will do well to study and make himself acquainted with the physiology of plants ; it will enable him to trace many effects which occur in his practice to their real causes, and free his mind from all doubt as to the practicability or impracticability of whatever he may wish, or find it necessary to do. If we except the failure of the lowest branches of trees, there are few indications in nature showing the necessity of pruning. In natural forests trees gene- PRUNING. 223 rally grow closely together; of course their lower branches, being deprived of air and light, quickly perish ; but when by accident they stand singly, the lower branches are as pe/manent as those of the top, and even more so, and moreover appear to be as necessary a part of the system. When, however, trees are taken under the care of man they are sub- jected to controul, and are trained to answer the purposes for which they are cultivated, whether that be for the timber they supply, the shelter and orna- ment they afford, or for the fruit or flowers which they yield. For these different objects trees undergo various manipulations of the pruner, and which may be separately considered. Forest-tree Pruning. Forest trees are regarded either as objects of ornament or of profit; sometimes used as screens, for shelter, or for fences. Ornamental trees require no assistance from the pruner. Natural forms cannot be improved by art or by the most refined taste. It is only in woodlands, raised and maintained as sources of profit or income, that the skill and exertions of the forest pruner are available. Here the special object is to obtain the greatest quantity of marketable timber. With this view he endeavours to prune his trees so as to form stately, straight, and clean-grained boles, standing as closely together as will allow every tree a sufficient share of air and light. This disposition as to interdistances, and the desired form of bole, can only be obtained by giving attention to the trees in the early stages of 224 PRUNING. their growth. To have timber of the finest grain and quality, no lateral branches should be allowed to arrive at any considerable size, that grow within the conve- nient reach of the primer. They act as rivals to the principal stem ; and if after they are seen to act thus injuriously, they be cut off, the wound thereby made is so large that a flaw in the timber is the consequence. The soundness of timber is not deteriorated by pruning, provided the wound made in lopping- be no greater than will be covered by new bark and wood during the following- summer. A scar made by the axe, bill, or chisel, if exposed longer than twelve months, will always be a defect in the timber ; for though it may be afterwards covered smoothly over by the new collapsing wood, it is impossible that any perfect union can take place between a surface of timber exposed to the air for six months, and that which is subsequently formed over it. Forest pruning is generally performed in the winter ; all wood work (except oak, larch, c., felling- and peeling) is done in that season, chiefly because the leaves are off, and the growth at rest. It is necessary to state, however, that lopping performed in the beginning- of summer would be a better prac- tice for the good of the trees. The reason is this ; wounds made in winter do not immediately begin to be healed by the collapsing wood, which in time will be spread over them ; because that member of the system which is alone capable of closing a wound is then torpid, and the exposed wood of the wound is PRUNING. 225 unprotected for several months ; whereas if wounds be made when the vital member or envelope is every day extending itself they are sooner closed, and if not very large, completely covered before the growth ceases in autumn, or, at any rate, early in the fol- lowing summer. It should be a rule with the pruner never to make a wound that cannot be closed in the course of twelve months ; but he can only attend to this rule by a timely application of the knife or chisel. A hand-saw should never be used in pruning forest trees, because if the irregular branch be so large as to require this tool, it had far better be left where it is. Very tall and handsome boles may be formed by the assistance of long ladders, hand-saws, and jack-planes ; but though these large and carefully polished wounds will be in a few years covered with healthy bark and wood, the internal scar will ever remain a flaw in the timber. (Fig. 53.) These cir- cumstances show at once the absolute necessity of pruning at an early age of the tree, for though all Fig. 53. Section of a stem of sixteen years' growth, to show the effect of pruning off a large hranch in the tenth year. Q 226 PRUNING. have a specific character of growth, with a more or less branched head, which they naturally assume when at liberty so to do, they submit to the direction of skill, and many trees of bush-headed character may be trained into a light and aspiring shape, with a well-proportioned length of bole. To take care that every tree has a principal leader is a material object of early management, and to maintain its superiority in the future growth, a chief point to be attended to. All laterals that show a rivalry so as to divide or deform the axis or main trunk, should be displaced; and before they attain such a size as to endanger its soundness by removal. Very small branches or spray need not be removed from the stem ; whether they live or die they cannot deteriorate the timber. Forest-tree pruning may be continued till the plants are twenty years old or more, after that time the trouble and expense of the business makes it inexpedient ; but if they have been judiciously pruned up to that age, sufficiently fme forms will have been given, and proper length of stem secured. A great deal has been said relative to the propriety of lopping trees as a means of increasing the size of the bole. The question lies in a nut-shell : the larger the head be, the greater must the trunk be also : the diameter of the latter is formed by the number of branches which are or have been produced by the former. In proportion as the roots increase, in like proportion are the stem and head extended. Severe mutilation of the head paralyses the energy PRUNING. 227 of the roots, and vice versa. Reducing the number of branches to give magnitude to the stem is ridicu- lous. Regulating the growth of the branches by stopping or cutting out such as are over luxuriant gives supremacy and a direction to the leader ; but this gives no magnitude to the trunk. Every indi- vidual twig of the head is a part of the stem ; the former could not be developed without assistance from the latter, which, while it conveys support, is increased in some degree to enable it to do so. In fact, every member of a tree depends on, and in its turn lends assistance to, every other, when all are in perfect health. The only exception to this as a rule is an accidental luxuriance, sometimes exhibited by a single branch and a certain division of the root, which will progress together for several years before the rest of the tree. (Fig. 54.) For such irregularity, however, no good reason can be assigned. Fiff. 54. 228 PRUNING. The foregoing remarks are applicable to deciduous trees only ; and with respect to them the forester has only to bestow the necessary attention for a few years to give the desired form while they are within convenient reach ; if the vigour be properly directed in their youth they will seldom fail to grow up hand- some and valuable timber trees. As a rule, every branch which shows a rivalry to the leader should be displaced by the knife or turn- ing-saw, close to the stem, as soon as it has attained a diameter of one inch ; such a wound will be quickly healed, and without risk of injury to the timber. As the different kinds of forest trees are used for various purposes, the forester endeavours to supply the various demands. It is wrong that any advantage derivable from woodlands should be left to chance. Some tradesmen require the straightest and clearest grained oak for planking, beams, posts, &c. Besides this, in the dock yards, cross-grained butts and knee timbers are in request, and consequently valuable. The former description of oak, as well as that of all other trees, is obtained in the shortest time by a rather close order of planting, and early and careful prunings and thinnings if requisite ; the latter by open planting and partial pruning; that is, not by aiming at a tall smooth bole, but by leaving the branches in sets, as it may happen, of three or four diverging from one place, and clearing the stem of all intermediate branches and spray between the sets. This style of pruning, though it has never perhaps been executed, is, never- theless, quite practicable ; it is only pruning the oak PRUNING. 229 to resemble the disposition of the branches of a fir tree, only with greater distances between the tiers. Fir timber for the use of builders and mast makers cannot be too free from knots, and it is impossible to have it so, unless planted and trained up in the closest order. When so disposed no lower branches can live to distort the longitudinal structure of the bole. The centres of the trunks when cut up for use, only show the bases of the first laterals ; but every concentric layer of wood imposed after these first branches decay is free from knots. (Fig. 55.) Fig. 55. u y Vertical section of a tree, the lateral branches of which had con- secutively died, or been cut when three years old. A single fir requires a large space, and produces the worst timber ; its first branches continue to en- large and extend themselves, sweeping the ground as long as the stem continues to rise ; and though the latter arrives at a great size, its timber is of the most inferior description, being deteriorated by large knots. (Fig-. 56.) 230 PRUNING. Fig. 56. Section of a fir tree which has never been pruned, supposed to he cut through opposite branches. In fact, fine grained deal cannot be produced unless the trees are planted, or chance to stand so closely together as to prevent all extension of branches. All sorts of the pine tribe intended for profit should be planted to grow up, and, like a field of corn, be all cut down together. Such plantations do not admit of being gradually drawn, except when very young. They may be called, on this account, social trees ; for as soon as the unity of the congregation is broken, the exposed trees, for want of their wonted protection, not only cease to thrive, but many die. Firs planted for ornament should stand at forty or fifty feet dis- tances ; otherwise they cannot show the grandeur of their forms. The pruner must not touch them ; his interference only tends to make them the most ugly objects in the vegetable kingdom. Planted as nurses in young woods of deciduous trees, they are kept PRUNING. 231 within due bounds by a very simple method of pruning recommended by Mr. Billington, viz. by pinching off from time to time the leading buds of the branches. This induces a spray-covered, rather than a naked stem ; and prevents the encroachment of the branches, without destroying their character as nurses. By the same means, fir trees may be formed into impervious screens, or sheltering hedge-like boundaries ; very useful in many cases of rural improvement. Ash timber is produced of superior quality by being grown in close order ; its toughness and clearness of grain makes it enviable material for the coach maker. Straight, smooth sticks of ash, fifty feet in length, and from eight to twelve inches diameter, are highly prized by all machine makers. Whether for timber or underwood this tree should always be grown in plantations by itself; not only because of its greater rapidity of growth, but because it is a most noxious tree in hedge rows, or as standing single in corn fields or meadows. Oak and elm are best suited for hedge rows. It is incredible how much elm timber can be raised in hedge order. And as the superiors are cut down, a constant succession of young stems are rising from the old roots. No tree bears pruning so well as the elm. So severely is this executed in Middlesex and elsewhere, that a very small branch only is left at the top every time the tree is shredded. This property of being unhurt by wholesale pruning, is owing to the vivency of the tree which, being every where studded 232 PRUNING. with latent buds, throws out a numerous spray over all the stem ; and, though unequal to increase the diameter of the trunk as a large branched head would do in the same time, yet it gives the wood a gnarled character particularly useful for the naves and fellies of carriage wheels, and other purposes where liability to split would be a defect. Ages had elapsed before forest trees were considered as objects worth the expense of pruning ; but during the last century, the great demands made upon both public and private woods and forests, and the great quantities of defective timber rejected at the dock- yards, at last called attention to this neglected branch of rural economy. The defective state of oak timber was attributed to the want of pruning. The rotten stumps of branches which had been torn off by the wind, and which in their decay admitted water into the trunk, were said to be the cause of the disaster. Pruning was therefore had recourse to ; but a bad style was introduced, viz. cutting off the lower branches at the distance of two or three feet from the bole. This plan was soon given up ; not only because it disfigured the tree, but also because many of the stumps dying, the same defects followed this practice as were complained of before it was had recourse to. Close pruning was next recommended ; but with no good result, as has been previously shown. A middle course is now adopted, namely what is ca\\Q& foreshortening. This method preserves all the branches, but the lower ones are kept back, by having their leading shoots repeatedly taken off. (Fig. 57.) PRUNING. Fig. 57. 233 This is particularly suitable for hedge-row timber, as it prevents the trees from overshading the land. It must be observed, however, that though this method gives soundness, it does not produce clearness of grain, which is the grand object of pruning. (Fig. 58.) Fig. 58. Section of a trunk which has been foreshortened, showing that clear grained timber cannot be obtained by this method of pruning. 234 PRUNING. Lopping. In countries where fuel is scarce or dear, hedge-row trees are pollarded and periodically lopped for domestic purposes, and for fencing-stuff. Oak, elm, and ash, are chosen for this barbarous pur- pose. The boles are preserved as the property of the landlord, and the loppings that of the tenant. The trunks soon become hollow, and consequently useless as timber. Willow pollards are extensively planted and maintained in low meadows. The great advan- tage of growing poles, stakes, and headers, for fencing in this manner, is, because they are out of the reach of cattle, requiring no fencing, as a piece of land occupied for the same purpose would do. Willow-holts, for supplying basketmakers' rods, are usually cut every year. In this management it is observable, that every new crop of shoots are per- fected by a new growth of roots. The centre of a willow pollard, and that of a stool soon decay ; and in the rotten mass, roots from the superior buds and shoots are seen to strike and luxuriate. The spec- tacle of a hollow willow-tree being partly filled with roots, which, from time to time have descended from the shoots of the head, gave Dr. Darwin, it is pro- bable, the first idea of the wood of the stem being formed by descending radicles from the buds. But this example of the willow, when duly considered, is no corroboration of the doctor's notion. The shoots of willow, or of any other tree, it is perfectly true, are prolonged by the assistance of radicles simulta- neously produced. The doctor's idea is, that these two members are immediately connected, and that PRUNING. 235 the latter are actually produced by the former, as in the case of a single eye of a vine struck as a cutting ; forgetting, that in the case of a pollard, or any other tree, an intermediate vital member previously exists to form the connection ; and which is constitutionally calculated to allow intercommunication between the moving extremities, without any portion of the shoot descending to the root, or any part of the latter, except juices, ascending to the former. The inter- mediate channel is the vital indusium, containing a compages of sap vessels, which, while they conduct, are themselves enlarged by the impulse and qualities of the rising current *. An argument in support of heading down young and judiciously pruning old deciduous trees, may be drawn from the natural history of many sorts of wil- lows. They are not constituted to be permanent trees. So far from their bulk, number of branches, and quantity of foliage, being incentives to increased vegetative power, an exactly contrary effect is the consequence. As they increase in size the more * This circumstance deserves the notice of those physiologists, who assert that u the matter" (?) which enlarges a stem descends. Because as no upward or other current can he generated unless there be an outlet or reservoir and as the bursting buds, lengthen- ing shoots, and respiring leaves, are these outlets, why may not the sap be deemed capable of enlarging and distending the stem in its ascent, as well as attributing the enlargement solely to it, (or some other matter,) in its descent ? 236 PRUNING. feeble is their growth, till at last all vitality ceases ; whereas were they repeatedly cut in, new powers would be imparted to the system, and by calling forth latent principles of life, continue it for an indefinite length of time. The common furze, ( Ulex Europcea^) requires to be frequently cut, or eaten down to keep it alive. The alder is short-lived, but may be repro- duced successionally for ages. In concluding this section on forest-tree pruning, we may add, that in all cases where large branches, from some accident, require to be cut closely oif, the wound should be covered with some kind of plaster, such as grafting clay, or, what is better, a composition of three parts cow-dung and one part sifted lime. This spread on about half an inch thick, and after- wards dusted with lime to prevent its being washed off by rain, will be found useful, not so much for pre- serving the naked wood, as for accelerating the expan- sion of the vital envelope, which, as has been observed before, extends itself much faster in darkness, than when exposed to light and dry air. Underwood Pruning. Besides timber trees, wood- land consists of underwood also, which is felled periodically. The most profitable trees for this pur- pose are Spanish chestnut, ash, Huntingdon, and other willows ; but oak, alder, birch, and hazel, are also serviceable. Beech and hornbeam are also grown in this way, chiefly for the charcoal manufacturers. But who would think of pruning underwood ? a PRUNING. 237 work never thought of, much less performed. Not- withstanding- this, there is, perhaps, no labour of the forester that would better pay the cost. When a fall has been made, and the stuff all cleared away, the new growth is left to rise as it may. A far greater number of shoots are produced by the stubs or stools than can possibly come to perfection. A major part are underlings, which never rise to be useful for any purpose, being ultimately destroyed by the superior shoots. Hence much redundant, crooked, and irregular growth is produced ; the strength of the stools unnecessarily wasted, and consequently injured. To prevent all this waste and irregularity of growth, the underwood should be gone over at the end of the first or second year after the fall ; all the most promising shoots selected to stand, and regu- lated as to distance and position, and every supernu- merary displaced. At the same time, all useless plants, as briars, ivy, and travellers' ivy, (Clematis,) which rob and encumber the trees and young growth, should be cut down or eradicated. This pruning may be considered a tedious and un- necessary task ; but the very superior stuff obtained by this management, would soon convince a pro- prietor of its great advantages as productive of profit. Fruit-tree Pruning. The different methods pur- sued in the cultivation of our superior fruit-trees, render annual pruning necessary. Artificial forms 238 PRUNING. in forcing houses and frames, on walls and as espaliers, in which the naturally rotund form of the head is dilated on a superficial plane, make the use of the knife indispensable. We not only endeavour to make a tree fruitful, hut must also keep it within the bounds allotted to it. Confined to the artificial position im- posed, the tree is ever endeavouring to regain its natural form by the production of fore-right shoots or breastwood. Part of this is preserved to fill up vacancies, and to keep up a due supply of bearing wood in every part of the tree ; the rest is periodi- cally cut away. In this requisite treatment it is, however, better to direct the growth by displacing irregular or redun- dant shoots on their first appearance, or even while in the state of buds, than to allow many shoots to be produced which must ultimately be cut off. Such manipulation can only be executed on such fruit trees as are so placed as to be under immediate control, viz. all trees in houses, on walls, espaliers, or such other dwarfed forms as may be adopted in the garden or orchard. In this business the manager has to distinguish between the treatment necessary for the encouragement of the general growth of the tree, and that subdued degree of it which is requisite to its fertility, and the reduced volume which its limited situation and artificial form require. If both the root and head be allowed to advance without a suffi- cient check, both will be excited into greater action than is suitable for its limited space, and the knife PRUNING. 239 must be applied to keep it within bounds. But the tree which is only kept within bounds by annual dismemberment, will, like the willow before spoken of, be, like it, prompted into unnecessary luxuriance unsuitable to the purpose for which the tree is cul- tivated. The main point to be aimed at is, as soon as the tree has nearly covered the space designed for it, to keep it in that moderate state, which, while it possesses health and sufficient vigour to produce a crop of fruit, and yield a supply of young wood necessary for succeeding crops, is all that is requisite. By thinning the buds or young shoots early in the spring, excessive growth is repressed, and a qualified expansion of the whole system induced. It is an old saying, " the more you use the knife the more you may." This, however, is spoken of severe winter pruning, which on many trees causes exuberance in the following summer ; but preventing the summer growth by reducing the demand upon the root, has a contrary effect. If every shoot produced by a peach tree, for instance, were suffered to be perfected, a thick irregular mass of brushwood would be the con- sequence ; a corresponding extension of the root takes place at the same time, and which would stimulate still more the growth of the next year, whether this mass of brushwood were pruned off or not. To avoid both extremes is good management; encourage moderate growth by allowing a middling iy*siTs ..** _-*%*,. 240 PRUNING. number of rightly placed shoots to be perfected, but no excess or paucity should appear. This, however, being, as before observed, an arti- ficial state of the tree, the art of pruning (by which is meant both winter and summer thinning) is in no case required to be executed with more precision than in the management of our forced and wall fruit-trees. It has already been said that the manner in which a tree bears its fruit directs the pruner's operations. The fruit buds of peach, nectarine, and some kinds of cherries, are borne on the young moderate sized shoots of the previous year. Of these, in the sum- mer regulation, an abundant supply are selected and preserved by being carefully fastened to the wall or trellis, if so trained. At the winter, or rather spring pruning, the pruner has two special objects in view, first, to secure a full supply of young shoots to enlarge, improve the symmetry, and fill up vacant parts of the tree for the crop of next season ; and, secondly, to keep a sufficient number of bearing shoots to yield the crop of the present. A judicious use of the knife obtains both these objects, and the result shows the necessity as well as the excellence of the art. A good pruner regards the regular form and equal distribution of the bearing wood, rather than an increased number of fruit which, by leaving some promising shoots, might be obtained in any one season. When the tree is getting thin of bearing PRUNING. 241 wood, there may be a few promising shoots thickly beset with flower buds : these, however, would not be preserved for their fruit, but cut down to produce a greater number of young shoots for the service of the next and following years. There is no depending on old branches of peach and nectarine trees for the pro- duction of young shoots, though this does occasion- ally happen ; the lowest placed young wood of the above trees is therefore preserved in order that there may be a constant succession from the bottom. It has been stated that the vital envelope contains the principles of buds as well as of roots, and as some trained trees, particularly peaches and nectarines, are liable to lose their lower branches, it is always desir- able to bring forth young shoots from the naked parts of the stem or branches. This may sometimes be accomplished by art, though the trees here mentioned are the least tractable of any for obtaining such result. The manoeuvre is to cut a notch through the bark, immediately above the place where a shoot is wanted, and removing carefully any dead scabrous bark from the lower side, latent buds may be prompted into action. May is the best month for performing this on stone-fruit trees, and at the time of pruning for others. But the same object is more certainly ob- tained by the insertion of buds, or grafts, at the usual seasons. Here we may observe, that besides a proper thin- ning of shoots, thinning flowers is sometimes expe- dient. Taking off redundant fruit is an every-day 242 PRUNING. practice ; but regulating the number of flowers is not so much practised as it should be. There is an evident connection among- the fructiferous gems, even before their expansion. The whole may require a greater amount of nutrition than the tree is able to supply for their perfect expansion ; but by reducing the number, selecting the best placed and most pro- mising, the residue will certainly come forth with greater vigour, and consequently would more likely set their fruit, as well as be followed by that of increased size. The morella cherry, and several other fruit trees, are lavish of flowers, which must exhaust the tree ; and it is said that thinning them with scissors before they blow well repays the labour. Disbudding trees of their style of bearing, would, however, be an endless task, and indeed unnecessary, as the same object may be gained by a freer use of the pruning knife. Destroying flowers is not a pleasant affair to the anxious manager ; he would be inclined to thin the fruit rather than the flowers; both, however, may be done with advantage, espe- cially in respect of weakly growing trees. Although the manner of bearing defines the plan to be followed by the pruner, yet this may be de- parted from. Those trees that usually bear their fruit on longer or shorter portions of the last year's shoots, as the peach for example, may be pruned in such a manner as to be made to bear on shoots so shortened as to resemble spurs. This mode of pruning may be described in a few words : The tree is trained PRUNING. 243 in the fan manner, and rather in close order: the extremities of the leading shoots are always carefully prolonged, till the space allotted for the tree is occu- pied. Along the branches numerous shoots are annually produced : a proper number of these at due and regular distances are laid in close to the wall between the principal branches, and the rest displaced. At the spring pruning the preferred shoots are loosened from the wall, and cut down to an inch or two in length, and tied to the branch if necessary, leaving the spaces between the branches clear for the reception of the summer shoots to be trained in as before. The curtailed shoots bear the fruit in great numbers, and of fine quality. This plan is called the mother-branch style, by French gardeners, and is highly recommended by an able practitioner * in this country. The grape vine may be similarly managed ; its fruit may be produced on very long or very short last year's shoots, like spurs ; indeed from neither, but from latent buds seated at the nodes of the old stems ; but, strictly speaking, the fruit of the vine is always borne on the shoots of the present year. The long shoot method of training and pruning may be performed in the open air, or in houses ; but it is most commonly practised in pineries, or other houses, where the vines are only trained to each rafter. Each plant has one bearing shoot the whole * Mr. John Seymour. R 2 244 PRUNING. length of the rafter ; this is destined to bear fruit only, no other growth being suffered on it, except the bases of the side shoots bearing the fruit, their points being pinched off immediately beyond, and one succession- shoot trained from the Jowest part of it. When the fruit is all gathered, the whole of the shoot that bore it is cut away, and the young succession shoot takes its place, to be treated in a similar manner in the ensuing year. This method of pruning the vine is exactly like that practised in pruning the raspberry ; the shoots that bear the fruit this year die, and are cut away to make room for the bearing wood of the next. This alternate, or rather successional plan of managing the vine, may be continued for many years ; and if the plant be kept vigorous and well treated, generally with great success. The principal attention required is to cause the lower buds to burst simultaneously with those situated above ; because the vine, like other trees, commences growth at the top, and as this part of the shoot has also the greatest excitement from the higher temperature of the upper part of the house, it will very naturally happen, that the upper buds forming outlets for, and attracting a chief share of, the rising sap, deprive the lower of their due portion ; hence the latter are liable to remain inert. As this is always an unprofitable, as well as an un- sightly defect, cultivators practise various means to effect a general movement of all the buds from top to bottom as nearly at the same time as possible. PRUNING. 245 One of the means employed is by reducing the num- ber of the buds ; that is, at pruning- time, to cut out two-thirds of them. Calling the topmost bud one, cut out two and three, leave number four, cut out rive and six, leaving seven, &c., all the way to the bottom. This disposition of the buds will be found alternating with each other very regularly, as well in position as distances ; and though the number of bunches be reduced, the weight of the crop is not so ; because the buds that remain come forth with increased strength, and yield larger bunches of fruit. Indeed, for a tree trained on such a limited scale, one third of the usual number of buds is as many as the plant should be allowed to bring to perfection *. Even in this method of equalising the development of the buds, the upper ones will precede the lower ; but the former being stopped immediately beyond the fruit, or removed entirely if barren, causes the lower to burst in succession downwards. Another expedient to induce every eye upon a long shoot to burst at the same time, is by bending it into a zig-zag direction, or serpentine position on the * That the strength of fruit-trees is exhaustible by heavy crops is well known ; two very plentiful ones very seldom following each other. No tree, therefore, that is within convenient reach, should be allowed to overweaken itself in any one year, more especially very young trees in houses. The increased size and excellence of a moderate number, which at the same time does not enfeeble the tree, is always preferable to great numbers of inferior size and quality* 246 PRUNING. lower part of the rafter ; this effects a retardation of the upper buds ; by the whole being in nearly an equal temperature, each bud has a more equal share of the vegetative impulse. When all are by these means put in motion, the shoot is then put up in its place. There is another device practised to cause all the buds on a long shoot to burst at the same time, that is, by bringing it down to a horizontal position till all have begun to move ; which, when this is eifected, the shoot is again put upright. This result, like the foregoing, is attributable to the equal temperature in which the shoot is placed, and to the unnatural posi- tion of the shoot. Vines cultivated in pineries never have, in conse- quence of the high temperature constantly main- tained, that degree of hybernation, which, as natives of the temperate zone, they require ; of course they become exhausted by the continued excitement. To obviate this, some pineries are so constructed, as to admit of the vines being shut out of the house during winter, and taken in again at the proper season. When the vine is made to bear its fruit from short shoots or spurs as they are called, the first shoots are treated as has been described of long single shoots ; only instead of this being entirely cut away to be succeeded by a new one, it is left, and no successor is trained up. Instead thereof, the short laterals that have, or should have borne the fruit, are cut back to two eyes, whence the shoots and fruit of next year PRUNING. 247 are produced, and stopped at the joint above the fruit as before : these, in their turn, are cut back in the year following, and again and again, so long as they continue fruitful, and do not overshade too much the interior of the house. When the practical man is employed in thus dress- ing the vine by divesting the tree of all leading and superfluous shoots, for the express purpose of enlarg- ing and perfecting the fruit at the summit of every shoot, he is puzzled to understand that dictum of science which affirms that " the matter " which in- creases the stem and fruit thereon, "descends:" because if this maxim be right, his practice is evidently wrong. So must stripping gooseberry and currant trees of their summer shoots, with a similar view, be injudicious. But in the case of the vine, it is not likely that such management will ever be abandoned. But a remarkable property of the vine is its power of yielding fruit from latent or invisible buds, pro- vided the stern be in a suitable situation for receiving sufficient air, light, and heat. In a former part of this volume it has been assumed, that terminal flower buds require periods of one, two, or many years to perfect themselves before expansion. Here we have an instance of latent buds issuing from the nodes of the old stems without exposure to either air or light, save what they receive through the vascular struc- ture of the stem itself. This, however, is, it appears, sufficient for the preparatory maturation of the fruc- tiferous parts of the vine. The difference in the con- 248 PRUNING. stitutional arrangement may, perhaps, account for the dissimilarity between the pear tree and the vine. The flowers of the former are terminal ; those of the latter, lateral. The first have the common pedicle seated on the pith, the last on a lateral prolongation of the wood, which, if unfertile, resolves itself, as before observed, into a tendril, In this hand-smooth style of pruning the vine many more shoots are produced than it would be prudent to leave ; a few only at each joint are chosen, and the supernumeraries displaced. It is always in the power of the pruner either to have a few and large fruit, or a greater number of smaller; this is determined by his own special purposes, or by the vigour and capability of the tree *. Of all fruit trees, whether in houses or elsewhere, the vine is the most tractable and easy of manage- ment. Erect in different gradations ; with an upright stem and horizontal branches, or with an erect stem and the branches trained from two top horizontals downwards ; an excellent method for furnishing the naked parts of the garden walls between the dwarf trained trees. In fact vines may be led in any way, and so as their shoots have sufficient air and light, with the necessary summer care, always succeed in a suitable temperature. Left to itself the vine is a most disorderly grower ; the shoots are furnished with both tendrils and lateral * It is right to observe, however, that this method of treating the vine is rarely practised. PRUNING. 249 shoots, which require constant removal in house or wall management. The tendrils are a useless ap- pendage if the vine dresser does his duty. The lateral or water shoots' 3 *' are somehow connected with the organisation of the principal huds ; because if they be trimmed off from the leading shoot when it is growing strongly, the bud at their base will very frequently burst, and consequently be lost for the service of the following year. To prevent this, the laterals are stopped above their first joint, which will hinder unnecessary exhaustion of the tree, and at the same time not injure the principal buds, on the preservation of which the crop of the next year entirely depends. At the pruning season these laterals, if any be left, are cut closely off. Here it may again be necessary to repeat, that the summer dressing is to check the natural luxuriance of the tree, confine the sap in the desired channels, and give a full supply of this to the crop of fruit. Vine dressing is even extended to regulating and thinning the bunches, in order that the berries may swell to a full size, and be not injured by bearing too closely on each other. Connected with the management of the vine may be mentioned a method of planting it practised in some parts of France, and which deserves to be noticed. It * It is said that some kinds of the grape vine in the south of France produce second'crops ; the last from the laterals of the prin- cipal shoots. This circumstance occasionally occurs in our hot-houses where the trees are very luxuriant. But neither is such fruit, nor such property of the tree, worth the notice of British cultivators. 250 PRUNING. is well known, that to have short jointed and well ripened wood, high temperature and abundance of air and light are everywhere indispensably necessary; and we find by experience, that to have perfectly mature and high flavoured fruit, the roots should have an extensive horizontal range, and be under some influence of air and the heat of the sun. To obtain these advantages some French gardeners, in- stead of planting the trees close to the wall, as is the common practice, place the root at the distance of six or eight feet, the stem or stems being laid along towards the wall a few inches beneath the surface, and then brought up and trained thereto. This position enlarges the system of roots near the surface, and enables them to yield increased supplies not of watery, but of well aerolated sap. (Fig. 59.) Fig. 59. Vine borders in this country have been formed on a plan somewhat similar, with a view to obtaining the PRUNING. 251 assistance of the sun's heat and full air for the roots ; and with the greatest success. This is done hy lay- ing a bed of gravel, if no such thing exist naturally, twenty inches from the surface, on which a vine com- post is laid about fourteen inches thick, and over this the gravel, to form a walk of good width in front of the vinery. Fruit trees which bear their fruit chiefly on the shoots of last year's production, are pruned so as to allow of being trained in the fan manner ; and though the spur-bearing trees may and are also trained in the same Way, yet as low espaliers, or on low walls, they are most commonly trained horizontally, i. e. with the stem erect, whence lateral branches are led in opposite pairs. Trees so trained have a neat sym- metrical appearance, and may be continued to a great distance on each side. The only drawback on this style is, that the greater part of the tree on each side of the stem is generally barren. This is caused by the trainer's dislike to long irregular spurs projecting from the horizontals, which destroy the snug regu- larity of the tree, to maintain which the knife is used at least twice in the year. Thus the strength of the tree is chiefly wasted in the production of numerous shoots, destined by this style of pruning and training to be cut away. That this fashion of sacrificing the use of the tree to its artificial beauty is a very prevalent horticul- tural error, must be granted ; but that both objects may be gained is not an impossible case ; for it has 252 PRUNING. been proved by an eminent horticulturist * that the summer shoots may be so managed as to be formed into fruit-bearing- spurs all over the tree. This system of pruning is chiefly applicable to the more choice sorts of trained apple and pear trees ; and is de- tailed at great length in the Gardener's Magazine, vol. iii. p. 1, and in a treatise on the subject by the same experienced practitioner. The principle is, by stopping and shortening at different* times a selected number of the summer shoots, the buds at their bases are prompted to become flower buds on every part of the tree. Here we may again observe that the idea of a bud of a pear or apple tree requiring two or more years to raise it from the state of a leaf bud, to that of a flower bud, appears to be reasonable in the case to which we have just alluded. That there are excep- tions to this as an invariable rule, has already been shown ; but here it holds good in respect of those buds left at the base of the shortened shoots which, in a longer or shorter time, become fertile. It has been presumed in our view of the structure of apple and pear trees in particular, that every bud contains an embryo flower on the summit of its axis, and that it only requires a certain exposure to full air and light, and a certain stationary repose, to mature its reproductive organisation. To illustrate this process of the development of a bud of a tree we * Mr. Charles Harrison. PRUNING. 253 have already compared it to the bulb of a seedling- tulip. The senior division of the latter, from the moment it assumes the form of a bulb is composed of a certain number of leaves which, in the space of a few years, are annually expanded, and the centrally placed flower at last comes forth ; so the former is first a leaf bud, and under favouring circumstances is ultimately a flower bud. If in its first stage it receive extraordinary excitement from the exuberant state of the tree, and before its fructiferous principle has had time to become mature, it is ejected forth as a summer shoot with the incipient flower on its apex ; but if, from its lateral position or other cause, it be arrested in its place, and expand only a few leaves in the first year, and a few more in the second, it is very probable that a bud so developing itself will be a perfect flower bud in the' third year. The result of the method of pruning above adverted to, pretty clearly shows that the foregoing description of the progress of a leaf-bud to a flower-bud is sufficiently proved. The different methods of pruning trained trees, adverted to above, are applicable to most of the common sorts, the fig except ed. This fruit tree, in its native climate, yields two crops every year, and upon two sets of shoots. The first shoots are produced in the spring, and ripen their fruit in the autumn. A second birth of shoots comes forth about Midsummer and perfects their fruit early in the following summer. But in this climate, although the tree grows in the same manner, yet the fruit on the spring shoots never 254 TRAINING. ripen in the open air, and the crop on the Midsummer shoots not till the autumn of the following year. The British gardener, therefore, must preserve the Midsummer shoots, and to assist their formation may stop the spring shoots in June in order to procure a full supply of young wood after that time. This tree, when skilfully managed, well repays the labour bestowed on it. It may be kept and forced in pots, and trained in any direction. It bears ringing and every kind of manipulation with impunity. As severe pruning has been shown to predispose a fruit tree to produce barren growth rather than fruitfulness, it is necessary to be cautious in the use of the knife, when the object is the production of fruit. The grand desideratum is, after a tree has arrived at a fruit-bearing size, so to manage it as to induce moderate growth. As this cannot be accom- plished by pruning, cultivators have had recourse to other expedients, viz. different modes of Training. It has already been observed, that the growth of trees is always most rapid in right lines, whether these be perpendicular, oblique, or horizon- tal from the root. The fluids progress with increased celerity in direct channels ; consequently when the stem or branches are bent into tortuous or circuitous positions, a steadier flow is generated, and subdued action takes place promotive of fruitfulness. Besides the different methods of training already alluded to, gardeners have invented several very curious and successful modes, which are worthy of imitation. TRAINING. 255 Dwarfs and riders, the former to cover the lower, and the latter the upper part of the wall, are com- monly planted. Both are trained in the fan manner ; but this form is not indispensable to peaches, necta- rines, &c., any more than to other kinds of fruit trees, for they may be led in any direction, and often with manifest advantage. Low walls may be covered by half riders, merely by training- one half of the branches downwards, and the other upwards ; that is, allowing the branches to diverge in all directions from the top of the stem. For pear trees and the like, French gardeners adopt the method called a buisson, i, e. like a bush. This is formed by driving a row of stakes in a circle round, and at about eighteen inches distance from the stem of a young tree. The branches are brought to the outside of the stakes, and trained spirally round them in one direction, Fig. 60. Fig. 60. 256 TRAINING. The advantages of this style are, the branches are allowed to run to a considerable length they are supported against injury from wind the whole tree is within easy reach, and occupies but little space on the borders of a garden. Another plan is called (I quenouille^ i. e. like a dis- taff. In this the stem is trained erect, and the branches drooping ; spreading to a diameter of four or five feet at the bottom, and tapering upwards into the form of a cone. Fig. 61, A rank of trees trained in this manner have a very dressy appearance, and as the branches do not over- shade each other, is an advantage which the preceding has not : both are equally convenient and suitable for dwarf fruit-trees. The object of this training is merely to counteract the aspiring and spreading tendencies of the trees, TRAINING. 25> and by so doing inducing moderate growth and fruit- fulness. It has been said of orchard fruit, particularly the apple, that they have only a temporary period of health and fruitfulness, and that after the meridian of their vigour and fertility, they become constitu- tionally so feeble, that they cannot be perpetuated by any method of propagation without conveying the decrepitude of the old to the young trees. As all kinds, forest as well as fruit-trees, die of old age, it is perfectly reasonable to conclude, that any one of the latter, which are but varieties, and have endured the operation of grafting, pruning, and other manipulations, should be necessarily shorter lived than a natural tree of the forest ; and also that their decay will commence sooner than such as rise from seed. That grafts and buds carry along with them certain characteristics of the parent tree has been already shown : it is a fact of which there can be no doubt ; and if such old apple trees produce no perfectly sound young shoots, it cannot be expected that healthy young trees can be reared from them. But, on the other hand, if the young shoots at the top of the old tree be perfectly sound, and free from visible decay, they are as well fitted to be the basis of a new tree as any other shoot produced at any former period of the parent's life. It must be admitted, however, that during these last thirty or forty years, there has been real difficulty 258 TRAINING. in raising healthy trees of some of the old, esteemed sorts of apples. Whether this difficulty has arisen from a careless choice of grafts, or from the assumed cause above alluded to, we are not quite satisfied, because the failures have not been universal ; and because we know, that if a young golden pippin, for instance, be planted in an old orchard or garden, it seldom thrives ; whereas, if planted in fresh, newly trenched soil, it both grows and bears well. It is also well known, that though a great majority of the old golden pippin, golden rennet, and nonpareil trees have gone to decay in old orchards, there are in many places fine healthy trees of all ages growing vigorously ; so that much of this failure of orchard- fruit may have proceeded from local or accidental causes. An apple-tree, like all others, has a natural term of life. It stands till the interior of the trunk is dead and rotten, and then falls a prey to the wind : not- withstanding that the vitality on its exterior, though weakened, may be as essentially perfect as ever. It appears that the amiable Evelyn did much in his time towards advising the planting of orchards, as well as forests ; and it is probable, that the orchards planted about that era, (1700,) are those which of late years have so suddenly gone to decay. Planting and maintaining orchards has been al- ways considered as a legitimate object in rural eco- nomy ; and more or less attended to, according as the usage or taste of the rural population in articles of AND PRUNING. 259 diet, rendered orchard fruit necessary. In Hereford, and other western counties of England, orcharding- is an important concern, because cider and perry are the common beverage of the people. This was also the case in most of the middle and eastern counties formerly ; but in these, extensive orchards are gone to decay through sheer neglect, owing to the substi- tution of porter and other malt liquors instead of cider, and consequently making the cultivation of barley upon light land, (unfit for grazing purposes,) much more profitable than a crop of apples or pears. Added to this, the introduction of tea instead of milk diet among the lower orders, has not a little tended to discourage orcharding, (which were also pastures for milch cows,) and cause the neglect of those fruit- trees, which used to be depended on for the drink of the farmer and his family, and which are now said to be wearing out. To the foregoing observations on pruning and training fruit-trees, a general remark may be added, viz. : as there are hardly two situations exactly alike in all things, the same rules will not always be applicable. Soil, aspect, climate, and particular varie- ties of fruit will require particular and local modes of management ; and that practitioner, who has the most comprehensive views of the physiology of trees and their culture, and who can divest himself of old rules, (considered by too many as indispensable,) will have the best chance of succeeding in his practice. He will not be cramped by precedents, though recom- s2 260 SHRUB PRUNING. mended by the first masters, nor confined by fixed rules in any of his operations ; but considering only the local circumstances which affect the objects of his care, will shape his manner of both pruning and train- ing accordingly. The practice and opinions of intel- ligent practitioners alluded to in this section, are not so much brought forward for dictating rules, as to show the tractability of the physical members and evolutions of plants. Flowering Shrub Pruning. The object of the fruit-grower, and that of the florist, in pruning their respective plants, is nearly similar. The florist endeavours to gain either numbers, or magnitude of flowers. All sorts of trees and shrubs having terminal flowers, as Magnolia, Camellia, Rhododendron, c., are made floriferous, by checking luxuriance of growth, which is accomplished by the means practised for dwarfing fruit-trees, viz., by grafting, budding, con- fining in small pots, limiting the supplies of water, or lowering the quality of the soil in which they are grown. Such as bear their flowers laterally, as the almond, myrtle, &c., should, by pruning, be made to produce numerous shoots, in order to have a full bloom. In general, however, our flowering shrubs, as well as trees, are left to nature ; little pruning being necessary except to keep them in form. Of all flowering plants roses require most knife- work. It is indispensable to correct their straggling habit of growth, as well as to obtain perfect and abundant bloom. The flowers being borne on shoots SHRUB PRUNING. 261 of the present year, which, when the flowering is over, remain of very irregular lengths, require to be annu- ally cut back to the second or third bud at their base, which buds yield the flowers of the next year. Tree roses are a lately introduced ornament of our shrubberies and lawns. The high estimation in which the rose is held, is always an excuse for the natural deformity of the tree ; and the new form imposed, viz., a tuft of flowers and foliage on a tall, slender stem, supported by a stake, is any thing but graceful, unless they stand among evergreen shrubs. In this situation they are very striking, and when worked with different sorts, which flower at different seasons, very orna- mental. Such should be always closely pruned in, not only to keep the head more compact, but to in- crease the number of the blossoms. The flowering season of roses may be retarded or prolonged, either by late transplanting in the spring, or by double pruning, that is, when the shoots, after the first pruning, are about an inch long, to prune them off down to the next undeveloped bud below* Gard. Mag. The florist extends his pruning even to his her- baceous plants. The principal flowers of pinks, car- nations, georginas, chrysanthemums, &c., are much enlarged by being divested of supernumerary stems, or of the secondary flower buds on the same stem. This leads to remark here, that thinning flowers or fruit, operating so as to cause increased bulk of those that are left, shows that the current of nutri- 262 PRUNING. tion from the root may be diverted into any number of channels that skill may direct, either for the pur- pose of enlarging leaves, shoots, flowers, or fruit. Table fruit-bearing herbs, as the melon and cucum- ber, require pruning ; their fruit is borne on the tertiary, much more frequently than on the secondary or primary shoots ; therefore the two latter are stopped at the proper time to cause the production of the former. The manipulation is, however, always governed by the state of the plants ; those raised from old or mrch dried seed, often show fruit on the secondaries ; thereby rendering the production of tertiary branchlets the less necessary. 263 CROSS IMPREGNATION. ONE of the most important advantages which has arisen from the discovery of the sexes of plants, is the practicability of improving both flowers and fruit by what is called cross impregnation. f By this means we find that plants are susceptible or partaking of each other's forms, colours, and qualities, thereby allowing the combination of excellencies obtainable in no other way. When we contemplate what has been accomplished in the amelioration of our native fruits, or consider how much our culinary vegetables have been improved, we can attribute these beneficial results to nothing else than this susceptibility of vegetables receiving sexual impressions from each other. In former times and before the study of plants had become a science, many improvements had taken place by accident. The improved sort, whether a new variety of a flower or fruit, had a conspicuous station in the collection of the orchardist or in the bed of the florist. Its qualities were imperceptibly distributed around among its congeners by no other agent than the unconscious bee flitting from flower to flower, or by the less certain instrumentality of 264 CROSS IMPREGNATION. the passing breeze. In time, however, botanical physiologists, investigating the powers and principles of vegetation, and seeing that the male matter or pollen of plants was a deciduous and transferable body, conceived the idea of obtaining by manipulation, what had before been only adventitiously accomplished by the bee and the breeze. Conveying the male to the female plants of the Linnean class Dicecia, and the male to the female flowers of the class Monoscia is an old practice ; but that of transferring the pollen of hermaphrodite flowers from one to another is a modern invention. Whoever was the first practitioner of this ingenious art is not, perhaps, exactly known ; but every body in the horticultural world is aware of the valuable results which have followed the judicious experiments of A. T. Knight, Esq. president of the Horticultural Society of London. That gentleman, by the skilful transference of the pollen of one fruit tree to another, has produced some excellent sub-varieties of fruits which are estimable acquisitions to the dessert. His example and writings on the subject, have extended the powers and practice of the florist as well as the fruit grower ; valuable consequences have already taken place ; and a boundless field is opened to the cultivator for farther improvement in every branch of gardening. The impregnation of the ovulae of one plant by the pollen of another, is a phenomenon which cannot be illustrated in any other way than by comparing it CROSS IMPREGNATION. 265 with similar phenomena happening- in the animal kingdom. In the latter it is only nearly allied species which hybridise. The mule and hinno are hybridal varieties of the horse and ass ; but of this there are but few exactly similar examples among plants. Among- the latter, family affinities only can be affected by the pollen of each other. Attempts have been made to show that many of our species are only amalgamations of others ; and that all intermediate species between the first and the last of a genus, are only adventitious creations ; yea more, that the varied vegetable king-dom originated from a few Fuel that first sprung up in the waters, and after- wards spread over the face of the earth. But this view is wholly visionary ; being applicable to varieties of plants only, not to species. Animal hybrids have a peculiar characteristic, viz. that though the progeny from the cross partake of the form and muscular powers of both sire and dam, they, with very few exceptions, are denied the power of reproduction. Real hybrids have been raised between two species of Verbdscum many years ago by Mr. Haworth, and lately between two species of Digitalis by professor Henslow and Mr. Denson. The hybrids of Digitalis were barren, and in this resembled those of animals, but among varieties of species, some of which, from the monstrous fulness of the flower, are indeed sterile, yet in general they are prolific, and consequently capable not only of perpetuating themselves, but of being multiplied into 266 CROSS IMPREGNATION. sub-varieties without end. It is amongst this last description of plants that the art of cross impregna- tion promises to be so useful an auxiliary in the business of the fruit and kitchen gardener. The manoeuvre generally succeeds under the following circumstances: the two plants whose pro- perties are sought to be combined, must be nearly allied varieties of the same family or genus, as apples with apples ; cherries with cherries ; roses with roses; pinks with pinks, &c. There must be a verisimili- tude of structure ; and of the qualities of the juices respectively. The pollen must be perfectly ripe when used, and the stigma to which it is carried must also be in its fully mature state. In order that the impreg- nation may take place and be complete, it is the custom of some florists to deprive the flower operated on of its own stamina, to shade and shelter it if necessary, and by displacing rival flowers near it, give every chance and encouragement to the impregnated flower to ripen its seeds. If a new and valuable variety' of fruit be thus obtained, we must admit that the change originates in, and is conveyed by, the impregnated seed. Hence a question arises, will the seeds of this improved variety continue the improvement, or do they after the first generation go back to their originals ? This question has not yet, perhaps, received an answer from experience ; but if answered negatively, then we conclude that it is not only like other improved fruit trees in this respect, but also, that it is the impreg- CROSS IMPREGNATION. 267 nated seeds only that convey the change. In advert- ing to this circumstance in another place we have supposed that the floral and other members of a plant may be changed or improved without the seed itself being affected. But in the case we are now consider- ing, it is evident that some of the seeds are affected by the strange pollen, because the seedlings raised therefrom present the improvement. On this subject we need more information ; for it is not easily under- stood why varieties of herbs, as cauliflowers for in- stance, as before observed, should perpetuate them- selves by seeds, and not those of fruit trees, as the apple and the orange. The practicability of cross-impregnation has alarmed scientific botanists ; they fear that their classifications will be thereby broken down into a chaos of non- description, in which all specific and even generic distinction will in time be so amalgamated that iden- tification will be impossible ! Without partaking of these fears it is but right, however, to declare, that as it can serve no purpose of the mere botanist, the practice of impregnation should be confined entirely to the business of the commercial and amateur florist, the kitchen gardener, and more especially the fruit- grower. When we look at the varieties of the Hyacmthus orientalis and the Tulipa gesneriana ; or when we consider (what is of much more solid advantage to mankind) the improvement of the austere crab and sloe, the worthless gooseberry and strawberry in their 268 CROSS IMPREGNATION. native woods, and, moreover, the wild cabbage on our shores, we must admit the great importance of cross impregnation, as one of the means which has brought about such signal triumphs of cultivation as are exemplified in the improved varieties of these several plants. But, besides these, we may instance the beautiful varieties of cherries from the wild guigne ; the peach and nectarine, probably from the almond ; and, in warmer climates, the almost count- less numbers of the citron family, from the unculti- vated lime. What has been already accomplished is invaluable, and is an earnest of how much more may be done by similar means. Among onr cultivated fruits many are regarded for peculiar qualities of high flavour, long keeping, or as abundant bearers. These properties of one variety may be transferred to others where they are wanting. A good bearer of inferior quality may be improved by being dusted with the pollen of a high flavoured sort. The union of a ribstone pippin with a hawthorndean, for instance, would be an improvement. That between the whiteheart and bigaroon cherries would be a desirable variety; and so of many others. Among flowers, the prospect opened by the prac- tice of cross-impregnation between varieties is bound- less ! Where splendid colours are required to be added to elegant forms ; where variegation would improve a one-tinted blossom, or where the rich colours of a dwarf are sought to be given to a flower of more ample habit, all this is in the power of the CROSS IMPREGNATION. 269 skilful hybridiser. All bulbous stemmed, and other herbaceous flowering plants, as well as shrubs and trees, are susceptible of such mutations. Even the ingenious farmer, who may be acquainted with this transmutable property of plants, may benefit himself and his country by creating new varieties of corn. Our best known kind of barley for the pur- pose of malting, indeed for all purposes, is only a variety, and, what is more, a deformed and imperfect sort, inasmuch as two sides of the spike are always abortive ; yet this is preferred to all others. Among the varieties of wheat, some have short ears, but with superior grain as to quality ; others with very long spikes of inferior grain. A union of these is fairly within the bounds of possibility ; indeed it is more than probable that superior varieties of all our corn may be obtained by cross-impregnation judiciously executed. But enough has been said to direct atten- tion to this curious subject, it being unnecessary to point to particulars, which will readily occur to every one engaged in, or the least acquainted with, the cul- tivation of plants. There is a circumstance connected with manual impregnation which may just be mentioned; it has been observed that strange pollen, that is, such as is taken from other congenial trees, is more effectual in its operation to secure the production of seed than that of the plant itself. The filbert and cob-nut are said to bear more profusely if assisted by having a branch of the common hazel, well furnished with 270 CROSS IMPREGNATION. catkins, suspended over the former trees at the proper season. Whether this effect, supposing it true, be owing to the proper male flowers being expended too soon, or from the incontinent appetite of the females, is uncertain. Be this as it may, the phe- nomenon is, however, very similar to what is often seen to take place among breeding animals. Another advantage arises from cross-impregnation, namely, making fine flowering exotics that are too tender to bear the open air in Britain, more hardy. If the tender female be dusted with the pollen of a hardy male of the same genus, or vice versa, a variety will be produced which will possess the beauty of the one in a great degree, and the hardihood of the other ; and by advancing to gain hardiness in one direction, fine colour may be obtained by trying back. If acclimatation be at all a practicable expedient, cross-impregnation appears, from what has already been accomplished, to be one of the most effectual means. This opinion is founded on what has lately been accomplished in crossing the Rhododendrum arbbreum with the JR. ponticum ; an intermediate variety has been obtained, partaking of the colours of each somewhat blended, together with a great portion of the hardiness of the R. ponticum. As species have only a limited range of constitutional variation, we know not how far such changes may be carried ; but even this union between two reputed and distinct species shows that our knowledge of the powers of plants is not yet complete. 271 VEGETABLE FOOD. WHAT is the food of plants ? has always been an interesting- question among cultivators. The che- mical philosopher says ascertain by careful analysis the qualities of their components, and you may safely infer that similar bodies or qualities must necessarily be their food. This doctrine, however, notwithstanding- its plau- sibility, has not been fully proved by experience. Vegetables are so organised that they are not only capable of imbibing various fluids from the earth and air, but also can assimilate them to their own essen- tial qualities. From the same situation and soil, different plants extract different principles. The Saccharum qfficinalis and the Janipha manihot grow on the same spot ; the first elaborates the most agreeable and nutritious juice ; the second a most dangerous poison ! But, perhaps, the philosopher only alludes to the elements of plants, such as oxygen, hydrogen and carbon, and not to their elaborated qualities. If so, it may be observed, that all these exist universally in the air and water, consequently more or less in 272 VEGETABLE FOOD. every kind of soil ; so that were it possible to collect them in such a shape as to be tangible and distri- butable the attempt would be superfluous ; except only as regards carbon, which, as it exists in the excrement of animals, is a powerful assistant to vegetation wherever obtained and used. But by far the greater part of our knowledge rela- tive to the food of plants, has been derived from experience. Chemistry, with all its powers of ana- lysation, c., has hitherto done but little, and that little seldom attended to as it deserves, especially in the management of farm and stable yard dung, and composition of mixings or composts. Every culti- vator is aware that all recent or decomposed vegetable matter is a useful pabulum of living plants ; as well as all animal substances whether recent or rotten. Farm-yard, fold, and stable dung, wood ashes, bone dust, and horn shavings ; the refuse and sweepings of butchers', curriers', and fellmongers' yards and workshops ; linseed and rape seed cake ; woollen, linen, silk, and cotton rags: in short the offal of every employment, where either animal or vegetable substances are manufactured are all found valuable manures. Mineral substances, as salt, lime, chalk, marl, coal, culm, soot, and ashes, are all used on land as direct or indirect stimulants thereto. These combined with some of the components of the staple, promote it is said the solution of effete matter, and prepare it for the sustentation of plants. VEGETABLE FOOD. 273 When the texture or constitution of the soil re- quires amelioration, other expedients are had recourse to besides adding- to its fertility. The best soils are composed of nearly equal portions of sand and clay, together with the detritus of calcareous rocks, and decayed vegetable or alluvial matter, generally called loam. Its consistence is friable ; readily admitting air and rain, and as readily discharging all excess of the latter only retaining, or imbibing from the air, as much as is suitable to vegetation : and neither liable to be parched in summer, nor drenched with surface water in winter. If a cultivator be situated on a soil which is dif- ferent from the above, his main endeavour is to improve, by bringing his land as near to this standard as he has means or opportunity to accomplish. Covering his sand with clay or marl, or his clay with sand, is the most direct, though a most expensive mode, and which but few can undertake except on a small scale ; yet when these two descriptions of soil lie contiguous, the union may be performed gradually, and a garden or a farm may be completed in no great length of time. Such improvement of the staple of land, with perio- dical dressings of good manure, would amend and render it capable of bearing any kind of crop; and moreover facilitate all operations necessary to be performed upon it ever after. Lime is much used as a quickener of the soil, and for the purpose of banishing insects, and particularly '274 VEGETABLE FOOD. the slug. Both lime and chalk are excellent appli- cations on clayey soil for counteracting its adhesive- ness ; because, as both are powerful absorbents of water, the frost acts with redoubled force in disrupting the compact surface of the clay rendering ploughing and harrowing easy. Both these substances, as well as common salt, are also used on dry gravelly land ; they being attractive of moisture in all seasons, and consequently highly serviceable to summer crops. It is only when lime is in its caustic state it is preju- dicial to slugs ; after being slaked and saturated with moisture it only acts in the manner of chalk. Some kinds of lime-stone contain magnesia; which last substance has been found deleterious to vegetation in its caustic state : and therefore only fit to be used on peaty soils. All fresh or newly broken up ground contains some peculiar quality particularly acceptable to plants, especially such as have never, or not for a long period before, been cultivated thereon. Such soil is called maiden or untried ; and unless decidedly sterile, by reason of wanting a sufficient depth of surface mould, or strongly impregnated with metallic principles, will yield abundant crops successively for several years. From this circumstance it would appear not only that vegetable food exists in soils which have never been enriched by the cultivator, but that it is also exhaustible. Hence the necessity of applying manure to keep land in heart, and to enable it to yield remunerating crops. VEGETABLE FOOD. 275 Maiden earth has not been investigated by the chemist so thoroughly as it should be. They have attended more to the analysis of what are supposed to be manures, than to those qualities of natural soils which are so eminently salubrious to vegetation. We are still ignorant whether this quality be a chemical or physical body ; or whether some latent principle set at liberty or brought into action by the plough or spade. Certain it is, however, that the first crops on newly broken up land are always superior to those that follow, and when a garden soil becomes " worn out/' as it is called, it can only be renewed by removing the old, and replacing it with an equal quantity of fresh earth from a common or old pasture. As a mixture or change of plants on the same spot arrive at greater perfection than if one sort only were sown by itself, or repeatedly sown or planted on the same place, it has been reasonably supposed, that different plants require different kinds of food*. On this supposition the system of what is called " convertible husbandry" and the different courses of cropping adopted by agriculturists are founded ; and the uniform success attending such procedure is sufficient proof of its propriety. Hence the value, and necessity of composts being formed of every kind * It is believed by some botanists that every plant has the power of disgorging matters which are hurtful to the system, by which the soil becomes unfit for others of the same kind. T 2 276 VEGETABLE FOOD. of vegetable and animal matter that can be collected and incorporated together, in order that the crop, whatever it may be, may have the power of selection. The luxuriance or weight of a crop is always in proportion to the richness of the soil, or to the quan- tity of manure bestowed, other circumstances being favourable ; but it is usually apportioned to the nature of the crop intended to be raised. If bulk of stem, leaves, or roots, is the object, it is scarcely possible to give too much ; but if for superior grain or fruit, moderate quantities answer best. In whatever way manure be applied, whether by incorporating it with the soil, or diluted in water, the effect on the plant is the same ; every part, viz. root, stem, leaves, flower, and fruit, are enlarged, showing that either the vegetative vigour receives extraordinary excitement, or that the juices become more copious, so that their power of distension is in- creased. Stronger and accelerated growth is the eifect, and no doubt caused by the additional supplies of aqueous and gaseous elemental bodies essential to the plant which are afforded by the manure ; but whether these supplies be carbon only, or a combination of various chemical principles collected by the spongioles, and so imbibed together, we have yet to learn. One thing is very certain, that all substances used as ma- nure, are more or less effectual according as they are more or less attractive, and retentive of humidity. Respecting the effects of fallowing, it is quite evi- VEGETABLE FOOD. 277 dent from experience, that it is only necessary and useful for two purposes. The first is the destruction of weeds, the second the amelioration of the soil. After a course of four or five crops, which have been only partially, or not at all weeded, root- weeds, par- ticularly quitch, thistles, docks, and several others, get possession of the soil, and render it impossible to extirpate them without a summer fallow. On the other hand, if land be of a strong, clayey, adhesive nature, fallowing is absolutely necessary to prepare it for the reception of seed. As to the idea that land is benefited by exposure to the sun and air, except for the purposes of desiccation and more perfect com- minution, no greater error was ever conceived ; be- cause it is well known, that the nutritive qualities of the soil are fugitive under the action of the sun and air. Laying light land into ridges, either by the plough or spade, to receive a winter's frost, is, there- fore, not only a waste of labour, but of some of the best principles of the soil. Deep trenching, digging, or ploughing, is beneficial to trees and all plants of robust character, not only because it allows a greater range for the roots, but also because it permits the ascent of warm and humid vapours from the bowels of the earth. When the staple of land is once well broken up for corn, deep ploughing is not so necessary afterwards. The effects of different soils on the quality of vegetable productions may just be noticed. Fruit or vegetables raised on a light sandy loam, having a 278 VEGETABLE FOOD. gravelly subsoil, are always found of better quality than such as are produced on rich heavy land. That is, the fruit, though smaller, contains more sugar ; and the kitchen vegetables, though more diminutive in bulk, are of better flavour. The concentrated juices in both these cases, and farina of cereal plants, are greatly superior to the productions from off deep, rich, or highly manured land. Grossly exuberant crops are always more crude in the quality of their sap, as well as coarse in cellular structure. These circumstances should not be forgotten in forming fruit borders ; mistakes are often committed in making them too rich, as well as too deep ; hence the trees grow too luxuriantly, and yield large- sized fruit ; but the flavour is inferior. Fresh unexhausted loam, pro- vided it be dry enough, is the best for all kinds of fruit-trees ; and this last particular can only be ensured by efficient drainage. 279 DISEASES OF VEGETABLES. THAT plants are subject to disease is generally admitted, though it is often difficult to distinguish constitutional distempers from the attack of insects or of parasitical plants. The canker, mildew, uredo, smut, ergot, are all prevalent ; and all other disorders, whatever may be their cause or origin, are compre- hended under the common name Blight. Canker appears to be really a constitutional dis- ease. It is a dismemberment and corruption of the organisation, occasioned, it is supposed, by unwhole- some aliment, taken up by the root from ferruginous soils, and which, when lodged in the tender vessels of the young shoots, undergoes some chemical change destructive of the vital envelope and all the other members of the plant. It first shows itself in small blisters on the epi- dermis of the young shoots, or round the buds, and at the base of the spurs on the older branches. The taint quickly spreads, corroding every organ in its course. The parts affected become suberous, fractured and monstrous, and are chosen as a nidus by several species of insects, whose larvae feeding on the lips of 280 DISEASES OF VEGETABLES. the sore, prevent the efforts of nature to heal it up, till at last the branch on which it appears is destroyed. Partial attacks are sometimes cured by cutting away the diseased parts and applying plasters of grafting wax, or of cow-dung, clay, and urine. That the taint of canker spreads from its first visible station, is very apparent to the operator when cutting out the infected part. The principal sap vessels are tinged with a brown unhealthy colour for a considerable distance from the first seat of the dis- ease ; all which contaminated organs must be cut away before a cure can be effected. Canker is more frequently seen on orchard fruit trees than on others. Among forest trees the ash and elm suffer most. It is invariably found, that the most luxuriant growing trees are more subject to the attack than such as are of moderate growth ; and those on dry sound situations, less liable than such as stand in wet soils where the drainage is imperfect. Low sheltered situations, where there is not a free and constant ventilation, also appear to invite this disease. This being the history of the distemper, it is quite obvious that no topical application can be effectual as a cure. If the poison be taken in by the root, from pernicious qualities in the soil, or if generated by unwholesome air, these circumstances must be changed before the attack of canker can be averted. Shallow planting, perfect drainage, and the application DISEASES OF VEGETABLES. 281 of proper manures to neutralise the injurious qualities predominant in the soil, are the most eligible means to be followed to preserve trees from its ravages. Canker also appears on some sorts of herbs. Blanched celery, endive, and lettuce, are all subject to be disfigured and spoiled by something like canker. The curl on the leaves and the scabs on the tubers of the potato, are deemed to be diseases of the same kind. So is that on the cucumber and melon ; but on these last the cause is well known, namely, a want of sufficient heat in conjunction with too much humi- dity. Some of the former may be the work of invi- sible insects 9 fungi 9 &c., and others, as the brown spots on celery and the curl on potatoes, appear to be ende- mial, as they are only known in certain districts for a year or two, and then disappear. Our reason for averring this much is founded on the history of the disease, and on what we have gleaned from experi- ence. At one time the curl was very prevalent in the south of England, now it is rarely and only par- tially seen. Some writers attribute the disease to the use of over ripe tubers as sets. Many cultivators in the Lowlands of Scotland prefer potatoes for sets, grown on cold moor earthy districts in the Highlands. In Wales it is said to be an insect ; but in most of the central counties of England, as it is seldom seen, no precautions are taken to prevent it, except occa- sionally changing the kind, or procuring sets from a distant place ; and this not to prevent curl, but to obtain better crops. From many published reports 282 DISEASES OF VEGETABLES. it would appear that the defect exists in the eye before its sprouting, because how else can we account for one eye only (the one nearest the umbilical cord) being generally, if any at all are, curled, and no other. Whether it be an insect or a disease we have still to learn. In all these cases we find the cellular organisation imperfect and decomposed, and soon afterwards the resort of insects or the seat of fungi. There can be no doubt but that canker is sometimes caused by the attack of insects, by injudicious pruning, or by acci- dental wounds ; but it is equally certain that it appears spontaneously, as if generated by some deleterious quality received either from the soil or situation. It is more than probable that canker is transfer- able from one tree to another by intergrafting; we very often see maiden plants attacked by it before they are removed from the nursery ; and though this is generally attributed to the presence of an insect, it is as likely to have been introduced on the graft. There is a fungus known among naturalists called ^Ecidium laceratum, which fixes itself on the bark of the whitethorn and pear trees, occasioning canker- ous spots, and consequently pernicious to the plants. It is, however, endemial, and often mistaken for canker. Mildew infests many kinds of plants and assumes many different appearances. On peach and nectarine trees, it seizes the tender points of the shoots, which it quickly destroys. On the leaves of the apricot, DISEASES OF VEGETABLES. 283 cucumber, &c., it shows itself in spots, and in dry seasons it is almost always seen on the leaves of early turnips, and late sown peas in the autumn. It has been ascertained by naturalists that mildew is a species of fungus which attaches itself to certain plants when they are in a peculiar state of growth favourable to its nature. If this be so, it cannot with propriety be called a disease, though its effects are equally destruc- tive. Luckily it is a vegetable parasite of a more delicate constitution than are the plants it fixes on, because it very soon yields to an application or two of a strong soap lather or a lixivium of flour of brim- stone and water. By these means it is easily banished from trees in houses, or on walls. And there is no doubt but that water slightly impregnated with soda, or any alkaline salt, used as a wash, would defend plants from its attack, as well as recover those already suffering from it. Its appearance on turnips, and particularly on peas, is said to be a consequence of drought ; and that if the latter crop be well watered when necessary, the mildew is prevented. Uredo or rust. This is a malady, or rather an injury, to which cereal plants, wheat in particular, are often liable. This, like the mildew, is also a fungus, which seizes on the leaves and straw in such numbers as to interrupt the course, or withdraw the whole current of the sap. Hence the grain is imperfectly filled, the colour and tenacity of the straw is destroyed, and the crop, of course, generally deteriorated. Rust first appears on the leaves of strong growing 284 DISEASES OF VEGETABLES. plants of wheat early in May, but it is not seen to fix injuriously on the culms till about the 20th of July. Should the weather at this last mentioned date be dry, and at a high temperature, no ill effects from rust take place ; but should wet weather then set in, chilling- the air, and checking- the exhalations from the ground, immediately the straw is struck, and sud- denly changes from a bright yellow to a dingy hue, a certain sign that the blight, as it is commonly called, has seized the crop. About this time the grain is just arriving at perfection ; if the attack takes place before this is effected, it never fills ; if afterwards, less damage is sustained ; the straw may be injured but not the grain. In looking over a blighted field of wheat we observe that the lowest and richest stations, or where the crop is thin on the ground, receive the pestilence more severely than the higher situated, or poor portions of the field. In some seasons the crop is only partially, or locally affected ; in others not a culm escapes. These circumstances prove that the evil is always commensurate with the susceptibility of the plant to receive it, and to that critical state of the atmosphere which favours the vegetation of the fungi. Some writers have imagined the Pucinia graminis (the name now given to this fungus by botanists) is the effect, not the cause of the malady. The evil, say they, proceeds from exuberant growth, and a sur- charged state of the sap vessels, which first rupture the cuticle, whence the sap flows out, forming an DISEASES OF VEGETABLES. 285 attractive and suitable seed-bed for the fungi ; and, therefore, advise the farmer to dress his ground moderately to save his crop. Were the diminutive or stunted plants never assailed by the rust, then the above opinion may have some weight, and the advice some value ; but in a blighting year, every wheat plant, from the smallest to the largest, suffers ; showing- that it is an atmospheric influence that predisposes the plants to suffer, and the fungus to luxuriate. The propagines or seeds of the fungus are impalpable and invisible ; and being carried by the w r ind from place to place, settle on every object, but come to perfection only on such plants as are in a suitable condition to receive them. The same species of fungus* or one nearly allied to it, is frequently seen on the common berberry, coltsfoot, and some other plants. Hence old fashioned farmers eradicate the berberry from their hedges. A laugh has been raised at this practice, but there is more propriety in it than superficial observers are disposed to allow. As the ovse float in the air there are no means of averting the attack. Early and thick sowing on sound and well drained ground, is the only practicable preventive. Smut. This is a disease peculiar to cereal plants. * It lias been lately ascertained by J. Rennie, Esq. professor of natural history in King's College, London, that the parasite fungus on wheat is a distinct species, and not the same as that which attacks the berberry and some other plants. This is confirmed by recent discoveries of other naturalists. 286 DISEASES OF VEGETABLES. Its history is obscure ; it not being ascertained whether it be the work of an insect or the seizure of a parasite. The husk of the grain, instead of con- taining healthy farina, is filled with a black stinking powder, rendering the grain unfit for the baker, and often unsaleable. It is not a radical distemper, else all culms and ears from the same seed would be equally affected, which is seldom the case ; plants, and even the same ears, are only partially smutted, which would not happen did the defect originate in the root. The disease exhibits itself in two ways; in one, the husk bursts and the black powder is mostly dispersed by the wind and rain ; in the other the husk remains entire, is cut, carried, and threshed with the bulk, and from which it cannot be separated except by washing in water to float the smut-balls. In this latter state it is dreaded by the farmer, as its presence greatly deteriorates the value of the crop. As a prevention against smut, farmers endeavour to banish it by brining and liming the seed. This is partly, though not entirely, effectual ; but how it operates is unknown. Those who imagine the evil to be a fungus, say the pickling frees the seed from infection ; while others, deeming it an insect, believe the ovse to be destroyed by the salt and quick lime. Ergot. This is a disease of the same nature as smut. It is prevalent in rye, and is a great drawback on its value, in places on the continent where this grain is cultivated for bread-corn. Farmers in the south of France attribute its prevalence to a certain DISEASES OF VEGETABLES. 287 moist state of the air at seed-time. An acute observer in this country thinks it is sometimes occasioned by late frosts, which occasionally affect the plants so as to cause this malformation of the grain. The general opinion is, however, that it is really a fungus, which, seating itself within the husk, changes the meal into grey powder. Several others of the Graminece are subject to ergot. The Lblium perenne, Festuca hordeiformis, and Elymus maritima, are frequently seen disfigured by it ; on the Lblium it is black, and on the Etymus, red. Constriction of the Bark. This is a defect in the growth of trees, occasioned by the diminished powers of the root, or from the desiccating effects of dry or cold air on the branches. It has been already observed, that the bark is an excrementitious part of the plant. Nature intends, that as a new bark is every year formed next the wood, the outer or first formed layers should either be gradually thrown off, as in Platanus, stretched horizontally, as in the beech, or rifted longi- tudinally, as in the oak, to make room for the new accretion within. If, however, from any cause the outer bark becomes unnaturally indiirated, so as to lose its expansive property, the internal growth is confined, and all the functions of the tree are para- lised. Hence it remains stationary, the prey of insects, moss, lichen, and rarely fruitful ; in which state it is said to be hidebound. The old remedy for this defect was scoring the stem and branches from top to bottom quite through 288 DISEASES OF VEGETABLES. the bark with the point of a pruning knife, in two or three places. This, if performed about Midsum- mer, evidently relieves the tree, as its future growth is much increased. The result is perfectly natural ; if the envelope has its expansive action cramped, it will every summer struggle for a vent ; and when the constricting bark is separated, the envelope will im- mediately be increased in volume, and a new impetus given to the secretions of the tree. To such length has this remedy been applied, that the whole outer bark has been, by some 'arboricul- turists, removed, to the manifest advantage of the tree. Indeed the same practitioners maintain, that the general barrenness and failure of old apple and pear orchards, is chiefly to be attributed to constric- tion of the bark ; and the only way to renovate these, or other old trees, is to strip them of their old hardened covering *. It is said that cork-trees are invigorated by the loss of their bark, and that the same trees are stripped periodically without detriment to their health or natural magnitude. Attending to the rationale of this practice, it is true, as has been before shown, that only a few of the recently formed layers of inner bark are absolutely necessary to the vital processes of the system. All those on the exterior are dead, and may be removed * It should be observed here, that if fruit-trees be sound at the heart, and stunted or stationary in growth, they may be assisted by disbarking ; but it is impossible to renovate old hollow trees much by such means. DISEASES OF VEGETABLES. 289 without injury. If the whole bark be intended for defence of the stem only, and on this account pre- served, it appears to be superfluous, because the young- shoots, the most delicate parts of the tree, have only one bark, and this we see is a sufficient protection to all hardy trees ; therefore all the layers are not neces- sary, as is proved by the remedy above mentioned being- effectual. It is the opinion of some practical men, that the chief energy or vital vigour resides in the head rather than in the root of a tree, i. e., the head receives from the atmosphere a maturing influ- ence which alone qualifies, while it excites supplies from the earth. The roots, if in good soil, however old, never fail ; and, therefore, they say, if the head be kept healthy, the system flourishes. To do this, they recommend every feeble or dead shoot to be cut off, and every layer of the old scabrous bark to be periodically removed; so that every latent principle of the growth be called into action, and the progressive expansion of the tree encouraged. This doctrine, with some qualification, we think, is not injudicious. Pear, apple, and other fruit-trees, are the proper objects for this treatment. Such as have a watery, being fitter for the operation than those having a gummy or resinous sap. 290 INSECTS DESTRUCTIVE TO PLANTS. ALTHOUGH it be impossible to particularise every species of insect which breed and prey on plants, a few of the more common and noxious may be men- tioned, in order to show how the health of plants is injured, and their members distorted or destroyed by their depredations. Coccus. This tribe of insects, of which the highly- prized cochineal of commerce is the type, are found infesting plants in hot- houses, as well as several of our most useful fruit-trees cultivated in the open air. The migratory white one, frequently seen on pine- apple plants, is highly injurious by withdrawing the juices and disfiguring the leaves, and still more when they fix themselves on the bottom of the stem among the roots. Both sexes are very minute when young ; but the females, after impregnation, grow to nearly a line in length, are then very sluggish, and probably die soon after they have produced their young. The next species is the well-known brown scale, so frequently seen on orange myrtle, and other plants, whose leaves are of a firm texture. In early life they are wanderers and invisible to the naked eye ; but like the preceding, the females, after impregnation, DESTRUCTIVE INSECTS. 291 become stationary and large, by forming a shield over tbeir bodies, under which they bring forth and rear their numerous progeny. It has been questioned, whether the scale, from under which the young ones come forth, be or be not a part of the body of the mother. If raised from the leaf by the point of a knife, there appear to be six legs, or tentacula spread out, three on each side, of a whitish colour, partly attached to the shell, and also to the leaf; but may not this covering be formed of an exudation from their bodies, by which their young are pro- tected? Another but much larger scale coccus is occasion- ally found in hot-houses, on peach trees, and vines. This is, perhaps, what is called the vine-fretter. Their economy is like the last, only with this difference, that as their young increase in size, the lower edge of the shield is raised up, and the progeny are suspended in a white silky web as large as a middling pea, from which they issue forth when able to provide for themselves. Besides these cocci common in gardens, two others are found in woods and hedges, one of which, coccus arborea, has lately found its way into gardens, seating itself on pear and apple trees, which it weakens con- siderably. In underwoods they attach themselves to the bark of red willow and ash-poles, closely congre- gated together on the lower part of the stems. One of these has oval, the other kidney-shaped scales, or dorsal shields, about two -thirds of a line in length. u2 292 DESTRUCTIVE INSECTS. Their injury to these forest-trees is, however, imper- ceptible. But the most destructive coccus in this country is what is called the American blight, or mealy aphis. This is the great pest of our apple orchards, and to the same kind of trees in nurseries. The young are so exceedingly minute, that they can, apparently, enter the pores of the epidermis, cause a swelling of the cuticle, w^ich soon after bursts. The insects then may be seen in the openings, covered with a white efflorescence ejected from their bodies, intended it would seem, either for the purpose of concealment, or as a protection, instead of the scales with which their less destructive congeners are provided. As this species seems to prey on the juices which flow between the bark and wood, or on the tender substance of the envelope itself, the former year's wood becomes denuded, and the lacerated edges of the wound become corky and monstrous, increasing in size till it encircles the branch, when all communi- cation with the roots is cut off; of course the branch, or if the insects have seized the stem, the whole head, dies. Their manner of living and breeding is similar to that of the others mentioned above ; the females at- tain the size of linseed nearly, and are constantly enve- loped in the white covering peculiar to them, and by the buoyancy of which, it is said, they are wafted from tree to tree. They fix on the roots as well as on the branches of trees, and thus out of sight are often extensively injurious. The male is said to be a small black fly. The blood of these insects, if such it may DESTRUCTIVE INSECTS. 293 be called, is always of a deep, lurid red, showing their affinity to the cochineal insect, indigenous to the Opuntia cochinilifera in South America. It has been stated that this coccus is the sole cause of the disease called canker; but this is a mistake, because cankered trees, both those of the orchard and forest, are every where seen unaccom- panied by this or any similar insect. It is very true, however, that the dismemberment an/?, distortions of the bark caused by either constitutional or accidental canker, are very likely to attract insects to nestle in, and this coccus as well as others ; but the effects of constitutional canker may always be distinguished from those occasioned by the insect in question. It has also been said that the American blight was introduced about 1788 from France by the late Cap- tain S. Swinton, R. N., who had a foreign nursery at that time, behind No. 6, Sloane Street, Chelsea. But however, true this may be, there is no doubt the same insect was in England long before that period ; as old crab trees standing in woods and hedges in the middle counties were then, as now, covered with it. An insect of the same family is frequently seen on the underground stems of lettuce, endive, and dandelion. Of all these insects, the mealy one infesting pines, and the last described so pernicious in orchards, are the most destructive ; they both prey on the vitals of the plant, and their introduction among such as are clean should be carefully guarded against. The first are killed or banished by a wash composed of the 294 DESTRUCTIVE INSECTS. following 1 ingredients, viz. ; " 2 Ibs. soft soap, 2 Ibs. flour of sulphur, 1 Ib. leaf tobacco, 2 oz. nux vomica, and 1 quart train-oil all boiled together in 8 gallons of water. Pine plants require to be anointed all over with the liquor, and when re-potted in fresh soil and in awell cleansed house, are freed from thepest." NicoL The same wash may be effectual for destroying the American blight, provided all the scabrous bark of the tree be first cut away, and particularly the little nodes raised by the insects, so that the liquor may penetrate into every crevice where the insects are secreted. A wash of the consistence of paint, of clay and water, soft soap and quick lime, mixed together applied with a brush is also beneficial to rid trees of this or any other insects. Aphides. This is one of the most numerous tribes of insects which infest plants. There are several species of them, as the ulmi, sambuci, tilia, &c. ; but it is probable, that the same species assume diiferent colours according to the qualities of the juices on which they live. The green aphis on the rose tree, the black one on the field bean, and the red one on the common tansy, are, perhaps, the same insect. They have many provincial names ; as shrimps, blacks, lice, colliers, &c., the most common being the " green fly." Being produced by animalcular generation, their fecundity is astonishing. On trees they blister and deform the foliage, disfiguring it by the emission of what is called honey-dew, so attractive to bees and DESTRUCTIVE INSECTS. 295 other insects. If they are favoured by dry and fine weather about the end of June they will seize the tender tops of field peas in such numbers, that the crop vanishes before them as if scorched by fire ; and when the podless straw is cleared off, the ground is literally covered with their dead and dying remains, together with the sloughs they throw off during their short life. For such visitations there is no remedy ; but in gardens whether they breed on plants in or out of doors, they are quickly dispersed by the smoke of tobacco. Cynips or Gallfly. These insects may be noticed not so much for the damage they do the plants on which they breed, as for the curious transformations produced on the members of the plant charged with their ova. If we examine the large imbricated galls on the extremities of the shoots of the oak, or the large and small globular galls called oak-apples, on the under side of the leaves, we cannot but admire the instinctive sagacity of the parent fly, and the curious expansion of the cuticle, the enlargement of the parenchymous integument under it, and the persisting functions of the sap vessels to supply a monstrous dilatation of all the parts immediately surrounding the inserted egg. As this soon becomes a maggot, daily advancing in size, so is the gall in bulk till the chrysalis is formed; soon after which, the last transformation takes place ; the perfect insect eats its way through its parenchymous cradle, and launches into the open air. The perfect rotundity 296 DESTRUCTIVE INSECTS. of these galls and the pulpy consistence of their sub- stance, in which the astringent quality and colouring property of the tree are notably concentrated, are interesting circumstances ; showing that the uncon- scious nymph not only obstructs the direct current of the sap, but seems from its operations on the interior of the cavity to give form and consistence to the exterior, altogether different from the other expansive processes of the plant. From this incidental pro- duction, the physiologist may remark the wonderful versatility of the cellular body when disposed as parenchyma, and of its other structure in the shape of hybernacula when affected by the insertion of an egg of the Cynips quercus-gemmce. This insect, it appears, has the power of introducing its ovipositor into the very centre of the bud; there the egg obstructs the elongation of the axis, throwing all the growth into the hybernacula and incipient leaves, both of which become unnaturally incrassated, and form a monstrous imbricated bud round the larva while it undergoes the different changes of its youth. The small tubercles on the leaves of the Glechbma are caused by a species of these insects. Haltiaca oleracea. The turnip-fly or beetle is a most injurious insect, as well in gardens as in fields. Every species and variety of the Brassica family are preyed on by this fly, and in some seasons occasion great loss of time and labour to the farmer. They first appear in gardens, early in the spring, on radish, cabbage,- cauliflower, &c, feeding chiefly on the semi- DESTRUCTIVE INSECTS. 297 nal leaves which, if they destroy, occasions the loss of the plant. They attack the turnip plant as soon as it appears above ground, and it is astonishing- how soon a field of ten or twelve acres is eaten off. To this disappointment and loss the farmer must submit, and sometimes thrice in the same season, there being-, as yet, no effectual preventive discovered to defend the crop. The most successful management for pre- serving a crop of field turnips is by sowing drills of the kind intended to stand, rather thinly, alternating with drills of another sort, sowed thickly ; the latter will be preferred by the flies, and devoured while the first grow out of their way: the supernumerary drills, if any of the plants escape, are afterwards hoed up. We know very little of the economy of this insect ; like other beetles it passes the three first stages of its existence in the ground, and comes forth sooner or later in the summer according to the heat thereof, or as the chrysalides are exposed on the surface by the plough ; many farmers being of opinion that the aration necessary for the turnip plant, serves to awaken the sleeping insect, We had been acquainted with this beetle and had suffered much from its ravages many years, without, ever being able to witness its flight ; but one day (20th July last) passing along the Fulham road, and opposite a piece of turnip saved for seed in the nur- sery of Messrs. Harrison and Bristow, we found several of the insects on our dress, and saw thousands sport- ing in the sunbeams over the crop. This circum- 298 DESTRUCTIVE INSECTS. stance shows the fallacy of those arguments in which it is stated, that sowing- ten days after the turnip land is ploughed, or fallowing- two years successively will destroy or banish the insect from the crop. Cecidomya tritici. We are indebted to Messrs. Gorrie* and Shirreff for almost all that is known of this silent working, and generally unnoticed enemy of the farmer. Entomologists had long ago enrolled this insect in their lists, but they were not aware of the destruction it causes to the wheat crop. This small fly generally makes its appearance along with wheat- ears, i. e. about the middle of June. " They seem at first to frequent the vegetable kingdom indiscrimi- nately, but soon congregate in wheat fields, and remain during day on the lower parts of the plants. About sunset the fly becomes active and continues so till sunrise. Possessing a hair-like ovipositor of con- siderable length, the parts of which slide from each other like the tubes of a telescope, by which the eggs are deposited in clusters, visible to the naked eye on the inside of the chaff, commonly when the ear is escaping from the sheath. The maggots, when ushered into life, are very small, and perfectly translucid; they soon increase in size, and become yellow coloured. They seem to subsist in the first instance on the pollen, and latterly on the matter which would have formed the grain. They possess not the power of moving from one cup to another, Of Annat, Perthshire. DESTRUCTIVE INSECTS. 299 and finally leave their birth-place a few days before the plant reaches maturity, and reside in the earth during- winter, a discovery which belongs to Mr. Gorrie." Mr. Shirr eff in Q. J. Agri. The same enlightened agriculturist is of opinion that no effectual check can be given to the depreda- tions of this insect, unless a variety of wheat be obtained whose chaff envelopes the cups so closely as to be impervious to the ovipositor of the insect. This insect is known to exist in all parts of Britain under the name of red-gum ; but its ravages have been par- ticularly severe for several years past in East Lothian where Mr. Shirreff resides, and who calculates that the wheat crop has been damaged to the amount of 30 per cent. Wire-worms. The larva of the elater castcineus is a tough, yellow, smooth, grub, with a brown head, and about three quarters of an inch in length. They are found in all sorts of soil, particularly fresh loam, and in old leys newly broken up. The root of every plant in their way appears to be preyed on by them ; causing great loss to the florist by destroying his bulbs, as well as to the farmer's crops of oats and wheat. There are several other worm-like animals called by this name, one is the larva of a Styphalmus, and the common one, so destructive to onions, is a minute species of Scolopendra. Dressing the land occasionally with lime is the best defence against such enemies, as well as against all the species of Mollusca so hurtful to all young vegetables. 300 DESTRUCTIVE INSECTS. Fingers and toes, or clubbing. This is an attack of an insect called Nedyus contractor. They choose the under-ground stems of almost all the Brassica family as a nidus for their young-, inserting their eggs into the vascular pulp beneath the cuticle, where they are hatched, and pass the maggot stage of their life, during which they subsist on the interior, whilst the bark, as it may be called, is monstrously swelled over the inclosed worm. Their presence and havoc within, derange the organisation, diverting the cur- rent of sap so much as greatly to disfigure and injure, if not totally kill, the plant. Cabbage, turnip, broccoli, and many others of the tribe, are the usual prey of this tiny foe. Dry situations, or soils, seem to be more subject to the visits of the insect than others ; but luckily it has been lately discovered, that any alkaline substance incorporated with the soil defends the plants growing on it from being chosen by the parent fly. Soap boilers' waste is particularly effica- cious for this purpose ; and no doubt all other sub- stances, of similar quality, would be equally serviceable. The Weevil, ( Curculiogranarius^) is destructive to wheat stored in granaries. It is said that if an unwashed fleece of wool be laid near the corn-binn, the weevil will prefer this to the wheat. Other Cur- culioSy in their perfect form, feed on the young shoots of apple trees ; one of the most destructive in nurseries, is about two lines in length, lies hidden in the ground by day at the roots of trees, after sunset they crawl up the stems and eat out the buds, DESTRUCTIVE INSECTS. 301 i especially of new budded or grafted plants, causing- a serious loss to the nurseryman. Being a hardy insect, they cannot be assailed by any nauseous dilution or powder applied to the soil ; but probably something of the kind thrown on the stems and heads by a syringe might protect the buds. Red Acarus or Tick. This is commonly called the red spider. They are a minute apterous insect, though a great plague to the forcing gardener. It infests the leaves of vines, peach-trees, and almost all other plants in the stove or hot-house ; puncturing the cuticle of the leaves and young shoots to extract the sap, and causing its escape, so that the parts lose their vitality and die. This insect is called a spider? because it spins or ejects a web, not for the purpose of entangling flies like the true spiders (Aranea), but for forming a kind of defence against humidity which is most annoying to them. Indeed a moist atmo- sphere, and water frequently and forcibly applied, is a good remedy to banish and prevent their increase. But sometimes they become so numerous in collections of plants to which excessive watering would be preju- dicial, that it is necessary to extirpate them by suffo- cation, which is done by the vapour of flour of brimstone smeared on the hot flues of the house, or from a chafing dish made for the purpose. It has also been found that copious moisture with a very high temperature will expel these insects. There are several other plant ticks, that are comparatively harmless. One sort lives on the leaves of grass, causing 302 DESTRUCTIVE INSECTS. those yellow spots on the sward often visible in autumn. Thrips. Are a very small apterous insect, about one third of a line in length, resembling- an aphis ; having two lateral appendages instead of wings. They gnaw the cuticle of the leaves, and extract the juices in the same way as the red acarus, with which they are often associated in hot houses. They are got rid of by the same means, though with more difficulty than the latter insect. Formica. Ants are sometimes useful, and occa- sionally hurtful to plants. Wherever the aphides are seated, there also are ants busy ; they collect the honey-dew voided by the former, and if there be not a full supply of that substance they take the young insects themselves. In this they are serviceable to gardeners. But in early forced peach-houses, for want of other food, they betake themselves to the blossoms, and eat or gnaw off the filaments, to the manifest injury of the flowers, and consequently of the fruit. Forflcula. Earwigs are well known to be injuri- ous to both flowers and fruit. They, the ant, and the wood louse ( Oniscus) are easily entrapped by placing hollow tubes, baited with sugared water, near their haunts. Gooseberry and Currant Moths. The caterpillars of these insects are particularly destructive to these small fruits. Lime water repeatedly applied, and the ground under the trees dug to bury the fallen cater- DESTRUCTIVE INSECTS. 303 pillars, is one method to destroy them. They may also be driven away by fumigations of sulphur, or other suffocating- effluvia. The foregoing 1 , and many other insects, are found on cultivated plants, which are all more or less inju- rious. To be acquainted with their names, economy, and with the methods of killing or banishing them, is of material consequence ; but as " prevention is better than cure," the whole attention of the cultivator should be directed to this point. It is often seen that plants, subjected to the attack of insects, or of a peculiar injury in one season, are particularly liable to be again affected in the next. It is expedient, therefore, that the application of remedies precede the attack ; if peach and nectarine trees were period- ically washed with a lixivium of soap in the course of the autumn, winter, and spring, it is not probable that mildew would appear on them in summer. And where the visit of the aphides may be expected on trees, the autumn is certainly the season when they would be most effectually repulsed. It is in this season that the eggs of insects are deposited on those plants or substances which yield convenient suste- nance for their young. With this view the careful mothers seek the furrows of the bark, the indentations round the buds and branches, as safe depots for their ova. But did they find these recesses already occu- pied by any quality offensive to them, they would be disgusted, and seek a place elsewhere. The aphides are viviparous in warm weather, and oviparous when 304 DESTRUCTIVE INSECTS, it is under 50 of Fahrenheit. The first broods in the spring- issue from eggs deposited on their favourite trees in the previous autumn ; and from these all the sequential broods of summer proceed. Rose trees require to be particularly well guarded against these autumnal depositions. Other insects besides the aphides choose this plant for their young, the larva of which roll themselves in the leaves, or eat a way into the flower, but which they devour before it is expanded ; in like manner many other fruit and flowering trees are damaged. If then any easily dis- tributable matter, either dry to be applied with a puff, or a liquid discharged by a syringe, were given from time to time in the autumn, there is no doubt of its operation as a defence. In fact it is only making the plants disagreeable arid uninviting to the parent insect, that will save it from the ravages of the off- spring. Salts, particularly alkaline salts, lime, sulphur, or other mineral substances, and all pungent decoctions, are to some one insect or other either offensive or fatal: and many vegetable qualities doubtless there are, which, however innocuous and even nutritious to the human frame, may be highly disgusting to many insects which annoy us. Such are desiderata yet to be discovered by attention and experience . and, in the search, it should be remembered, that the human palate and that of insects are dissimilar ; the aphides riot OH the hop, the elder, and other bitter plants, but which, perhaps, would quickly perish on DESTRUCTIVE INSECTS. 305 some of what we consider vegetable sweets. It has been affirmed that potato water showered on goose- berry and other fruit trees preserves them from caterpillars. Connected with this subject may be mentioned the protection of old ornamental trees, which suffer, or are supposed to suffer, from certain insects which breed in timber. Many stately trees in the gardens of colleges, palaces, and in public malls in cities, have been prematurely killed, it is said, by the larva of the Scolytus destructor. Whether they cause the injury in the first place, or are only attracted by the already decaying members of the tree, is variously under- stood, but the latter circumstance is the most pro- bable*. Trees in public places are liable to many accidents which such as stand in the forest escape. The former are exposed to injuries from the knives of silly people, bruises from the roller, spade, or sithe ; these induce decay ; this invites the insects ; their depredations increase the wounds and prevent recovery. That such accidental bruises may not increase to endanger the life of the tree, the best thing to be done is scooping out all the decayed parts both of bark and wood, and covering the wound with a good coat of tar, in which a little tallow and salt- petre is added, to be renewed, from time to time, if * This has been satisfactorily proved in an excellent paper, by the ingenious Mr. Denson, senior, of Water Beach, near Cam- bridge, author of the " Peasant's Voice." X 306 DESTRUCTIVE INSECTS. exhaled away. This application will prevent rapid decay, offend the insects, and assist the creation of a new bark over the scar. Besides the insects already described as living on the exterior of trees, there are several which are bred in the interior and feed on its living members. The Cerambix gigas inserts her egg in the pith of apple trees, willows, ash, Scotch pine, and even the oak. The maggot eats its way upwards, excavating and subsisting on the material of the pith and wood, leaving behind a hollow passage of not less than one-fourth of an inch in diameter. Before its last transformation it eats a way out of the wood, and reposes in the bark in the pupa state, whence it comes forth a large winged insect. Among sawyers they are called Wurnalls ; and from the size of the trees in which they have been found, and the length of the passage made by them, they must have existed as grubs for several years. How or when the egg is placed in the pith is not known. The damage done to timber after being converted to domestic uses, by boring insects, is too well known to require com- ment. 307 FELLING TIMBER. THIS business of the woodman is usually performed in the winter, on all kinds of trees except oak, and some other kinds, which are not felled till the hark u will run," that is, soon after the bursting of the buds, when the sap is most fluid and in motion. Trees having- a resinous sap may be felled at any time, because it being- less fugitive the timber is less liable to rend in seasoning. Trees are either felled by grubbing or cut over by the saw. The former method may be done in the case of single trees, but in thick standing woods, cutting down with the felling saw is not only the most expe- ditious, but, as the tree may be thrown in any direc- tion, it is the most elegible, no damage being done to the surrounding trees. Grubbing, that is, first baring and cutting all the roots, is sometimes preferred, because it is thought that a little more timber is obtained thereby, and also that the roots, being at once got up, are easier cut from the butt and got rid of, than grubbing them after the tree has fallen. But this is denied by the best woodmen, who assert that a root, while fast in x2 308 FELLING. the ground after the bole is cut off, yields to the action of the beetle and wedges, pickaxe, and dog- iron, much more readily than if lying loose on the surface. Besides, in the attempt to fell a large tree in this way, much time is lost in endeavouring to reach the " tap roots," while the tree is expected every instant to fall. Felling with the saw is therefore the preferable mode, and the manner of doing it is as follows : The workmen first fix where the tree can be most conve- niently thrown ; this is determined by there being a proper opening to receive the head, and without fear of damaging other trees in its fall, and also that the branches of the tree to be felled are so balanced as to number and weight, as not to swing the tree aside while falling to the ground. These circumstances considered, a deep triangular notch is cut at the bottom of the bole ; on the side next to and at right angles to the line along which the tree is intended to be laid. This notch is called " the fall,'* and requires some judgment in forming, because its incli- nation entirely regulates the fall of the tree. The base of the butt is then hewn down perpendicularly all round, the projections of the spurs cut away as low as the horizontal face of the fall, so that a plane is formed on which the saw traverses flatly in its progress through the stem. (Fig. 60.) FELLING. Fig. 60. 309 Manner of felling timber trees, with, the necessary tools. This plane is always formed as close to the ground as possible. The saw is then entered on the side of the tree opposite to the fall ; and as soon as it has passed far enough within the stem, so as to admit a thin wedge, one or two are entered behind the saw, in order that it be not pinched in its play. As the saw proceeds, the wedge or wedges behind receive every now and then a blow of the beetle, in order to keep the tree steady in its place. The saw is worked parallel to the cross cut of the fall ; and is continued towards it, till about an inch only of sound wood remains. The wedges are then beetled till the tree falls ; and this, if the inclination of the fall and the action of the saw have been made to correspond, takes place with admirable exactness. It sometimes hap- pens that, from the unequal distribution or unequal 310 FELLING. length of the branches, the tree threatens to fall out of its course ; this is discovered by one of the wedges going easier than the other, or the saw pinching on one side and not on the other ; in this case the saw must be worked more on the side to which the tree threatens to swing, and thereby giving way first at the final driving of the wedges, allows the tree to fall in the intended place. It also happens sometimes, from unskilful manage- ment, high wind, or unfavourable leaning of the tree, that when the saw is nearly home, and the wedges have not a sufficient bearing, that the tree will sud- denly fall over them ; this is an accident often attended with danger to the workmen, and should be carefully guarded against. When the tree is fallen, all the branches and head are cut off, leaving the measurable timber. The branches, if too small to be measured as timber, are cut into lengths of six or eight feet for billet wood ; the smaller are chopped into three or four feet length for stack wood, and the brush is tied up in fagots about fourteen inches diameter, for the purpose of heating ovens, or burning bricks. These fagots and stackwood, being about the same length, are usually disposed of together ; two pieces of the latter being counted as one fagot. In felling oak, the same steps are taken as above, but with the addition of stripping off the bark from the butt and branches before fagoting, as far up as they are of any size. The bark is first cut through FELLING. 311 across, in lengths of three feet, with the hand-bill, and with its point ripped longitudinally into slips, from six to twelve inches wide. A barking-tool, somewhat like a crutch hand dibber, shod with iron, flattened at the point in the shape of a crescent, the stalk a little bent to follow the rotundity of the tree, is then inserted and pushed under the slips of bark, which fly off with the greatest ease. The bark being thus peeled off, it is afterwards set up to dry. This is done by driving a rank of stakes, (cut from the spray) into the ground about two feet high, having a forked top to receive poles reaching from one to the other. Against this temporary rail, the slips of bark are set up along both sides, pretty closely toge- ther, the rough side outwards ; and along the top some of the widest slips are laid to form a coping. When bark is thus set up, it is sold at so much per yard run. In some places the custom is to disbark the trunks in the spring, and fell the trees in the following winter ; and this with the view of having superior, because winter-felled, timber. That timber felled in winter is less liable to rend in seasoning is well known, and this in consequence of the juices being then coagulated, and almost stagnant ; in which state it is preserved in the timber, and not suddenly exhaled away, as would be the case in summer, when the sap is thin and fugitive. The woodman and carpenter incessantly repeat the traditional maxim of their fore- fathers, that winter-felled timber is more ponderous 312 FELLING. and durable, because in that season " the sap is down." We have already adverted to, and com- mented on, the accuracy of this old notion, and have shown, that, however right the practice of felling timber in winter, the woodman's reason for doing so is not strictly philosophical. But this is of little con- sequence, so as the practical old custom is right. Of the oak we may observe, that disbarking and killing the tree before it is felled, cannot answer any material good. The stem will continue to imbibe water as long as it stands, though deprived of bark ; and as all aqueous sap must be exhaled away before the timber can be used with propriety, little time is gained by this scheme, and no great superiority of quality. It is only the sap wood, or recent layers of alburnum, that suffer by being too quickly seasoned, and this is never, or should never be, used in ma- chinery, ships, or other structure where heart-wood is particularly necessary. With respect to the propriety of disbarking timber in general, we know that in some instances it is right, in others wrong. The peculiar qualities of the tree are often found concentrated in the bark. If these qualities be conservative, persisting, and moreover repulsive to insects, it is wrong to deprive such trees of the bark, when the whole, or parts of the stem or branches are used for any purpose of buildings or fencing : of this description is the larch. On the other hand, if the bark contains no conservative prin- ciple, and be attractive and retentive of moisture FELLING. 313 so as to induce early decay, the sooner it is hewn off the better. While the bark on any fallen tree remains sound, it defends the wood from being- cracked by the sun and air ; but it should not remain after it is rotten, because it forms a harbour for many insects which prey on the wood. Fir and pine timber may be, as before observed, felled at any season ; because the sap being gross and resinous, is less fugitive than that of deciduous trees. It is also to be remarked of pine-trees, that whereas deciduous kinds become decomposed first at the pith, pines are first decayed on the exterior, owing, no doubt, to the internal store of preservative juice. The quality of timber of every kind of tree is always found to be in the greatest perfection when grown on land which is naturally most suitable to them. The most valuable properties uf timber are solidity, ponderosity, toughness, and durability. Ra- pidity of growth gives a coarser grain, and also greater strength of fibre. An oak raised on a sandy or moor- earthy soil, yields timber of a milder texture or grain, than that from off loamy clay ; but it is also less tough, and probably less durable. The durability of oak depends on the strength of the fibrous structure forming the vascular parts of the wood. The fir shows that its cellular members, namely, the exterior side of each year's growth, resist decomposition for a longer period than the intermediate portions of the wood. We have only to look down on an old deal floor to be convinced of this fact, and to an old oak 314 FELLING. gate-post, much grated and worn by wheels, to be satisfied of the other. Felling Underwood. Underwood is felled perio- dically at intervals of five, ten, or more years, according to the superior growth of the stuff, or the purpose for which it is wanted. In value it varies from 51. to lo/. per acre, according to the size or age of the fall. A thriving underwood of mixed, useful, kinds, may be felled every seventh year, and yield a variety of produce, as hop and hurdle poles ; mop, rake, and broom handles ; long rods for crate and basket making ; hoops and headers for fencing ; five feet and four feet stakes for ditto ; withes, pea-sticks, and fagots. The woodman begins by cutting down hand smooth, every shoot, as low and as smoothly off the stubs as possible ; laying the stuff indiscriminately, in large heaps, behind him. This he performs with a stout bill-hook, and a light narrow axe. When he has cleared a sufficient space so that carrying the stuff to the heaps is no longer convenient he next proceeds to trimming. With a light, keen, trimming bill, he takes the first pole, rod, or stake that comes to hand, and having trimmed and cut it to the greatest, or desired length, throws it to the place intended for all of the same description. Thus he proceeds till he has trimmed all that is down ; occa- sionally fagoting up the brush as it accumulates in his way. The next step is tying up the stuff; poles are taled and sold by the hundred, but not tied GRUBBING. 315 up ; rods, hoops, pea-sticks, and four-feet stakes, are bundled in fifties ; withes in hundreds ; mop or broom stakes in sixties ; five feet stakes, &c., in quarter hundreds ; all which bundles are commonly sold at the same price, varying- from eight pence to onft shilling* each. The woodman is paid three half- pence the bundle of common stuff; and two shillings the hundred of poles ; and one shilling- and two pence for fagots. Well planted, and judiciously -managed underwood, is a profitable disposition of land unfit for other pur- poses; and as it yields, or may yield, an annual income, is always an object of interest with the general planter. Grubbing. Taking up the roots of felled trees is one of the tacts of rural economy. Rude and homely as the task appears, it requires no small degree of mechanical power, and judgment in the execution. A good grubber is a person of some eminence in rural society; many spending their whole lives in such labour without acquiring a competent knowledge of the business. An old expert grubber with com- parative ease to himself will earn his three shillings a-day ; while the athletic, young, but inexperienced hand, will be sadly distressed in earning half the money ! A spade, mattock, pickaxe, beetle, dog-iron, a strong lever and rope, and a set of twelve iron wedges weighing from one to five pound each, with a large wooden one, are the grubber's tools. He first 316 GRUBBING. clears away the earth from off the root to the distance of five or six feet from the centre of the stump: cutting through the diverging 1 spurs close to the out- side of the opening. This done, he next considers where he had best insert his wedges ; and here, if he has not an intimate knowledge of the physical struc- ture of the whole root, he will certainly waste much of his time and strength in vain. He should be aware, that to the original axis of the seedling tree, all the exterior accretion has been in the course of time im- posed ; and that the sides of the stump can only be split off in the same order and direction in which they were laid on. His best plan is to endeavour to split the crown into segments, and then reduce each of these segments by taking off slivers from the out- side. But in forming these segments, much judg- ment is necessary. Every species of timber has a natural cleavage ; and this it is that directs the posi- tion of the wedges. Right lines, from the pith of the stem to the centre of each spur or large root, are the proper places for insertion of the wedges. Spurs cannot easily be separated from each other, after they are united in the collet ; because the grain lies hori- zontally from one to the other below. If the division into segments (which is usually done seriatim) be accomplished, the rest of the labour is easy ; as these are reduced by pieces consecutively detached from the outside. Pieces of large size, when split away from the crown, are often held by tap, or downright roots GRUBBING. 317 belonging to them. In these cases, the dog-iron and lever are applied to wrench them off. The dog is a strong hook having a straight shank ten or twelve inches long, with an eye in which a stout ring tra- verses. The lever passes through the ring, and when raised upright its lower end abutting on the base of the root, and the dog fixed above it is pulled down by the rope attached to its upper end. The dog and lever save much labour in doubling wedges and beetling ; and with the assistance of the large wooden wedge, which drops down in the cleft while the lever is worked, greatly facilitates the division of the root. The further duty of the grubber is to level the ground and stack the roots. This last is placing them on a level surface in stacks closely piled toge- ther three feet in width and height, and as long as there are roots to fill up. Every four feet in length is accounted a stack ; and by the number of which the grubber is paid according to the value. The wages being always somewhat less than what the roots will sell for, viz. from four to six shillings per stack. Grubbers prefer taking up roots in the second or third year after the tree is felled ; because the fibres are then all dead and have lost hold of the soil, and then also the root is not so much decayed as to refuse the action of the wedges. A doated, or rotten root, is much more difficult to be split in pieces than one that is sound. Longevity of Trees. It has already been men- 318 LONGEVITY OF TREES. tioned, that all vegetable matter is, during growth and for some time after it is perfected, preserved from decay by the life ; and after this has entirely left, it endures for an uncertain period before its final decom- position by the vicissitudes of weather. The natural death and destruction of a tree happens in conse- quence of the wood, in the greater number of kinds, becoming rotten at the core, which defect continues to increase outwards till the whole axis is perished ; of course the tree is then shattered to pieces by the wind. The age of trees, when no record of their planting has been kept, cannot be ascertained until they are felled ; at which time the concentric layers composing the axis may be seen and numbered; the amount from the pith to the circumference being equal to the age of the tree, or, in the pine tribe, the number of knots from the base to the apex of the tree. This cannot be done accurately unless the whole butt be sound ; because if the tree has stood beyond a certain time, a portion of the centre will be rotten, and then the age can only be guessed at. Nor, even if the age were ascertained, would it be a criterion for judg- ing of the age of other trees of similar magnitude, unless the soil and situation in which they grow be exactly alike. We have histories of remarkably large trees grow- ing in different parts of the world ; as some of the Bombacecz in Africa, the figs of India, the chestnuts of Sicily, the cypresses of Mexico, the pines of Cali- LONGEVITY OF TREES. 319 fornia, the elms and limes of France and Germany, and the oaks of England. The circumferential mea- surement of many of these stupendous plants is immense ; but the greater number are hollow, except perhaps the pines and others having a resinous sap. Many trees of large size which appear sound, are, perhaps, only hollow tubes. The knowledge how long a tree remains sound is yet to be acquired by future generations, as it is but lately that attention has been called to the subject. The general opinion respecting the age of trees seems to be, that when known great age and bulk are united, it is ascribed to the suitableness of the soil and situation. It has been proved, that the best oak timber is produced on loamy clays ; and when a tree is suffered to remain for many years on such a favourable spot, its bulk will be in proportion to its age. But whether, after all, internal decay be re- tarded by the favouring situation, we have yet to learn. A period of three centuries is traditionally given as the age of the oak, viz. the first increasing the second stationary and the last falling to decay : but this is but conjecture ; though it may be safely affirmed, that oak of a century old, having both bulk and quality, is the best for every purpose to which it is convertible. The largest trees in Eng- land are such as have been planted or chanced to stand in church-yards, or near baronial halls ; and which have been spared from age to age as objects of ornament or landmarks, or memorials of eminent 320 CONCLUSION. persons, or remarkable events. But these are of no value as timber ; nor ought the growing, or even the possession of very large trees to be an object of ambi- tion with the mere profitable planter. The strength and durability of oak is said to be always in proportion to the quickness of its growth. But in the case of Scotch, and, perhaps, other pines, the reverse is the consequence. CONCLUSION. IN the foregoing pages, it has been endeavoured to present a plain and concise view of the various structure, functions, and properties of plants. The most ostensible and strongly marked characteristics have only been regarded, because these are what are chiefly required to be known in the business of the cultivator. The writer is well aware, that, by close study and the assistance of a powerful microscope, more correct descriptions and precise representations of the elementary matter, motions of the fluids, and connection of the organisation might be given ; and, moreover, if chemical knowledge were employed in the study of vegetable physiology, many discoveries might be made, which would illustrate the causes of the change of colour, manner of accretion, and some of the diseases to which plants, or parts of plants, are CONCLUSION* 321 subject. But this prosecution of the science must remain for the research of others. Such desiderata will always be an inducement to those engaged in the study or cultivation of plants, to advance physiolo- gical knowledge, and complete the imperfect sketch herein-before given. By attending to the appearances of plants in every stage of their growth, and marking the changes which take place as they pass from one state to another, thereby tracing effects to their causes, is the only way of gaining a complete knowledge of the phenomena of vegetation ; and, when thus attained, every mani- pulation to which plants have been, or may be sub- jected, will be readily and unerringly applied. The principal features of the book will be found to be descriptions of the organs of plants the proper distinctions of stems and roots, which have not been before defined with sufficient accuracy the constitutional structure and development of bulbs and tubers the progressive growth of new wood and bark, and other processes of vegetation, as exemplified in trees and shrubs. A few practical essays are added on the principal operations of the gardener, woodman, and husband- man, showing the application of physiological know- ledge, and serving as proofs of various assertions made in some of the foregoing sections. In arriving at the various conclusions stated in the foregoing pages, besides our own practical tests of many previously published opinions, we have to Y 322 CONCLUSION. acknowledge the great assistance we have derived from the elaborate drawings and descriptions of the stems of dicotyledonous plants, by M.Mirbel ; to those in Dr. A. T. Thomson's Botanical Lectures ; and par- ticularly to the elegant delineations of W. W. Capper, Esq., of Bath, in his lately published descriptions of the Anatomy of the Vine, as corroborative of many of our previously formed notions on the subject. INDEX. A. PAGE PAGE Armature of plants . 156 Abietinse . . 65 Arrhenatherum . 56 Abortive flowers . 172 Arucaria . 95 Acanthaceae . 77 Arum . 39 Acotyledones . 24 Asarinae . 73 Adansonia . . 94 Asclepiadese . 79 Adventitious buds . . 144 Asparagus . . . . 55 jEcidium . 282 Asphodelia . ib. ./Eschynomene . 69 Auricula . 77 Agapanthus . 50 Agropyrus . 96 Alburnum . 109 B. Alder . 67 Alliurn . 50 Bambusa . 95 Aloes . 152 Banksia . 74 Alstraemeria . ib. Banyan fig . 143 Amarantlius . 76 Bark described . 99 Amaryllideae . 45 Bark peeling . 311 Amaryllis . 52 Barrenness, causes of . 168 Amentaceae . 66 of trees . 162 American blight . 292 Begoniaceae . 76 Anana . 167 Betula pendnla . 100 Anariassa . 43 Bignoniaceae . 79 Anemone . 56 Bombax 94, 105 Annual accretion . 140 Bractea . 159 Aphides . 294 Brazil wood . 110 Apocynese . 79 Broadcast sowing . 189 Appendages of a stem . 149 Bryophyllum . 81 Arbutus andrachne . 99 Budding . 217 Areca . 70 Buds, flower . 146 Aristolochia , 73 secondary . 144 324 IND EX. C. PAGE PAGE ^ Cycaa 60 Cambium 109 Cyclamen . 56 Camellia . 260 Cynips 295 Canker . 279 Cytinea 73 Cannabis . . 72 Cannese . 59 Cape of Good Hope . 80 D. Carices . . 38 Carpinus . 67 Darwin, Doctor . . 116 Carya . 68 Daucus 56 Castanea . ib. Decay of ornamental trees 305 Cecidomya . 298 Decorticated tree 138 Cedrus Libani . 66 Denson, Mr. 305 Celosia . 76 Descending effect 129 Cerambix gigas . 306 Development of wheat 178 Cercis . 137 of buds 137 Cereus . 95 Dicotyledones 25 Change of soil . 275 Digitalis 265 Chenopodia . 76 Diospyros 79 Choice of seed . 183 Dirca 73 Climbing stems . 101 Diseases 279 Coccus 42,290 Distorted stems 173 Cochlearia . 56 Dodecatheon 77 Collet described . 92 Drill sowing 188 Composite . 80 Durability of timber 110 Conclusion . 320 Duration of trees 63 Conducting organs . . 10 Coniferae . 63 Constitution of a tree . 148 E. Constitutional character 62 metamor- Ebenacesc 79 phosis 173 Eggs of insects 303 Constriction of the bark 287 Elseaginea 73 Convertible husbandry 275 Electrising principle of the Convolvulaceae . 78 sun's rays 132 Corylus - 66 Elephantopus 80 Crassulacese . 81 Empetrea2 63 Creeping steins . 103 English elm 70 Cross impregnation . 269 Enkianthus 105 Crystallisation . 135 Enothera 94 Cucumber . 81 Epiphyllum 80 CucurbitacepR . ib. Ergot 286 Cunninghamia . 65 Ericese 80 Cuscuta 78 Encomia . J59 INDEX. * 325 PAGE H. PAGE Euphorbium . 72 Excremental power of Haemanthus 53 plants 275 Haltica 296 Experiment by Mr. J. Heartwood, changes of 109 Knight 181 Helianthus 96 Exudations . 158 Hollow elms 137 Hop 71 Humulus 96 F. Hyacinth . . 48 Hybernacula . 104, 149 Fagus . . . 67 Hydrocharidese 61 Fallowing 276 Felling timber 307 underwood 314 I; Ferruginous soils . 110 Ficoidese 18 Janipha manihot 271 Fig . . 71 Jasmin eae , 79 Fingers and toes . . 300 Jargonelle pear 101 Fintelman, Mr. 165 Impatiens 83 Flowering shrub pruning 260 Impregnation 263 Foreign seeds 187 Indian Archipelago 75 Fore-shortening . 232 Indusium 136 Forest tree pruning 223 Infinite divisibility of Formica 302 plants 138 Fragaria 95 Insects, destructive 290 Fraxinus 79 Internodes 147 pendula 95 Ipomaea 78 Fruit-tree pruning 237 Iridese 58 Fungi . . 6 ,27 Irregular growth 227 Juglandese 68 Juncus filiformis 95 G. Justicia 159 Genera 23 K. Georgina 56 Gladiolus 56 Knight, T. A. Esq., Glands 157 P. H. S. . 116, 167 Gloxinia . . 153 Knight, Mr. J., experi- Gooseberry moth 302 ment by 181 Gossipium 84 Gourd 81 L. Grafting 208 Graminea 5 33 Labiata 77 Grubbing . , 315 Lachenalia 53 326 INDEX. PAGE N. PACK Larch, manner of growth 103 Large trees 318 Nelumbiuin . 56 ,84 Larix pendula 95 Nepenthes 73 Laurinae 75 Nettle 71 Lathraea 77 Nutritive organs 9 Layering 207 Nyctaginese 76 Leaves 150 of pliyllanthus 153 0. Leguminosse 82 Leontodon 56 Oak in ancient buildings 111 Liatris 128 Olinese 79 Liber 136 Opuntia ib. Ligneous fibres 113 Opuntiaccae 80 Limnocharis 158 Orchards, failures of 258 Linum 84 Orchidese 59 Long shoot pruning 244 Orchis 56 Longevity of trees . 317 Organisable property of sap 139 Lopping 234 Orobaucheae 77 Lychnis coronaria 95 P. M. Paconia . . 56 ,97 Magnolia 260 Palmse 39 Maiden earth 274 Pandaneae 39 Malalcuca 82 Papaver 181 Mammalaria . 156, 80 Passiflorese 81 Manure 276 Plantain 58 Marvel of Peru 76 Platanus 67 Mayduke cherry 165 Pendulous stems 100 Mealy aphis 292 Peneacese 80 Medullary rays 147 Persea . . 75 Melon 81 Phaseolus 96 Merulius 28 Philadelphus 95 Mespilus 159 Phillanthus 73 Mildew . 282 Phoenix 43 Monocotyledones . 25 Phytolaceae 76 Monstrous flowers 171 Pinus strobus 65 Morello cherry . 165 sylvestris 64 Mother branch pruning . 243 Piperaceas . 69 Musaeeae 58 Piper betel ib. Myoporinse 77 Pith described 97 Myristicese 74 Populus 66 Myrtacese 82 Preservative organs 12 INDEX. 327 PAGE PAGE Primary buds . 143 Saracenia 84 Primulaceae . 76 Satin wood 103 Polyanthus Narcissus . 50 Scitaminese 59 Polygoneae . 75 Scolytus destructor 305 Progressive growth . 103 Seat of vegetable life 132 Propagation . 202 Seed, description of 85 Proteaceoe . 74 Seedling stem 106 Protuberance on an Elm 126 Seedtime 190 Pruning . 222 Sexual organs 169 transplanted tree: 3 194 Sinapis arvensis 181 melons . 262 Siphonia 73 Pucinia graminis . 32 Solaneae 77 Pyrus . 156 Solanum tuberosum 57, 78 Soldanella 76 Sowing 175 Q. Smut 285 Spanish chestnut 67 Quality of tiniber . 313 Special habit 63 Quercus . 67 Spiral vessels 112 Spur pruning 246 Spurious stems 151 R. Stapelia 79 Stem described 93 Red acarus, or tick . 301 Subdivision of vital mem- Reproduction . 62 brane 142 Reproductive organs . 13 Swelling of a stem above Rhododrendron . 260 a ligature . 123, 128 Ricinus . 73 Swietenia 94 Root, description of . 87 Systematic divisions 23 Rosacea . 82 Rose trees . 260, 304 T. Rubiacese . 80 Taxodium 64 Taxus ib. S. Tectonia 94 Telopia 74 Saccharum officinalis . 271 Tendrils 157 Salix . 66 Thrips 302 Babylonica . 77 Thymelise 73 Salts . 304 Tilia 84 Santalacese . 73 Timber, structure of 111 Sap described . 114 Tools of woodman 309 homogeneousness of . 149 Traditional maxim of Sap wood . 109 woodmen 311 328 INDEX. PAGE PAGE Training, examples of . 255 Vegetable matter . 67 purposes of . 254 hybrids . 265 Transplanting . . 191 Vegetation, &c. . 1 old trees . 197 Verbascuin . 265 Tremella . 30 Verbenaceae . 77 Trenching, uses of . 277 Vital envelope . 133 Truffle . 29 Vitis vinifera 9599 Tuberous stems . 96 Tulip . 45 Tulipace? . 54 W. Twining sterns . 95 Weevil . 300 Willow holts . . 234 u. Willows . 67 Wire worm . 299 Ulex . 156 Wood described . . 98 Ulmaceae . 70 Woods raised from seed 189 Umbelliferae . 80 Wounds on trees . 108 Underwood pruning . 236 Wurnalls . 306 Uredo . 283 Urticeae . 71 Uses of members . 159 X. Xylophylla . 73 V. Vallisneria . 61 Z. Vegetable elements . 2 life . 14 Zamia . 60 food . 271 Zea . 72 amplification . 149 Zones of wood . 107 THE END. BRADBURY AND EVANS, 1 B* d 2 rw ^ ft w *" 3 g -t^e S Hj fL d ^< Js O wa S p> p ^* w III w r JrP 3 ^ P* p, 5. 5^ %o ^5 P D- ^0 | ? L^i ^ hi 3 > 'go r 11 I E & ^jj * M BIOLOGY LIBRARY G UNIVERSITY OF CALIFORNIA LIBRARY L