Pen Re Ra Ue etirn ty Mt irae Hehe i nes Ove a se Yara iy tale SPE aL Hehe Nex ee art ALBERT R.. MANN LIBRARY CORNELL UNIVERSITY THE SURVIVAL OF THE UNLIKE IN PRESS: THE EVOLUTION OF OuR NATIVE FRUITS. Uniform with this volume. Profusely illustrated. THE SURVIVAL OF THE UNLIKE A COLLECTION OF EVOLUTION ESSAYS SUGGESTED BY THE STUDY OF DOMESTIC PLANTS BY L. H. BAILEY The study of domestic productions will rise immensely in value. —Darwin, Origin of Species. Botanists have generally neglected cultivated varieties as beneath their notice. —Darwin, Animals and Plants under Domestication. SECOND EDITION Netw Work THE MACMILLAN COMPANY LONDON: MACMILLAN & CO., Lrp. 1897 All rights reserved Mann SPEC. COE. QR G%O Bet. Ia9 7 COPYRIGHT, 1896 By L. H. BAILEY Set up and electrotyped August, 1896 Reprinted March, 1897 Mount Pleasant Printery J. Horace McFarland Company Harrisburg, Pa. THE MEMORY OF . dksa Gray --LAMENTED AND LOVED OF ALL WHO LOVE NATURE— IS THE AUTHOR’S UNCEASING INSPIRATION. PREFACE. For several years it has been my habit, when called upon to address horticultural societies, to choose some topic intimately associated with the evolution of domestic plants. My motives have been several. I have chiefly desired to attempt to answer many of the common questions which puzzle horticulturists by ap- pealing to the evidences of evolution, for I am con- vinced that many of these questions can be answered in no other ‘way. I have also desired to spread a knowledge of the evolution speculations and of the methods of research which they suggest, amongst those who deal with plants and animals, and who lead a rural life. Again, I have wished to make a record of a great class of most common and significant facts vitally related to the study of organic evolution, but which are almost wholly overlooked by students and philosophers. In making these essays, I have con- stantly had in mind the collation and publication of them, and I have, therefore, endeavored to discuss the leading problems associated with the variation and evolution of cultivated plants, in order that the final collection should be somewhat consecutive. The results of this intermittent labor I now give (1) 2 PREFACE. to those for whom it was from time to time conceived, —for horticulturists first, for evolutionists next. The essays are of unequal merit, and there are necessarily repetitions in them; but I conceive that they are the more valuable for having been written at different times and for different occasions, for they thereby pre- sent the subjects in more diverse aspects. The audi- ences to whom the greater number of the essays have been addressed have been composed of persons who observe widely of facts, but who are unused to mak- ing broad inductions from ‘them. It is only in the first two essays that I have ventured to state any general convictions respecting the bolder: problems of organic evolution, but I count these of much less merit than the statements of many plain and simple facts of observation and experiment which are made in the humbler essays. If the author has been fortu- nate enough to make any contribution to positive sci- ence in these pages, it is probably that associated with the vexed question of bud-variation, which is chiefly presented in the third essay; but even this is novel only in its treatment. The underlying motive of the collection is the emphasis which is placed upon unlikenesses, and of their survival because they are unlike. The author also denies the common assump - tion that organic matter was originally endowed with the power of reproducing all its corporeal attributes, or that, in the constitution of things, like produces like. He conceives, as explained on pages 20 to 24, PREFACE. ‘3 that heredity is an acquired force, and that, normally or originally, unlike produces unlike. It may be well to state what are the chief lines of proof of evolution as they appeal to the author. A priori reasons for belief in the hypothesis are the two facts, that there must be struggle for existence from the mere mathematics of propagation, and that there have been mighty changes in the physical char- acter of the earth. These facts argue that organisms must either have changed or perished. To me, the chief demonstrative reason for belief in evolution is the fact that plants and animals can be and are modi- fied profoundly by the care of man. In fact, I should be convinced that the organic creation is an evolution if I had no other proof than this. But the proofs are abundant: 1. Those afforded by paleontology. 2. Those of embryology. 3. Those of comparative anatomy and structure. 4. Resemblances of types, which allow the objects to be classified. If species were specially created, there would have been no relationships. 5. The successive increase in complexity and dif- ferentiation, or divergence, in this classification, or the growth of the “‘tree of life.”’ 6. The fact of adaptation to environment. 7. The vagaries of distribution, (See Essay XV.) 4 PREFACE. 8. The fact of variation, and the frequency of in- tergradient forms. 9. The observed behavior of animals and plants under the hand of man. The reader who desires more explicit information upon the means of producing new varieties may con- sult ‘*Plant-Breeding,’’ in which some of the more ob- vious speculations which are concerned with the breed- ing of plants are set forth in some detail. Histori- cal narratives of our indigenous cultivated fruits will be found in ‘‘The Evolution of our Native Fruits.” L. H. BAILEY. CORNELL UNIVERSITY, Irnaca, N. Y., September 1, 1896. Note to the Second Issue. In this issue, a few minor alterations have been made, and a fuller statement is given to the conclud- ing paragraph of the first Essay. The author takes this occasion to say—— what, it’ would seem, is per- fectly obvious — that in his denial of design, he uses the word design in its biological significance, and that he ‘has no reference to the larger question of pur- posiveness in the creation. He refers to the notion of immediate or proximate interference in shaping the forms of life. The larger question of purposive design is one which can be neither denied nor af- firmed from biological evidence; but the author would argue that the entire evolution scheme is a nobler conception of purposive creation than any mere in- terjection of special forces into a discontinuous, and, therefore, in a meaningless, creation. November 17, 1896, PREFACE TO THE SECOND EDITION. THE publishers having called for a second edition of this book, I take occasion, in addition to making a few corrections and minor changes in the plates, to more fully express my convictions upon two or three points to which reviewers have taken exception. I do this not as a defense, but for the purpose of making my contention more clear. I should say, also, that the book, from its very nature, is not a treatise, and that it does not attempt to construct any philosophy of the progress of the evolution of plants,— a subject which the author may hope to con- sider at another time. It has been objected that the statement that un- like produces unlike cannot be strictly true, since it might follow that the offspring should be so different from the parents as not to carry over any of the parental characteristics. In other words, its logical termination might be a general scattering of forms and the absence of resemblances. All this is perfectly true, but the reader is expected to bear in mind the fact that hypotheses are methodological: their great- est purpose is to suggest a method rather than to (5) 6 PREFACE. proclaim a definite fact. The statement is fully as defensible, from the logical standpoint, as the com- moner phrase that like produces like is. The object of my phrase is to oppose the notion that the forms of life originally possessed hereditary power, or ‘that it was a part of their constitution that like should rigidly produce like, and that all variation must, there- fore, be attributed to definite agencies. My own con- ception is that the original forms of life had no cor- poreal characters (using the word character in its tech- nical or natural history sense), and therefore needed only powers of propagation, not of heredity. As the characters arose from the normal variations be- cause of the necessities of environment, so the heredi- tary power arose at the same time. In other words, the constant reproducing of a given variation by recurring similar environments developed a tendency to its perpetuation. The evolution of the organic creation seems to me to have been a constant pro- cess of suppression and elimination of miscellaneous or indefinite ‘variations, resulting in the perpetuation of certain type stems and the obliteration of the in- termediates; and early in the process the normal plasticity of the life- plasma must have been the source of some of this variation, and it is not im- probable that this type of plastic or fortuitous varia- tion is not yet wholly eliminated from the vegetable kingdom. Or, to state the matter in another form, I conceive the organic creation to have started out with PREFACE. q no definite tendencies so far as the corporeal forms of organisms are concerned, but these tendencies have all been developed—heredity amongst the rest—by the environmental necessities of later time; whilst varia- tion or plasticity was a normal and necessary feature of the original form of life, this constitutional elastic- ity has been constantly bred out by the pressure of circumstances, and the subsequent variation has come to be more and more the result of definite environ- ments. In some groups, in which the decline to- wards extinction has now well progressed, or when environments are very stable, organisms reproduce themselves with considerable rigidity, so that it may be said that like produces like. In some of the variable groups, which, presumably, have not yet reached the height of their development, it might with equal truth be said that unlike produces unlike. But in any event, the normal or original fact is con- ceived to be that unlike produces unlike. At the present time it would be truer to say that similar produces similar. It has been doubted whether the conception of the phyton be worth the while (Botanical Gazette, xxii., 501). The reviewer asks: “But do noteworthy dif- ferences exist between the successive internodes of a shoot?” It is by no means essential to the concep- tion of the phyton that the different phytons upon any branch shall be unlike; although it should be remembered that, as a matter of fact, no two branches 8 PREFACE. on a plant are alike, and yet every branch springs from a phyton. The point is that any phyton is ca- pable of making a new plant, and the characters of that new plant will be very markedly determined by the conditions under which it grows. The phyton is simply the unit of asexual propagation as the seed is of sexual propagation (see the contrasts of the keime and the knospen in Mobius’ recent “Beitrige zur Lehre von der Fortpflanzung der Gewiachse”). The word bud might be substituted for phyton, but that word now has two or three technical uses; and, more- over, it is not always necessary that actual buds be present in order that phytons shall grow when made into cuttings or grafts. “Potentially, every node and internode of the plant is an individual, for it pos- sesses the power, when removed and properly cared for, of expanding into what we call a plant, and of perfecting flowers and seeds and of multiplying its kind” (page 83). A fuller consideration of the species-dogma (see Essay IV.) was published as “The Philosophy of Species-Making” .in Botanical Gazette for last De- cember. L. H. BAILEY. IrHaca, N. Y., March 4, 1897. II. IV. CONTENTS. PART I. Essays TOUCHING THE GENERAL Fact AND PHILOSOPHY OF EVoLurion. Page The Survival of the Unlike... ......... 13 Neo-Lamarckism and Neo-Darwinism ........ 55 The Plant Individual in the Light of Evolution. The Philosophy of Bud-Variation, and its Bearing upon Weismannism ......... 2. ee eee 81 Experimental Evolution amongst Plants ....... 107 Van Mons and Knight, and the Production of Varieties 138 VI. Vi. VIII. IX. Some Bearings of the Evolution-Teaching upon Plant- Cultivation: 8c ei ce Bee ek ee Re 162 Why have our Enemies Increased? ....... 180 Coxey’s Army and the Russian Thistle. A Sketch of the Philosophy of Weediness..........- 193 Recent Progress in American Horticulture. ..... 202 PART II. Essays EXPOUNDING THE Fact AND CAUSES OF VARIATION. A. The Fact. Page X. On the Supposed Correlations of Quality in Fruits 219 XI. The Natural History of Synonyms ..... . 237 XII. Reflective Impressions of the Nursery Business . 245 XII. The Relation of Seed-Bearing to Cultivation . . 251 B. The Causes. XIV. Variation after Birth. ..... a a ee 256 (9) 10 XVI. XVII. XVIII. XIX. XXII. XXIII. XXIV. CONTENTS. Page A Pomological Alliance. Sketch of the Relation - ship between American and Eastern Asian Froit®; 6 « % <4 5 4 2 BR ee ae ee ee 267 Horticultural Geography ....- ++ ++ ees 278 Some Emphatic Problems of Climate and Plants. Comprising “Speculative Notes upon Phenol- ogy (the Physiological Constant, and the Cli- matal Modification of Phenological Phenom- ena) ;” and “Some Interrelations of eee and Horticulture” ......+.--. 288 Are American Fruits Best Adapted to aang Conditions? ..... bet ee . 311 Acclimatization: Does it Occur? ..... . . « 320 On the Longevity of Apple Trees. ..... . . 334 Sex in Fruits . : sf > ASE SA cat. ods 347 Are Novelties Worth their Cost? ... .. . . 356 Why Do Promising Varieties Fail? ....... 364 Reflections upon the Longevity of Varieties. Comprising “Do Varieties Run Out?” “Are the Varieties of Orchard Fruits Running Out?” “Studies in the Longevity of the Varieties of Tomatoes? = 2 4 6s & Se eS OR ee Coals 376 PART III. Essays TRACING THE EVOLUTION OF PARTICULAR TYPES OF XXV. XXVI. XXVIII. XXVIII. PLANTS. , Page Whence Came the Cultivated Strawberry?. . . . 400 The Battle of the Plums. ......... - . 418 The Evolution of American Grapes. ..... . 481 The Progress of the Carnation. Comprising “Types and Tendencies in the Carnation;” “John Thorpe’s Ideal Carnation;” and “Bor- der Carnations” ...... SP ak Ss - . 438 PREFACE. XXX. The Amelioration of the Garden Tomato. Com- prising “ The Origin of the Tomato from a Mor- phological Standpoint ;” “History of the Trophy Tomato;” “The Probable Course of Evolution of the Tomato;” and “Direction of Contemporaneous Improvement of the To- mato” a 11 Page I. THE SURVIVAL OF THE UNLIKE.’ WE all agree that there has been and is evolution; but we probably all disagree as to the exact agencies and forces which have been and are responsible for it. The subject of the agencies and vehicles of evolution has been gone over repeatedly and carefully for the animal crea- tion, but there is comparatively little similar research and speculation for the plant creation. This deficiency upon the plant side is my excuse for calling your atten- tion, in a popular way, to a few suggestions respecting the continuing creation of the vegetable world, and to a somewhat discursive consideration of a number of illus- trations of the methods of advance of plant types. T, Nature of the Divergence of the Plant and the Animal. ” It is self-evident that the development of life upon our planet has taken place along two divergent lines. These lines evidently originated at a common point. The common life-plasma was probably at first more ani- 1 Originally an address before the Philosophical Club of Cornell University, April 20, 1896. Revised and presented, in part, before the American Philosophical Society, Philadelphia, May 1, 1896, and printed in the proceedings of the Society. vol. xxxv. pp. 88 to 110. 14 THE SURVIVAL OF THE UNLIKE. {. mal-like than plant-like. The stage in which this life- plasma first began to assume plant-like functions is closely and possibly exactly preserved tous in that great class of organisms which are known as mycetozoa when studied by zodlogists and as myxomycetes when studied by botanists. At one stage of their existence, these or- ganisms are amceba-like, that is, animal-like, but at another stage they are sporiferous or plant-like. The initial divergencies in organisms were no doubt con- cerned chiefly in the methods of appropriating food, the animal-like organisms apprehending their food at a more or less definite point, and the plant-like or- ganisms absorbing food throughout the greater or even the entire part of their periphery. It is not my purpose to trace the particular steps or methods of these diver- gencies, but to call your attention to what I believe to be a characteristic distinction between the two lines of de- velopment, and one which I do not remember to have seen stated in the exact form in which it lies in my mind. Both lines probably started out with a more or less well marked circular arrangement of the parts or organs. This was consequent upon the peripheral arrangement of the new cells in the development of the multicellular or- ganism from the unicellular one. A long line of animal life developed in obedience to this peripheral or rotate type of organization, ending in the echinoderms and some of the mollusks. This type long ago reached its zenith. No line of descent can be traced from it, ac- cording to Cope. The progressive and regnant type of animal life appeared in the vermes or true worms, forms which are characterized by a two-sided or bilateral, and. therefore more or less longitudinal, structure. The ani- mal-like organisms were strongly developed in the 1.] ANIMALS AND PLANTS CONTRASTED. 15 power of locomotion, and it is easy to see that the rotate or centrifugal construction would place the organism at a comparative disadvantage, because its seat of sensation is farthest removed from the external stimuli. But the worm-like organisms ‘‘being longitudinal and bilat- eral,’’? writes Cope, ‘‘one extremity becomes differen- tiated by first contact with the environment.’’ In other words, the animal type has shown a cephalic, or head- forming, evolution in consequence of the bilateralism of structure. The individual has become concentrated. Out of this worm-form type, therefore, all the higher ranges of zodtypic evolution have sprung, and one is al- most tempted to read a literal truth into David’s lamen- tation that ‘‘I am a worm, and no man.”’ If, now, we turn to plants, we find the rotate or peri- pheral arrangement of parts emphasized in all the higher ranges of forms. The most, marked bilateralism in the plant world is amongst the bacteria, desmids, and the like, in which locomotion is markedly developed; and these are also amongst the lowest plant-types. But plants soon become attached to the earth, or, as Cope terms them, they are ‘‘earth-parasites.’’? They therefore found it to their advantage to reach out in every direc- tion from their support in the search for food. Whilst the centrifugal arrangement has strongly tended to dis- appear in the animal creation, it has tended with equal strength to persist and to augment itself in the plant creation. Its marked development amongst plants be- gan with the acquirement of terrestrial life, and with the consequent evolution of the asexual or sporophytie type of vegetation. Normally, the higher type of plant bears its parts more cr less equally upon all sides, and the limit to growth is still determined by the immediate en- 16 THE SURVIVAL OF THE UNLIKE. [1. vironment of the given individual or of its recent ances- tors. Its evolution has been acephalic, diffuse, or head- less, and the individual plant or tree has no proper con- centration of parts. For the most part, it is filled with unspecialized plasma, which, when removed from the parent individual (as in cuttings and grafts), is able to reproduce another like individual. The arrangements of leaves, branches, the parts of the flower, and even of seeds in the fruit, are thus rotate or circular, and in the highest type of plants the annual lateral increments of growth are disposed in like fashion; and it is significant to observe that in the composite, which is considered to be the latest and highest general type of plant-form, the rotate or centrifugal arrangement is most emphatically developed. The circular arrangement of parts is the typical one for higher plants, and any departure from this form is a specialization, and demands explanation. The point I wish to urge, therefore, is the nature of the obvious or external divergence of plant-like and ani- mal-like lines of ascent. The significance of the bilateral structure of animal-types is well understood, but this significance has been drawn, so far as I know, from a comparison of bilateral or dimeric animals with rotate or polymeric animals. I want to puta larger meaning into it, by making bilateralism the symbol of the onward march of animal evolution, and circumlateralism (if I may invent the term), the symbol of plant evolution. The suggestion, however, applies simply to the general arrangement of the parts or organs of the plant body, and has no relation to structural characteristics and relationships. It is a suggestion of analogues, not of homologues. We may, therefore, contrast these two great lines of ascent which, with so many vicissitudes, 1.J ARE PLANTS CATAGENETIC ? 17 have come up through the ages, as Dipleurogenesis and Centrogenesis. The two divergent directions of the lines or phyla of evolution have often been the subject of comment, but one.of the sharpest contrasts between the two was made in 1884 by Cope, when he proposed that the vegetable king- dom has undergone a degenerate or retrogressive evolu- tion. ‘‘The plants in general,’’ he then wrote, ‘‘in the persons of their protist ancestors, soon left a free-swim- ming life and became sessile. Their. lives thus became parasitic, more automatic, and in one sense degenerate.’’ The evolution of the plant creation is, therefore, held to be a phenomenon of ecatagenesis or decadence. This, of course, is merely a method of stating a comparison with the evolution of the animal line or phylum, and is, therefore, of the greatest service. For myself, however, I dislike the terms retrogressive, catagenetic, and the like, as applied to the plant creation, because they imply in- trinsic or actual degeneracy. True retrogressive or de- generate evolution is the result of loss of attributes. Cope holds that the chief proof of degeneracy in the plant world is the loss of a free-swimming habit; but it is possible that the first life-plasma was stationary: at any rate, we do not know that it was motile. Degeneracy is unequivocally seen in certain restricted groups where the loss of character can be traced directly to adaptive changes, as in the loss of limbs in the serpents. Re- tarded evolution expresses the development of the plant world better than the above terms, but even this is erro- neous, because plant types exhibit quite as complete an adaptation to an enormous variety of conditions as ani- mals do, and there has been rapid progress towards spe- cialization of structure. Asa matter of fact, the vege- 2 SUR, 18 THE SURVIVAL OF THE UNLIKE. [x. table world does not exhibit, as a whole, any backward step, any loss of character once gained, nor any station- ary or retarded periods; but its progress has been widely unlike that of the animal world, and it has not reached the heights which that line of ascent has attained. The plant phylum cannot be said to be catagenetic, but it is sui generis; or, in other words, it is centrogenetic, as distinguished from dipleurogenetic. The hearer should be reminded, at this point, of the curious alternation of generations which has come about in the plant world. One generation performs sexual functions, and the product of the sexual union is an asexual generation, and this, in turn, gives rise to an- other sexual generation like the first. In the low sex- plants, as in some of the alge, the sexual generation— or the gametophyte, as it is called—generally comprises the entire plant body, and the asexual generation—or sporophyte—develops as a part of the fructifying struc- ture of the gametophyte, and is recognizable as a sepa- rate structure only by students of special training. In the true mosses, the gametophyte is still the conspicuous part of the plant structure. It comprises all that part of. the moss which the casual observer recognizes as ‘‘the plant.’’ The sporophytic generation is still attached to the persistent gametophyte, and it is the capsule, with its stem and appendages. In the ferns, however, the gamet- ophytic stage is of short duration. It is the incon- spicuous prothallus, which follows germination of the spore. Therefrom originates ‘‘the fern,’’ all of which is sporophytic, and the gametophyte perishes. With the evolution of the flowering plants, the gametophyte becomes still more rudimentary, whilst the sporophyte is developed into the plant, tree or shrub, as we see it. i GENESIS OF DIFFERENCES. 19 The gametophytic generation is associated with the act of fertilization, the male prothallus or gametophyte de- veloping from the pollen grain and soon perishing, and the female prothallus or gametophyte developing in the ovule, and either soon perishing, or persisting, at least in the conifer-like plants, in the form of the albumen of the seed. The great development of the sporophyte in later time is, no doubt, a consequence of the necessity of assuming a terrestial life; and with this development has come the perfection of centro- genetic form. IL. The Origin of Differences. The causes which have contributed to the origin of the differences which we see in the organic creation have been and still are the subjects of the most violent con- troversy. Those persons who conceive these differences to have come into existence full-formed, as they exist at the present time, are those who believe in the dogma of special creations, and they usually add to the doctrine a belief in design in nature. This doctrine of special cre- ation receives its strongest support when persons con- trast individual objects in nature. Certainly nothing can seem more unlike in very fundamental character than an insect and an elephant, a star fish and a potato, a man and an oak tree. The moment one comes to study the genealogies of these objects or groups, how- ever, he comes upon the astonishing fact that the an- cestors are more and more alike the farther back they are traced. In other words, there are great series of 20 THE SURVIVAL OF THE UNLIKE. (1. convergent histories. Every naturalist, therefore, is compelled to admit that differences in nature have some- how been augmented in the long processes of time. It is unnecessary, therefore, that he seek the causes of pres- ent differences until he shall have determined the causes of the smallest or original indifferences. It is thus seen that there are two great and co-ordinate problems in the study of evolution,—the causes of initial differences, and the means by which differences are augmented. These two problems are no doubt very often expressions of the same force or power, for the augmentation of a difference comes about by the origination of new degrees of difference; that is, by new differences. It is very probable .that the original genesis of the difference is often due to the operation of the very same physiological processes which gradually enlarge the difference into a gulf of wide separation. In approaching this question of the origin of unlike- nesses, the inquirer must first divest himself of the effects of all previous teaching and thinking. We have reason to assume that all beings came from one original life- plasma, and we must assume that this plasma had the power of perpetuating its physiological identity. Most persons still further assume that this plasma must have been endowed with the property of reproducing all its characters of form and habit exactly, but such assump- tion is wholly gratuitous and is born of the age-long habit of thinking that like produces like. We really have no right to assume either that this plasma was or was not constituted with the power of exact reproduction of all its attributes, unless the behavior of its ascendents forces us to the one or the other conclusion. Inasmuch as no two individual organisms ever are or ever have 1.] UNLIKE PRODUCES UNLIKE. 21 been exactly alike, so far as we can determine, it seems to me to be the logical necessity to assume that like never did and never can produce like. The closer we are able to approach to plasmodial and unspecialized forms of life in our studies of organisms, the more are we impressed with the weakness of the hereditary power. Every tyro in the study-of protoplasm knows that the amceba has no form. The shapes which it assumes are individual, and do not pass to the descendants. To my mind, there- fore, it is a more violent assumption to suppose that this first unspecialized plasma should exactly reproduce all its minor features than to suppose that it had no distinct hereditary power, and therefore, by the very nature of its constitution, could not exactly reproduce itself. The burden of proof has been thrown upon those who attempt to explain the initial origin of differences, but it should really be thrown upon those who assume that life-matter was originally so constructed as to rigidly recast itself into one mould in each succeeding generation. I see less reason for dogmatically assuming that like produces like than I do for supposing that unlike produces unlike. I advanced this proposition a year ago in my ‘‘Plant- Breeding’’* (pages 9 and 10), and I am now glad to find, since writing the above paragraph, that H. S. Williams has reached similar conclusions in his new ‘Geological Biology.’’ He regards mutability as the fundamental law of organisms, and speaks of the prev- alent notion that organisms must necessarily reproduce *As an example of the common and unreserved acceptance of the notion that like produces like, I may cite the opinion of A. S.,in a review of Plant-Breeding in the Bulletin of the Torrey Botanica] Club (April, 1896). He dogmatically asserts that the statement that inherent plasticity of organisms may allow of variation without an immediate inciting cause, is ‘‘ certainly unscientific,” It is only fair to ask that he explain why it is, 22 THE SURVIVAL OF THE UNLIKE. fi. themselves exactly as ‘‘one of the chief inconsistencies in the prevalent conception of the nature of organisms.’’ ‘‘While the doctrine of mutability of species has gener- ally taken the place of immutability,’’ he writes, ‘the proposition that like produces like in organic generation is still generally, and I suppose almost universally, accepted. It therefore becomes necessary to suppose that variation is exceptional, and that some reason for the accumulation of variation is necessary to account for the great divergencies seen in different species. * * * * The search has been for some cause of the variation; it is more probable that mutability is the normal law of organic action, and that permanency is the acquired law.’’ I do not suppose that Professor Williams makes definite variation an inherent or necessary quality of organic matter, but that he conceives this matter to have had no original hereditary power, and that its form and other attributes in succeeding generations have been moulded into the environment, and that the bur- den of proof is thrown upon those who assume that life-matter was endowed with the property that like nec- essarily produces like. At all events, this last is my own conception of the modification of the lines of ascent. This conception of the unstable constitution of the original forms of life is by no means novel, but it ap- pears to have been held most freely by those thinkers who are not themselves professed biologists. One of the best statements of it which I know is that of E. P. Powell in his powerful book, ‘‘Our Heredity from God.’’ “But Nature never fails to remind us,”’ he says, ‘that heredity is only a slowly established tendency, and that permutation is the original tendency in nature; for, if you succeed in breaking up an established order or L] HEREDITY AN ACQUIRED CHARACTER. 23 species, you will find the most persistent effort necessary to prevent unlimited variation. * * * The difficulty is not so much to secure a new variety or a new species as it is to establish and confirm it.’’ In other words, I look upon heredity as an acquired character, the same as form or color or sensation is, and not as an original endowment of matter. The hereditary power did not originate until, for some reason, it was necessary for a given character to reproduce itself, and the longer any form or character was perpetuated, the stronger became the hereditary power. It is now pertinent to enquire what determined the particular differences which we know to have persisted. The mere statement that some forms became sessile or attached to the earth, and that others became or re- mained motile, is an assumption that these differences were direct adaptations to environment. Every little change in environment incited a corresponding change in the plastic organization; and the greater and more various the changes in the physical attributes of the earth with the lapse of time, the greater became the modifications in organisms. I believe, therefore, that the greater part of present differences in organisms are the result, directly and indirectly, of external stimuli, until we come into those higher ranges of being in which sensation and volition have developed, and in which the effects of use and disuse and of psychological states have become increasingly more important as fac- tors of ascent. The whole moot question, then, as to whether variations are definite or multifarious, is aside from the issue. They are as definite as the changes in the environment are, which determine and control their existence. More differences arise than can persist, but 24 THE SURVIVAL OF THE UNLIKE. (1. this does not prove that those which are lost are any the less due to the impinging stimuli. Those who write of definite variation usually construe the result or outcome of some particular evolution into a measure of the vari- ation which is conceived to have taken place in the group. Most or all of the present characters of any group are definite because they are the survivals in a process of elimination; but there may have been, at va- rious times, the most diverse and diffuse variations in the very group which is now marked by definite attri- butes. As the lines of ascent developed, and generation followed generation in countless number, the organiza- tion was more and more impressed with the features of ancestral characters, and these ancestral characters are the more persistent as they have been more constant in the past. But these characters, which appear as hered- itary or atavistic variations in succeeding generations, were no doubt first, at least in the plant creation, the offspring, for the most part, of the environment react- ing upon the organism. As life has ascended in the time-scale and has become increasingly complex, so the operation of any incident force must ever produce more diverse and unpredictable results. What I mean to say is that, in plants, some of the variations seem to me to be the resultants of a long line of previous incident im- pressions, or to have no immediate inciting cause. Such variation is to all appearances fortuitous. It is, there- fore, evident that the study of the effects of impinging environments at the present day may not directly eluci- date the changes which similar conditions may have pro- dueed in the beginning. Whilst the steadily ascending line of the plant crea- tion was fitting itself into the changing moods of the 1.] THE GROWTH-FORCE, 25 external world, it was, at the same time, developing an internal power. Plants were constantly growing larger and stronger or more specialized. The accumulation of vital energy is an acquired character, the same as pecu- liarities of form or structure are. It is the accumulated result of every cireumstance which has contributed to the well-being and virility of the organism. The gar-- dener knows that he can cause the plant to store up energy in the seed, so that the resulting crop will be the larger. Growth is itself but the expression or result of this energy which has been picked up by the way through countless ages. Now, mere growth is varia- tion. It results in differences. Plants cannot grow without being unlike. The more luxuriant the growth, the more marked the variation. Most plants have ac- quired or inherited more growth-force than they are able to use, because they are held down to certain limitations by the conditions in which they are necessarily placed by the struggle for existence. J am convinced that many of the members of plants are simply outgrowths resulting from this growth-pressure, or, as Bower sig- nificantly suggests (‘‘A Theory of the Strobilus in Ar- chegoniate Plants,’’ Annals of Botany, viii. 358, 359), they are the result of an ‘‘eruptive process.’’ The push- ing out of shoots from any part of the plant body, upon occasion, the normal production of adventitious plant- lets upon the stems and leaves of some begonias (espe- cially Begonia phyllomaniaca), bryophyllum, some ferns, and many other plants, are all expressions of the growth- foree which is a more or less constant internal power. This growth-force may give rise to more definite varia- tions than impinging stimuli do; but the growth-force runs in definite directions because it, in its turn, is the 26 THE SURVIVAL OF THE UNLIKE. [r. survival in a general process of elimination. Many of the characters of plants which—for lack of better ex- planation—we are in the habit of calling adaptive, are no doubt simply the result of eruption of tissue. Very likely some of the compounding of leaves, the pushing out of some kinds of prickles, the duplication of floral organs, and the like, are examples of this kind of variation. "We know that the characters of the ex- ternal bark or cortex upon old tree trunks are the re- sult of the internal pressure in stretching and splitting it. This simply shows how growth-force may origi- nate characters of taxonomic significance when it is expressed as mere mechanical power acting upon tissue of given anatomical structure. This power of growth is competent, I think, to originate many and important variations in plants. I suppose my conception of it to be essentially the same as that of the bathmism of Cope, and the ‘‘theory of the organic growth’’ of Eimer. Darwin seems to have come near to the same law when he supposed that excess of food supply is the chief cause of variation, for he thereby recognizes the correlation of growth and variability; but in his conception, the growth is the result of a direct and immediate external stimulus, and not an internal acquired force. We have now considered two general types of forces or agencies which start off variations in plants,—purely external stimuli, and the internal acquired energy of growth. There is still a third general factor, crossing, or, as Eimer writes it, ‘‘sexual mixing.’’ The reason for the very existence of sex, as we now understand it, is to originate differences by means of the union of two parents into one offspring. (See Essay II.) This sexual mixing cannot be considered to be an original 1.] DARWIN’S PHILOSOPHY. 27 cause of unlikeness, however, since sex itself was at first a variation induced by environment or other agencies, and its present perfection, in higher organisms, is the result of the process of continuous survival in a conflict of differences. The recent rise of Lamarckian views seems to have been largely the result of an attempt to discover the vera causa of variations. Darwin’s hypothesis of natural selection assumes variability without inquiring into its cause, and writers have therefore said that Darwin did not attempt to account for the cause of variations. Nothing can be farther from his views. Yet some of our most recent American writings upon organic evo- lution repeat these statements. Cope, in his always admirable ‘‘Primary Factors of Organie Evolution,’ writes that ‘‘Darwin only discussed variation after it came into being.’’ Yet Darwin’s very first chapter in his ‘‘Origin of Species’? contains a discussion of the ‘Causes of variability,’’ and the same subject is gone over in detail in ‘‘ Variation of Animals and Plants under Domestication.’’ Darwin repeatedly refers the cause or origin of variation to “‘changed conditions of life,’’ which is essentially the position maintained by the Lamarckians, and he as strenuously combats those who hold that definite variation is an innate attribute of life. ‘But we must, I think, conclude * * *,’’ writes Darwin in the latter book, ‘‘that organic beings, when subjected during several generations to any change what- ever in their conditions, tend to vary.’’ He discussed at length the particular agencies which he considered to be most potent in inducing variability, and enumerated, amongst other factors, the kind and amount of food, climate, and crossing. ‘‘Changes of any kind in the 28 THE SURVIVAL OF THE UNLIKE. [r. condition of life,’’ he repeats, ‘‘even extremely slight changes, often suffice to cause variability. Excess of nutriment is perhaps the most efficient single exciting eause.’”?’ (See Essay XIV.) Cope, in his discussion of the ‘‘Causes of variation,’’ starts out with the propo- sition ‘‘to cite examples of the direct modifying effect of external influences on the characters of individual animals and plants;’’ and he closes with this paragraph: ‘‘T trust that I have adduced evidence to show that the stimuli of chemical and physical forces, and also molar motion or use and its absence, are abundantly sufficient to produce variations of all kinds in organic beings. The variations may be in color, proportions, or details of structure, according to the conditions which are present.’’ This is, in great part, the thesis to which Darwin ex- tended the proofs of a most laborious collection of data from gardeners and stock-breeders and from feral nature. It has been the great misfortune of the interpretation of Darwin’s writings that his hypothesis of natural selec- tion has so completely overtopped everything else in the reader’s mind that other important matters have been overlooked. Whilst the one central truth in the plant creation is the fact that differences arise as the result of variations in environment, there are, nevertheless, many exceptions to it. There are various types of differences, which are merely incidental or secondary to the main stem of adaptive ascent. Some of these are such as arise from the cessation of the constructive agencies, and others are mere correlatives or accompaniments of type differences. As an example of the former, we may cite the behavior of the potato. By high cultivation and careful breeding, the plant has been developed to produce enormous crops 1.] PANMIXIA, 29 of very large tubers, so heavy a crop that the plant has been obliged’ to spare some of its energy from the pro- duction of pollen and berries for the purpose of main- taining the subterranean product. It is evident that this high state of amelioration can be maintained only by means of high cultivation. The moment there is a let- down in the factors which have bred and maintained the plant, there is a tendency towards a breaking up and disappearance of the high-bred type. This is an illus- tration of the phenomenon of panmixia, as outlined by Weismann, except that the force which has ceased to act is human selection rather than natural selection. ‘‘This suspension of the preserving influence of natural selec- tion,’’ Weismann writes, ‘‘may be termed Panmixia.’’ In his opinion, ‘‘the greater number of those variations which are usually attributed to the direct influence of external conditions of life are to be attributed to pan- mixia. For example, the great variability of most domesticated animals and plants essentially depends upon this principle.’’ In other words, certain differences are preserved through the agency of natural selection, and certain differences are lost; if the organism is re- moved from this restraining and directing agency, all variations have the chance of asserting themselves. ‘‘All individuals can reproduce themselves,’’? Weismann explains, ‘‘and thus stamp their characters upon the species, and not only those which are in all respects, or in respect to some single organ, the fittest.’’? I am con- vineed that this term expresses a very important truth, and one which, as Wiesmann says, is particularly ap- parent in domestic animals and plants; but panmixia does not express an original force. If new differences arise in consequence of the cessation of the directive 30 THE SURVIVAL OF THE UNLIKE. [r. agency of natural selection, it is because they were im- pressed upon the organization by some unaccountable agency; or, if there is simply a falling away from ac- cumulated characters, the residuary or secondary features which appear are probably the. compound and often ‘deteriorated result of various previous incident forces. In short, panmixia is a name for a class of phenomena, and it eannot be considered as itself an original cause of variation. It is, to my mind, largely the unrestrained expression or unfolding of the growth-force consequent upon the removal of the pressure under which the plant has lived. Il. The Survival of the Unlike. The one note of the modern evolution speculations which has resounded to the remotest corner of civiliza- tion and which is the chief exponent of current specu- lation respecting the origin and destiny of the organic world, is Spencer’s phrase, ‘‘ the survival of the fittest.’’ This epigram is an epitome of Darwin’s law of natural selection, or ‘‘ the preservation, during the battle for life, of varieties which possess any advantage in structure, constitution or instinct.’’? In most writings, these two phrases—‘‘ natural selection’’ and ‘‘the survival of the fittest ’’—are used synonymously; but in their etymology they really stand to each other in the relation of process and result. The operation of natural selection results in the survival of the fittest. One must not be too exact, however, in the literal application of such summary ex- pressions as these. Their particular mission is to afford 1.J PHRASEOLOGY OF EVOLUTION. 31 a convenient and abbreviated formula for the designation of important principles, for use in common writing and speech, and not to express a literal truth. Darwin was himself well aware of the danger of the literal interpre- tation of the epigram ‘‘ natural selection.’’? ‘‘The term ‘natural selection,’’’ he writes, ‘‘is in some respects a bad one, as it seems to imply conscious choice; but this will be disregarded after a little familiarity.’? This tech- nical use of the term ‘‘natural selection’’ is now gen- erally accepted unconsciously; and yet there have been recent revolts against it, upon the score that it does not itself express a literal principle or truth. If we accept the term in the sense in which it was propounded by its author, we are equally bound to accept ‘‘ survival of the fittest’? as a synonymous expression, because its author so designed it. ‘‘ By natural selection or survival of the fittest,’’ writes Spencer, ‘‘“—by the preservation in suc- cessive generations of those whose moving equilibria happen to be least at variance with the requirements, there is eventually produced a changed equilibrium completely in harmony with the requirements.’’ It should be said that there is no reason other than usage why the phrase ‘‘ survival of the fittest’? should not apply to the result of Lamarckian or functional evo- lution as well as of Darwinian or selective evolution. It simply expresses a fact without designating the cause or the process. Cope has written a book upon the ‘‘Origin of the Fittest,’’ in which the argument is Lamarckian. The phrase implies a conflict, and the loss of certain contest- ants and the salvation of certain others. It asserts that the contestants or characters which survive are the fittest, but it does not explain whether they are fit because en- dowed with greater strength, greater prolificness, com- 39 THE SURVIVAL OF THE UNLIKE. {r. pleter harmony with surroundings, or other attributes. I should like to suggest, therefore, that the chief merit of the survivors is unlikeness, and to call your attention for a few minutes to the significance of the phrase— which I have used in my teaching during the last year — the survival of the unlike. This phrase—the survival of the unlike—expresses no new truth, but I hope that it may present the old truth of vicarious or non-designed evolution in a new light. It defines the fittest to be the unlike. You will recall that in this paper I have dwelt upon the origin and pro- gress of differences rather than of definite or positive characters. Iam so fully convinced that, in the plant creation, a new character is useful to the species because it is unlike its kin, that the study of differences between individuals has come to be, for me, the one absorbing and controlling thought in the contemplation of the pro- gress of life. These differences arise as a result of every impinging force,— soil, weather, climate, food, training, conflict with fellows, the strain and stress of wind and wave, and insect visitors,—as a complex resultant of many antecedent external forces, the effects of crossing, and also as the result of the accumulated force of mere growth; they are indefinite, non-designed, an expression of all the various influences to which the passive vege- table organism is or has been exposed; those differences which are most unlike their fellows or their parents find the places of least conflict, and persist because they thrive best, and thereby impress themselves best upon their off- spring. Thereby there is a constant tendency for new and divergent lines to strike off, and these lines, as they become accented, develop into what we, for convenience sake, have called species. There are, therefore, as many 1.] . SPORTS. 33 species as there are unlike conditions in physical and environmental nature, and in proportion as the condi- tions are unlike and local are the species well defined. But to Nature, perfect adaptation is the end; she knows nothing, per se, as species or as fixed types. Species were created by John Ray, not by the Lord; they were named by Linneeus, not by Adam. I must now hasten to anticipate an objection to my phrase which may arise in your minds. I have said that when characters are unlike existing characters, they stand a chance of persisting; but I do not desire to say that they are useful in proportion as they are unlike their kin. I want to express my conviction that mere - sports are rarely useful. Sports are no doubt the result of very unusual or complex stimuli or of unwonted re- frangibility of the energy of growth, and not having been induced by conditions which act uniformly over a course of time, they are likely to be transient. I fully accept Cope’s remark that there is ‘‘no ground for be- lieving that sports have any considerable influence on the course of evolution. * * * The method of evolution has apparently been one of successional increment and decrement of parts along definite lines.’’ Amongst do- mestie animals and plants the selection and breeding of sports, or very unusual and marked variations, has been a leading cause of their strange and diverse evolution. In fact, it is in this particular thing that the work of the breeder and the gardener is most unlike the work of nature. But in feral conditions, the sport may be likened to an attribute out of place; and I imagine that its chief effect upon the phylogeny of a race—if any effect it have—is in giving rise in its turn to a brood of less erratic unlikenesses. This question of sports has 3 SUR. 34 THE SURVIVAL OF THE UNLIKE. (i. its psychological significance, for if the way becomes dark the wanderer invokes the aid of this ignis fatuus to cut short his difficulties. Sir William Thomson suggests that the basis of life may have come to earth upon a meteor, and Brinton proposes that man is a sport from some of the lower creation. It is certainly a strange conception which ascribes a self-centered and self-sufficient power to the tree of life, and then, at the very critical points, adopts a wholly extraneous force, and one which is plainly but a survival of the old cata- clysmic doctrines; and it is the stranger, too, be- cause such type of explanation is not suggested by ob- servation or experiment, but simply by an insuperable barrier of our present ignorance of: natural processes. If evolution is true at all, there is reason to suppose that it extends from beginning to finish of creation, and the stopping of the process at obscure intervals can be only a temporary satisfaction to one who is not yet fully committed to the eternal truth of ascent. The tree of life has no doubt grown steadily and grad- ually, and the same forces, variously modified by the changing physical conditions of the earth, have run on with slow but mighty energy until the present time. Any radical change in the plan would have defeated it, and any mere accidental circumstance is too trivial to be considered as a modifying influence of the great on- ward movement of creation, particularly when it as- sumes to account for the appearing of the very cap- stone of the whole mighty structure. Bear with me if I recite a few specific examples of the survival of the unlike, or of the importance, to or- ganic types, of gradually widening differences. Ilus- trations might be drawn from every field of the organic 1.] THE GARDENER’S POWER. 35 creation, but I choose a few from plants because these are the most neglected, and because I am most familiar with them. These are given to illustrate how important external stimuli are in originating variation, and how it is that some of these variations persist. Let me begin by saying that a good gardener loves his plants. Now, a good gardener is one who grows good plants, and good plants are very unlike poor plants. They are unlike because the gardener’s love for them has made them so. The plants were all alike in Novem- ber; in January, the good gardener’s plants are strong and clean, with large, dense leaves, a thick stem, and an abundance of perfect flowers; the poor gardener’s plants are small and mean, with curled leaves, a thin, hard stem, and a few imperfect flowers. You will not believe now that the two lots were all from the same seed-pod three months ago. The good gardener likes to save his own seeds or to make his own cuttings; and next year his plants will be still more unlike his neighbor’s. The neighbor tries this seed and that, reads this bulletin and that, but all avails nothing, simply because he does not grow good plants. He does not care for them tenderly, as a fond mother cares for a child. The good gardener knows that the temperature of the water and the air, the currents in the atmosphere, the texture of the soil, and all the little amenities and comforts which plants so much enjoy, are just the factors which make his plants successful; and a good crop of anything, whether wheat or beans or apples, is simply a variation. And do these unlikenesses survive? Yes, verily! The greater part of the amelioration of cultivated plants has come about in just this way,—by gradual modifica- tions in the conditions in which they are grown, by 36 THE SURVIVAL OF THE UNLIKE. [1. means of which unlikenesses arise, and then by the se- lection of seeds from the most coveted plants. Even at the present day, there is comparatively little plant- breeding. The cultivated flora has come up with man, and if it has departed immensely from its wild proto- totypes, so has man. The greater part of all this has been unconscious and unintended on man’s part, but it is none the less real. As an illustration of how large the factors of unde- signed choice and selection are in the amelioration of the domestic fiora, let me ask your attention to the bat- tle of the seed-bags. In the year 1890 the census rec- ords show, for the first time, the numbers of acres in the United States devoted to the growing of seeds. I give the acreage of three representative crops, and these figures I have multiplied by the average seed-yields per acre, in order to arrive at an approximate estimate of the entire crop produced, and the number of acres which the crop would plant. I have used low averages of yields in order to be on the safe side, and I have like- wise used liberal averages of the quantity of seed re- quired to plant an acre when making up the last column: Acres in Average yields Approximate seed-crops. per acre. crop of seeds. Would plant Cabbage .... 1,268 200 Ibs. 253,600 Ibs. 1,014,400 acres. Cucumber . - 10,219 120 “ 1,226,280 ‘* 613,140 Tomato «4,356 80 ‘* 368,480 ‘ 1,473,920 The last column in this table has particular interest, because it shows the enormous acreage which these seeds, if all planted, would cover. We are now curious to know if such areas really are planted to these species, and if they are not, it will be pertinent to inquire what becomes of the seeds. Unfortunately, we have no sta- tistics of the entire acreages of these various truck- garden crops, but the same census gives the statistics of 1.] BATTLE OF THE SEED-BAGS. 37 the commercial market-gardens of the country. Inquiry of seed-merchants has convinced me that about one- fourth of all the seeds sold in any year go to market-gar- deners. I have therefore multiplied the census figures of market gardens by four for the purpose of arriving at an estimate of the total acreage of the given crops in the United States; and I have introduced the last column from the previous table for purposes of comparison : Acreage of Probable There are seeds market-gardens. total acreage. enough to plant Difference. Cabbage. ....- 77,094 308,376 1,014,400 acres. 706,024 acres. Cucumber .. 4,721 18,884 613,140 ** 594,256 ‘ Tomato. . . 22,802 91,208 1,473,920“ 1,382,712 “* It will thus be seen that there are enough cabbage seeds raised in this country each year—if the census year is a fair sample—to plant nearly three-quarters of a million acres more than actually are planted; about the same surplus of cucumber seeds; and a surplus of tomato seeds sufficient to plant over one and a quarter million acres. It is possible, of course, that the figures of actual acreage of these crops are too low; but such error, if it occur, must be much overbalanced by the large quanti- ties of home-grown and imported seeds which are used every year. These startling figures would not apply so well to many other crops which are detailed in the cen- sus bulletin. For instance, the peas raised in this coun- try would plant only about 46,000 acres, whilst there are over 100,000 acres actually grown; but this discrepancy is probably accounted for by the fact that the larger part of the seed peas are grown in Canada, and therefore do not figure in our census. There is a somewhat similar discrepancy in the watermelon, but in this crop the seeds are very largely home-saved by the heavy planters in the south and west. I do not give these figures for their 38 THE SURVIVAL OF THE UNLIKE. Lt. value as statistics, but simply for the purpose of graph- ically expressing the fact that many more seeds are raised by cultivators each average year than are ever grown into plants, and that struggle for existence does not necessarily cease when plants are taken under the care of man. What, now, becomes of this enormous surplus of seed? Let us take a rough survey of the entire seed erop of any year. In the first place, a certain percentage of the seeds are laid aside by the seedsman as a surety against failure in the year to come. Much of this old stock never finds its way into the market, and is finally discarded. We will estimate this element of waste as 20 per cent. Of the 80 per cent. which is actually sold, perhaps another 10 per cent. is never planted, leaving about 70 per cent. which finds its way into the ground. These two items of loss are pure waste, and have no effect upon the resulting crop. Now, of the seeds which are planted, no more than 75 per cent. can be expected to germinate. That is, there is certainly ‘an average loss of 25 per cent. in nearly all seeds—and much more in some—due to inherent weakness, and 75 per cent. rep- resents the survival in a conflict of strength. We have now accounted for about half of the total seed product of any year. The remaining half produces plants; but here the most important part of the conflict begins. In the crops mentioned above, much less than half of the seeds which are grown ever appear in the form of a crop. We must remember, moreover, that in making the esti- mate of the number of acres which these seeds would plant, I have used the usual estimates of the quantity of seeds required to plant an acre. Now, these estimates of seedsmen and planters are always very liberal. Every 1.] DISRUPTION OF SPECIFIC TYPES. 39 farmer sows from five to twenty times more seed than he needs. Some years ago, I sowed seeds according to the recommendation of one of our best seedsmen, and I found that peas would be obliged to stand four-fifths of an inch apart, beets about twenty to the foot, and other vegetables in like confusion. I suppose that of all the seeds which actually come up, not more than one in ten or a dozen, in garden vegetables, ever give ma- ture plants. What becomes of the remainder? They are thinned out for the good of those which are left. This simple process of thinning out vegetables has had a most powerful effect upon the evolution of our domestic flora. It is a process of undesigned selection. This selection proceeds upon the differences in the seed- lings. The weak individuals are disposed of, and those which are strongest and most unlike the general run are preserved. It is a clear case of the survival of the un- like. The laborer who weeds and thins your lettuce bed unconsciously blocks out his ideas in the plants which he leaves. But all this is a struggle of Jew against Jew, not Jew against Philistine. It is a conflict within the species, not of species against species. It, therefore, tends to destroy the solidarity of the specific type, and helps to introduce much of that promiscuous unlikeness which is the distinguishing characteristic of domestic plants. Let us now transfer this emphatic example to wild nature. There we shall find the same prodigal pro- duction of seeds. In the place of the gardener unde- signedly moulding the lines of divergence, we find the inexorable physical circumstances into which the plastic organisms must grow, if they grow at all. These cir- cumstances are very often the direct causes of the 40 THE SURVIVAL OF THE UNLIKE. {r. unlikenesses of plants, for plants which start like when they germinate may be very unlike when they die. Given time and constantly but slowly changing condi- tions, and the vegetable creation is fashioned into the un- likenesses which we now behold. With this conception, let us read again Francis Parkman’s picturesque descrip - tion of the forests of Maine in his ‘‘ Half-Century of Conflict:’’ ‘‘For untold ages Maine had been one un- broken forest, and it was so still. Only along the rocky seaboard or on the lower waters of one or two great rivers a few rough settlements had gnawed slight in- dentations into this wilderness of woods, and a little farther inland some dismal clearing around a blockhouse or stockade let in the sunlight to a soil that had lain in shadow time out of mind. This waste of savage vege- tation survives, in some part, to this day, with the same prodigality of vital force, the same struggle for existence and mutual havoc that mark all organized beings, from men tomushrooms. Young seedlings in millions spring every summer from the black mold, rich with the decay of those that had preceded them, crowding, choking, and killing each other, perishing by their very abun- dance; all but a scattered few, stronger than the rest, or more fortunate in position, which survive by blighting those about them. They in turn, as they grow, inter- lock their boughs, and repeat in a season or two the same process of mutual suffocation. The forest is full of lean saplings dead or dying with vainly stretching towards the light. Not one infant tree in a thousand lives to maturity; yet these survivors form an innumer- able host, pressed together in struggling confusion, squeezed out of symmetry and robbed of normal de- velopment, as men are said to be in the level sameness 1.] EVOLUTION OF THE ROOT. 41 of democratic society. Seen from above, their mingled tops spread in a sea of verdure basking in light; seen from below, all is shadow, through which spots of timid sunshine steal down among legions of dark, mossy trunks, toadstools and rank ferns, protruding roots, matted bushes, and rotting carcasses of fallen trees. A generation ago one might find here and there the rugged trunk of some great pine lifting its verdant spire above the indistinguished myriads of the forest. The woods of Maine had their aristocracy; but the axe of the wood- man has laid them low, and these lords of the wilderness are seen no more.”’ In such bold and generalized examples as this, the student is able to discern only the general fact of pro- gressive divergency and general adaptation to conditions, without being able to discover the particular directive forces which have been at the bottom of the evolution. It is only when one considers a specific example that he can arrive at any just conclusions respecting initial causes of modification. Of adaptive modifications, two general classes have been responsible for the ascent of the vegetable kingdom; one a mere moulding or shaping into the passive physical environments, the other the direct result of stress or strain imposed upon the organ- ism by wind and water, and by the necessities of a radical change of habit from aquatic to terrestrial life, and later on by the stimuli of insects upon the flowers. One of the very best examples of the mere passive ascent is afforded by the evolution of the root as a feeding organ; and a like example of development as a result of strain is afforded by the evolution of the stem and vas- cular or fibrous system. Our present flora, like our pres- ent fauna, is an evolution from aquatic life. The first 42 THE SURVIVAL OF THE UNLIKE. [x. sessile or stationary plants were undoubtedly stemiess. As the waters increased in depth, and plants were driven farther and farther from their starting points by the struggle for place and the disseminating influence of wind and waves, the plant body became more and more elongated. Whilst the plant undoubtedly still absorbed food throughout its entire periphery, it nevertheless began to differentiate into organs. The area chiefly concerned in food-gathering became broadened into a thallus, a constricted or stem-like portion tended to develop below, and the entire structure anchored itself to the rock by a holdfast or grapple. This holdfast or so-called root of most of our present sea-weeds is chiefly a means of holding the plant in place, and it probably absorbs very little food. As plants emerged into amphibian life, however, the foliar portion was less and less thrown into contact with food, and there was more and more demand upon the grapple which was anchored in the soil. The foliage gradually developed into organs for absorbing gases, and the root was forced to absorb the liquids which the plant needed. I do not mean to say that there is any genetic connection between the sea- weeds and the higher plants, or that the roots of the two are homologous; but to simply state the fact that, in point of time, the hold-fast root developed before the feeding-root did, and that this change was plainly one of adaptation. Specialized forms of flowering plants, which inhabit water, still show a root system which is little more than an anchor, and the foliage actively absorbs water. The same environmental circumstances are thus seen to have developed organs of similar physi- ological character in widely remote times and in diverse lines of the plant evolution. ‘‘As the soil slowly became 1.] EVOLUTION OF THE ROOT. 43 thicker and thicker,’’ writes King in his book upon “The Soil,’’ ‘‘as its water-holding power increased, as the soluble plant food became more abundant, and as the winds and the rains covered at times with soil portions of the purely superficial and aérial early plants, the days of sunshine between passing showers and the weeks of drought intervening between periods of rain became the occasions for utilizing the moisture which the soil had held back from the sea. These conditions, coupled with the universal tendency of life to make the most of its surroundings, appear to have induced the evolution of absorbing elongations, which by slow degrees and cen- turies of repetition came to be the true roots of plants as we now know them.’’ Some aquatic flowering plants are, as we have seen, still practically rootless, and they absorb the greater part of their food directly by the foliar parts; but the larger number of the higher plants absorb their mineral food by means of what has come to be a subterranean feeding organ, and the foliar parts have developed into gas-absorbing organs, and they take in water only when forced to do so under stress of cir- eumstances. But as a mere feeding organ, the root requires no fibrous structure. It is still a hold-fast or grapple, and its mechanical tissue has developed enormously, along with that of the stem, in order to preserve the plant against the strain of the moving elements and to main- tain its erectness in aérial life. When this self-poised epoch arrives, the vegetable world begins its definite and steady ascent in centrogenie form. Whilst the animal creation leaves its centrogenic arrangement early in its own time-scale, the plant creation assumes such arrange- ment at a comparatively late epoch in its time-scale. 44 THE SURVIVAL OF THE UNLIKE. (1. Perhaps the best illustration which I can bring you of the origin of the unlike by means of environmental conditions, and the survival of some of this unlikeness in the battle for life, is the development of the winter qui- escence of plants. What means all this bursting verdure of the liquid April days? Why this annually returning miracle of the sudden expansion of the leaf and flower from the lifeless twigs? Were plants always so? Were they designed to pass so much of their existence in this quiescent and passive condition? No! The first plants had no well-defined cycles, and they were born to live, not to die. There were probably no alternations of sea- sons or even of days, in the primordial world. The ac- count in Genesis places the creation of plants in the third cosmogonic day, and the setting of ‘‘lights in the firma- ment of heaven’’ to ‘‘ be for signs, and for seasons, and for days, and years,’’ in the fourth day. As late as the Carboniferous time, according to Dana, the globe ‘‘ was nowhere colder than the modern temperate zone, or be- low a mean temperature of 60° F'.”’ The earth had be- come wonderfully diverse by the close of the Cretaceous time, and the cycads and their kin retreated from the poles. Plants grew the year round; and as physical conditions became diverse and the conflict of existence increased, the older and the weaker died. So a limit to duration,—that is, death,— became impressed upon the individuals of the creation; for death, as seen by the evolutionist, is not an original property of life-matter, but is an acquired character, a result of the survival of the fittest. The earth was, perhaps, ages old, even after life began, before it saw a natural death; but without death all things must finally have come to a standstill. When it became possible to sweep away the old types, 1.] ‘THE VARIATION IN LONGEVITY. 45 opportunity was left for new ones; and so the ascent must continue so long as physical conditions which are not absolutely prohibitive of life shall become unlike. Species have acquired different degrees of longevity, the same as they have acquired different sizes and shapes and habits,—by adaptation to their conditions of life. Annual plants comprise about half of the vegetable king- dom, and these are probably all specializations of com- paratively late time. Probably the greater part of them were originally adaptations to shortening periods of growth,— that is, to seasonal changes. The gardener, by forceful cultivation and by transferring plants towards the poles, is able to make annuals of perennials. Now, a true annual is a plant which normally ripens its seeds and dies before the coming of frost. Many of our gar- den plants are annuals only because they are killed by frost. They naturally have a longer season than our climate will admit, and some of them are true perennials in their native homes. These plants are, with us, plur- annuals, and amongst them are the tomato, red pepper, ege-plant, potato, castor bean, cotton, lima bean, end many others. But there are some varieties of potatoes and other plants which have now developed into true an- nuals, normally completing their entire growth before the approach of frost. It is all the result of adaptation to climate, and essentially the same phenomenon is the development of the annual and biennial flora of the earth from the perennial. An interesting example of the effect of climate upon the seasonal duration of plants is the indeterminate or prolonged growth of plants in England as compared with the same plants in America. The cooler summer and very gradual approach of winter in England develop a late and indefinite maturity of the 46 THE SURVIVAL OF THE UNLIKE. i. season’s growth. When English plants are grown in America, they usually grow until killed by fall frosts; but after a few generations of plants, they acquire the quick and decisive habit of ripening which is so charac- teristic of our vegetation. I once made an extended test of onions from English and American seeds (Bull. 31, Mich. Agric. College), and was astonished to find that nearly all of the English varieties continued to grow until frost and failed to ‘‘bottom,’’ whilst our domestic varieties ripened up in advance of freezing weather. This was true even of the Yellow Danvers and Red Wethersfield, varieties of American origin and which could not have been grown very many years in Eng- land. Every horticulturist of much experience must have noticed similar unmistakable influences of climate upon the duration of plants. A most interesting type of examples of quick infiu- ence of climate upon plants—not only upon their dura- tion but upon habit and structural characters—is that associated with the growing of ‘‘stock seed’’ by seeds- men. Because of uncertainties of weather in the eastern states, it is now the practice to grow seeds of onion, lima bean and other plants in California or other warm regions; but the plants so readily acquire the habit of long-continuing growth as to be thereafter grown with difficulty in the northeastern states. It is, therefore, necessary that the seedsman shall raise his stock seed each year in his own geographical region, and this seed is each year sent to California for the growing of the commercial seed crop. In other words, the seed of Cali- fornia-grown onions is sold only for the purpose of growing onion bulbs for market, and is not planted for the raising of a successive crop of seed. This results in 1.] THE WINTER PASSIVITY. 47 growing only a single generation of the crop in the warm country. Onion seed from stock which has been grown in California for several years is considered to produce onions which do not ‘‘bottom,’’ much as I found to be the case with the English onion seed. But some plants, in geologic time, could not thus shorten up their life-history to adjust themselves to the oncoming of the seasons. They ceased their labors with the approach of the cold or the dry, tucked up their tender tissues in buds, and resigned themselves to the elements. If a man could have stood amongst those giant mosses and fern forests of the reeking Carbonif- erous time, and could have known of the refrigeration which the earth was to undergo, he would have ex- claimed that all living things must utterly perish. -Consider the effects of a frost in May. See its wide- spread devastation. Yet, six months hence the very same trees which are now so blackened will defy any degree of cold. And then, to make good the loss of time, these plants start into activity relatively much earlier in spring than the same species do in frostless climates. This very day, when frosts are not yet passed, our own New York hillsides are greener with surface vegetation than the lands of the Gulf states are, which have been frostless for two months and more. The frogs and turtles, the insects, the bears and foxes, all adjust themselves to a-climate which seems to be absolutely prohibitive of life, and some animals may freeze dur- ing their hibernation, and yet these April days see them again in heyday of life and spirits! What a wonderful transformation is all this! This enforced period of quiescence is so impressed upon the organiza- tion that the habit becomes hereditary in plants, and 48 THE SURVIVAL OF THE UNLIKE. [t. the gardener says that his begonias and geraniums and callas must have a ‘‘rest,’’ or they will not thrive. But in time he can so far break this habit in most plants as to force them into activity for the entire year. These budding days of April, therefore, are the songs of re- lease from the bondage of winter which has come on as the earth has grown aged and cold. I must bring still one more illustration of the survi- val of the unlike, out of the abundance of examples which might be cited. It is the fact that, as a rule, new types are variable and old types are inflexible. The stu- dent of fossil plants will recall the fact that the lirio- dendrons, ginkgos, sequoias, sassafrasses and other types came into existence with many species, and are now go- ing out of existence with one or two species. Williams has considered this feature, for extinct animal forms, at some length in his new ‘‘Geological Biology.’’ ‘‘ Many species,’’ he writes, ‘“which by their abundance and good preservation in fossil state give us sufficient evi- dence in the case, exhibit greater plasticity in their char- acters at the early stage than in later stages of their history. A minute tracing of lines of succession of species shows greater plasticity at the beginning of the series than later, and this is expressed, in the systematic description and tabulation of the facts, by an increase in the number of the species.’’ ‘‘When species are studied historically, the law appears evident that the characters of specific value * * * present a greater degree of range of variability at an early stage in the life-period of the genus than in the later stages of that period.’’ So marked is this incoming of new types in many cases that some students have supposed that actual special creation of species has occurred at these epochs. f,,| PLASTICITY OF NEW TYPES. 49 It should be said that there is apt to be a fallacy in ob- servation in these instances, because the records which are, to our vision, simultaneous in the rocks may have extended over ages of time; but it is nevertheless true that some important groups seem to have come in some- what quickly with many or several species, and to have passed out with exceeding slowness. To my mind, all this is but the normal result of the divergence of character, or the survival of the unlike. A new type finds places of least conflict, it spreads rap- idly and widely, and thereby varies immensely. It isa generalized type, and therefore adapts itself at once to many and changing conditions. A virile plant is intro- duced into a country in which the same or similar plants are unknown, and immediately it finds its opportunity and becomes a weed, by which we mean that it spreads and thrives everywhere. Darwin and Gray long ago elucidated this fact. The trilobites, spirifers, conifers, ginkgos, were weed-types of their time, the same as the composites are to-day. They were stronger than their contemporaries, the same as our own weeds are stronger than the cultivated plants with which they grow. After a time, the new types outran their oppor- tunity, the remorseless struggle for existence tightened in upon them, the intermediate unlikenesses had been blotted out, and finally only one or two types remained, struggling on through the ages, but doomed to perish with the continuing changes of theearth. They became specialized and inelastic; and the highly specialized is necessarily doomed to extinction. Such remnants of a vanquished host remain to us in the equisetums and tree-ferns, in our single liriodendron, the single ginkgo and sassafras, and the depleted ranks of the conifers. 4 SUR. 50 THE SURVIVAL OF THE UNLIKE. {r. My attention was first called to this line of thought by contemplating upon the fact that cultivated plants differ widely in variability, and I was struck by the fact that many of our most inextricably variable groups—as the cucurbits, maize, citrus, and the great tribes of composites—are still unknown in a fossil state, presum- ably because of their recent origin. Many other varia- ble genera, to be sure, are well represented in fossil spe- cies, as roses (although these are as late as the Eocene), pyrus, prunus, and musa; but absolute age is not so significant as the comparative age of the type, for types which originated very far back may be yet in the com- parative youth of their development. The summary conclusions of a discussion of this subject were pre- sented to the American Association for the Advance- ment of Science two years ago.* ib wae 2 « 864 Variegation ..... oa 192 Varietal difference . . 536, $39 Vedalia c Se Soa ay wy lS Vegetables, mia Of va . 139 Vergil, quoted... ... ....201 Vermes. Sie ake Wee) Jeg IA Westiges: sci oan eat 288 Vilmorin, cited . . 438, 453, 469, 472 — on tomato a wt eo oe 418, 187 Vine, acclimatization of + «823 Violets,sportsin. . ae @ @ 2 Virginia, Albemarle Pippin oo e 2 244 Vitality of fruit-trees . . . . . 230 Vitis Labrusca .. . - « 235, 432 — vinifera - 423 et seq. Volta, mentioned .... .. .142 Von Martens. on beans .... . - 129 —Mohl, mentioned . ..... 85 Vroom, quoted < es «= 20 Waite, M.B., cited . . . 353 Wales, New South, at ‘World's Fair, ete... ..- « . 281, 282 Wallace, quoted - 182, 220, 333 Walnut i oh 2. BR — acclimatization... ..... 826 —nativity of .. 4 Sos ROE Ward,cited ... tw ee 97 Waring, Geo. E., and the Trophy tomato . - 480 et seq. Washington, acclimatization . «326 —at’World’s Fair . . . 281, 282 et seq. Watermelon, seed-crop ..... 37 —selectionin - © eee bd Watermelons to Purdue's a) Yee ZIG Watson on maize teen ww o 3 128 Weatherandplants .. .... .302 Weediness vee «2193 Weeds in the Gaadigt. sae E18: —fromabroad ...... + «188 —spreadof ...... 192, 193 et seq. Weed-types . . Seas US é 49. Weeping varieties a Rs ated onda" 9D Weismann, quoted. . . . 29, 62, 63, 65, 70, 72, 78, 75, 77, 78, 102, 265, 348, 495 — mentioned . . 61, 62, 66, 67, 68, 69, 70, 71, 76, 101, 103, 106, 167, 168, 261, 263 Weismannism. . 64, 79, 81, 103, 167, 264 Wheat: ws. 6 wa al ee DBT — acclimatization ........ .382 —andclover.........+.. .259 —and Russian thistle... .. .195 — variation in . a ee Sy SOT Williams and Morrow, mentioned, 270 —H.S8.,quoted....... 21, 48, 492 Williamson, cited ........ 2441 Willows fies ta a - 100 Willow, weeping ...-...... 99 Windbreaks .... 0 «2 ee ss . 808 Winds and fruit culture: +s ee . 808 INDEX. 015 PAGE PAGE ‘Wineberry, nativityof ...... 276 | Wright, Charles, mentioned . . . . 270 Winslow, Isaac, mentioned » 216 | Yellows of peach . - 188, 427 Winter, adaptation to. . . 44,47 | Zea amylacea Daa? » “ieheeide. 1B fe 128 Wisconsin at World's Fair . 280 et seq. | —amylea-saccharata .......- 128 — fruits in . goa Wo Bie 309 | —canina ..... ee) te hes a gl 8: Wood, Wm., quoted 2... . 421 | —everta iow Bw Gey ee 128 World's Fair, carnations at... .463 | —indentata.. . «.«.2+.+ 128 —— exhibit at . . . 278 | —saccharata Bas Bea Be Se 128 Worms, numberof ..... - .139 | —tunieata....-- o« 2 128 —true. . see ee. TS | Zizania aquatica... .. fen B29 Wormwood stanewaea se £82) Bones of plantg «+ 2 «5 x we 2 285 The Rural Science Series. Edited by Pror. L. H. BAILEY. THE SOIL. . ITS NATURE, RELATIONS, AND FUNDAMENTAL PRINCIPLES OF MANAGEMENT, By FRANKLIN H. KING, Professor of Agricultural Physics, University of Wisconsin. 16mo. Cloth. 303 pages. Price, 75 cts. CONTENTS: Introduction.—Sunshine and its Work, The Atmosphere and its ‘Work, Water and its Work, Living Forms and their Work, Over and Over Again; The Nature, Functions, Origin, and Wasting of Soils; Texture, Composition, and Kinds of Soil ; Nitrogen of the Soil ; Capillarity, Solution, Diffusion, and Osmosis; Soil Water ; Conservation of Soil Moisture ; Dis- tribution of Roots in the Soil; Soil Temper vate ; Relation of Air to Soil; Farm Drainage; Irrigation; Physical Effects of Tillage and Fertilizers. COMMENTS. * “T consider it a most desirable addition to our agricultural literature, and a distinct advance over previous treatises on the same subject, not only for popular use, but also for students and specialists, who will find many new and useful suggestions therein.” E. W. H1LGarp, Director of Agricultural Experiment Station, Berkeley, Cal. THE SPRAYING OF PLANTS. By E, G. LODEMAN, Instructor in Horticulture in Cornell University. 16mo. Cloth. 399 pages. Price, $1.00. CONTENTS. ParTI. The History and Principles of the Spraying of Plants. ParRT II. Specific Directions for the Spraying of Cultivated Plants. COMMENTS. ‘““This volume of the Rural Science Series not only gives a complete history of this comparatively new and important subject, but is a valuable manual as well, which should bein the hands of every farmer, gardener and fruit-grower. I shall take pleasure in recommending it to my students and others,” 7 5 : 4 B. C. BUFFUM, The University of Wyoming Agricultural College, Laramie, Wyo. “This is a book for every gardener and every one who has a garden, for every fruit-grower and every farmer. The necessity of spraying for a great variety of garden, field, and fruit crops is now so generally recognized that a manual on the subject has become a necessity. The destruction of injurious insects and fungi occupies an important place in the operations of gardeners, farmers, and fruit-growers, and the very careful and elaborate manner in which the subject is treated in this volume is highly creditable to the author, and commends it to the attention of every cultivator."—Vick's Monthly, ; THE MACMILLAN COMPANY. 66 Fifth Avenue, NEW YORK. The Rural Science Series. Edited by Pror. L. H. BAILry. IN THE PRESS. THE APPLE. By L. H. BAILEY. The work is tocomprise two parts—the ‘first treating of all the practicai matters of apple-growing, and the second of such scientific matters as the botany of the apple, its history and evolution, piecaetae of new varieties, and the like. It is expected that the work will be completed and ready for publication in the fall, MILK AND ITS PRODUCTS. By H. H. WING. THE FERTILITY OF THE LAND. By I. P. ROBERTS. Other volumes tn the series to follow are: Physiology of Plants. By J. C. ARTHUR, of Purdue University. Grasses. By W. H. BREWER, of Yale University. Bush Fruits. By F. W. Carp, of University of Nebraska. Plant Diseases. By B. T. GanLoway, HE. F. Smitu, and A. F. Woods, of the United States Department of Agriculture. Seeds and Seed Growing. By G. H. Hicks, of the United States Department of Agriculture. Leguminous Plants. By E. W. Hincarp, of the University of California. Feeding of Animals. By W. H. Jordan, of Maine Experiment Station. Irrigation. By F. H. Kine, of the University of Wisconsin. IN PREPARATION. EVOLUTION OF OUR NATIVE FRUITS. By L. H. BAILEY. THE MACMILLAN COMPANY. 66 Fifth Avenue, NEW YORK. The Garden - Craft Series. Edited by Pror. L. H. BAILEy. ‘THE HORTICULTURIST’S RULE-BOOK. a COMPENDIUM OF USEFUL INFORMATION FOR FRUIT-GROWERS, TRUCK- GARDENERS, FLORISTS, AND OTHERS. By L. H. BAILEY, Professor of Horticulture in Cornell University. Third Edition, Thoroughly Revised and Recast, with Many Additions. 16mo, 302 pages. Cloth, Limp, 75 Cents. This volume is the only attempt ever made in this country to codify and con- dense all the scattered rules, practices, recipes, figures and histories relating to horticultural practice in its broadest sense. All the approved methods of fighting insects and plant diseases used and discovered by all the experiment stations are set forth in shape for instant reference. sy Among the additions to the volume in the oa edition are: A chapter upon ‘Greenhouse and Window-garden Work and Estimates ;” a chapter on “Literature,” giving classified lists of the leading current writings on Ameri- can horticulture ; lists of self-fertile and self-sterile fruits; a full account of the method of predicting frosts and of averting their injuries; a discussion of the aims and methods of phenology; the rules of nomenclature adopted by botanists and horticultural societies; score-cards and scales of points for judging various fruits, vegetables and flowers; a full statement of the metric system, and tables of foreign money. * PLANT -BREEDING. By L. H. BAILEY. 16mo. 293 pages. Cloth, Limp, $1.00. Uniform with ‘The Horticulturist's Rule-Book.” CONTENTS. The Fact and Philosophy of Variation. Borrowed Opinions, of B. Verlot, E. The Philosophy of the Crossing of A. Carriére, and W. O. Focke, on Plants. . Plant-Breeding. Specific Means by which Garden Detailed Directions for the Crossing Varieties originate. of Plants. COMMENTS. , ‘I have read the work on ‘ Plant Breeding’ by Prof. L. H. Bailey with keen interest, and find it just what I expected from such a source; viz.) a most sat- isfactory treatise on a subject of most pressing horticultural importance. I shall earnestly commend the work to ray horticultural classes.” ¢ - . E. J. WicKxson, Agricultural Experiment Station, Berkeley, Cal. “The treatment is both scientific and practical, and will enable gardeners and horticulturists to experiment intelligently in cross-breeding, The sub- ject is fully elaborated, and made clear for every intelligent reader. Professor pales enon: nnded upon Oe labor and observations in original vestigations, is still further enhance the presentati i aaual Pees Mone y presentation of this excellent THE MACMILLAN COMPANY, 66 Fifth Avenue, NEW YORK. The Garden-Craft Series. Edited by Prof. L. H. BaILey. THE NURSERY-BOOK. By L. H. BAILEY. New Edition. Thoroughly recast and revised. 16 mo, Cloth, $1. This little manual has been one of the most popular of all current horti- cultural books, It contains no discussions of the theory or physiology of the propagation of plants, but it isa simple and practical account of all the ways in which plants are multiplied. It has found a wide circulation, both amongst nurserymen and amateurs. Many new illustrations have been made for this edition, bringing the number of cuts up to over 150. In its revised form, the Nursery Book is the most complete propagating manual in the language. THE, FORCING- BOOK, A MANUAL OF THE CULTIVATION OF VEGETABLES IN GLASS HOUSES. By L. H. BAILEY. 16 mo, Cloth, $1, This is a handbook of instructions upon the forcing of vegetables for mar- ket, and is the completest work of the kind yet published in this country. It is based on years of careful experimentation at the Cornell University Station, and a long familiarity with the forcing business as practiced in many parts of the country. It contains full estimates of the cost of heating forcing houses, and of the labor necessary torun them. There is also an illustrated chapter on the con- struction of forcing houses, and another on their management. IN PREPARATION. THE PRUNING-BOOK. By L. H, BAILEY. It is strange that the one subject upon which horticulturists have always asked the most questions should be wholly without a treatise. The subject of pruning is so vitally connected with every horticultural occupation, and the questions which it presents are so numerous and so difficult of answer, that nothing less than an entire volume can ever set people right in respect to it. Professor Bailey has been making definite experiments and observations upon the subject for a number of years, and the resultsof these labors are now approaching readinesss for publication. The work will comprise the culture tange of the theory and practice of pruning, both of fruit and ornamental trees and bushes, and it is expected to be on sale early in 1897.