PAM haph apa adil lee fide sb Wis 41] Sebo nl [isda ape are on eee eeicied Hb devel ee tls cana Se HC Ma TP HEM a i Ns L 4 =r aaa er "cra i dot == os == aaa seal feet on z bet} ti nt me y eit as kes ay nes pirat eu Ware BEAS Als be Nee A insite Mh ala ‘i dy ce . at rls Seah Hag aa asa a rae E ‘i ake phir ee Ya ater atl. d het eS ae Han en Dee aL ws a4 i ar Urn, cs ci pe eae ee Hie Ai Pe ie eg! ry vinta PheyaGt MT es pect He ee f i tay Seay rept 4 P (tong ‘ Tee Pa nite lace Sasi ef ins i Recep ety ee ii ; i f " Homan iret sea fant ; BE fe tt Sates \ SS OED ee i It We den SER ae eee pet rin f y isin i i) srt r 7 net hfe re reat a sats aes Retailer hat rresibelees ea pipe oot eee Fi AGI hak LD isis Peele ene F ris pimiyi ls salt Sty he 5 q pais setae ee et an i ae i Plaesiet ie rie Pee es ee ee ee E reO ee deserts f' ornare * “. MAG tt tn es ot iets crete Hi Puna tide as — ee pire : Rotaenecen gece ont Breer Pea . r ea fret one me = ABUL ae i a Ss ; PS Poh He fe pe Ase ceuett tt i ra ; a ie eae eset “i te ha ee aaNet H 3 : ie ee i aaa os Neate eta gan ea iy ie at i fi at f A eer es : eu i ie ana athe ; et ey Permits ee nape rg ee yh a =o antares rita eae fone ler tetas andegep Ae aoe ae itt bee fr f aegis - * ri reset rate Dhey ite X a neil ttt Peete ; oar s i MHC TER ches Pa thot eed Sy eee i nt ey HS ita Sacnt aru tt tight ee 8 ty i “es 7 erage z pont it i i i ah i - i fei Waa oy pleat aids it ie ALBERT R. MANN LIBRARY New York STATE COLLEGES OF AGRICULTURE AND HOME ECONOMICS AT CORNELL UNIVERSITY aK 505.Ba1 University Library introduction to cryptogamic botany. WN UCA 3 1924 000 415 236 — mm INTRODUCTION TO CRYPTOGAMIC BOTANY. BY TH REV. M. J. BERKELEY, MA, ELS. PEARL AARARARAAATS WITH 127 ILLUSTRATIONS ON WOOD, DRAWN BY THE AUTHOR, RRA AR AAA A An LONDON: H. BAILLIERE, PUBLISHER, 219, REGENT STREET; AND 290, BROADWAY, NEW YORK, U.S. : PARIS: MESSRS. BAILLIERE ET FILS, RUE HAUTEFEUILLE. MADRID: BAILLY BAILLIERE, CALLE DEL PRINCIPE. 1857. i, BS [THE RIGHT OF TRANSLATION IS RESERVED. 146530 TO SIR W. J. HOOKER, K.H., LL.D., D.C.L. Oxon., F.R.S. L.& E., F.LS., &¢., &., CORUESPONDING MEMBER OF Ohe Aratemivs uf Srieme of Paris, Berlin, Ke., THIS WORK IS DEDICATED, IN TOKEN OF THE MOST SINCERE GRATITUDE AND RESPECT, BY HIS OBLIGED SERVANT, M. J. BERKELEY. PREFACE. THE want of some especial Treatise on Cryptogamic Plants has long been felt by British botanists. The last edition of the English translation of Sprengel’s Introduction to the Study of Cryptogamic Plants appeared in 1819; and whatever the merits of that work may be, it is wholly inadequate to supply the requisite information now. Dr. Burnett’s Outlines of Botany contained some valuable notices respecting Cryptogams; and more recently, The Vegetable Kingdom of Dr. Lindley, especially the second edition of that admirable work, has brought together a mass of informa- tion, which is a most important acquisition to the student who has not access to the multitudinous works in which more modern discoveries are registered. Nor must I pass without notice The Micrographic Dictionary of Dr. Griffith and Mr. Henfrey, remarkable alike for the copiousness of the matter and the beauty of many of the illustrations. These, however, are not special treatises, nor calculated to supply completely the necessities of the student. Nor, indeed, can I point out any treatise in a foreign language, a translation of which would have come up com- pletely to the requisite standard. Bischoff’s Kryptogamische Gewdchse is admirable as far as it goes, but the design so ably begun was never completed; Eisengrein’s Hinleitung is without illustrations, and extends only to alge and lichens; and Payer’s Botanique Cryptogamique, notwithstanding the beauty and correctness of its very numerous engravings, is too slight in many parts to supply all that may reasonably be required, nor would it be possible for any English publisher, without the use of the original steel blocks, to reproduce it with any chance of remuneration. vill It is not, indeed, supposed that the present work is without glaring faults, of which no one can be more sensible than the Author. Whatever faults, however, it may contain, they are not in general ascribahle to carelessness, An incredible amount of labour has been bestowed upon its preparation, in the exami- nation of herbaria, the consultation of authorities, and the verification of facts. Nor has he rested on his own judgment, but has profited by the counsel of friends, who have in moré than one instance contributed valuable notes on subjects in which they are the highest authorities. Sir W. J. Hooker not only opened his rich Herbarium and Library, but gave much oral information on Ferns, Mosses, and Jungermannie ; Dr. Hooker supplied some admirable notes on the geographical distribution of Ferns, besides giving much advice on a variety of subjects during the progress of the work ; and Mr. Churchill Babington has contributed far the greater part of the informa- tion on the distribution of Lichens. The Author’s most grateful thanks are due to these and other Botanists who have so readily acceded to his wishes, or have taken interest in his labours. It remains only to state that the work is not intended nor calculated for persons who have not already some general knowledge of Botany. At the same time it is believed, unless the Author has entirely failed in his attempt, that there is no part which is not intelligible to any one who has made himself master of Dr. Lindley’s or Dr. Balfour’s Introductions to the Study of Botany. Kine’s Cuirrs, February 16th, 1857. ERRATA. Page 4, for Cycads read Zamic. 8, for Hastig read Hartig. 10, for Browne read Broome. 27, for paradoxan read paradoxum. 32, for Birch read Beech. 64, for sorices read scolices. 81, for alliances read divisions. 107, for Nityphyllum read Nitophyllum. 140, for propagation read fructification. 141, for microscopium read microscopicum. 142, for albuminous read aluminous. 145, for forming read form. 244, for velutinus read velutipes. 255, line 7, for immense read large. 290, for oronata read coronata. 316, for graminum read graminis. 355, for Nemetelia read Nematelia. 368, substitute A for P, in lines 2, 4, and 15. 379, for nearly read only. 398, for this read their. 420, line 14, strike out lampblack. 461, for Gappert read Berendt. ADDENDA Page 77. Meneghini has figured annular vessels in Sargassum linifolium See Alghe Italiane, &c., Tav. 1. Page 104. For directions for mounting microscopic specimens, see p. 420. Page 282, The terms applied by Tulasne to the secondary or male fruit of Spherie and Lichens, require explanation to those who are not in possession of his Memoirs When the fruit is conceived to be merely secondary, the peri- thecia are termed pycnidia, and their fruit stylospores ; where it is supposed to be of sexual importance, the perithecia are styled spermatogonia, and their deciduous granules spermatia. Stylospores and spermatia may, however, be produced on threads not inclosed in perithecia. The term conidia is applied to such secondary granules as are neither stylospores nor spermatia. Page 547. Hofmeister has lately given an account of the germination of the spores of Botrychium Lunaria in Bonplandia. AN INTRODUCTION TO CRYPTOGAMIC BOTANY. PRELIMINARY OBSERVATIONS. 1. A glance at the vegetable world, accompanied by nothing more than average powers of tact and observation, at once recognises the fact, that the members of which it is composed belong to several different divisions, more or less precisely shadowed out, and presenting distinctions readily appre- hended by the practised eye, though perhaps at the same time incapable, if at all, of strict definition, without much study and reflection. The palms, grasses, and lilies, for instance, will be distinguished long before the peculiarities of their flowers, much less the intimate structure of their seeds, are so much as conjectured; and various groups in the other grand co- ordinate, as Umbellifers, Leguminosa, and Labiates, will, with equal certainty, be separated from the general mass, though meanwhile individual groups of the two grand classes of flowering plants will occasionally be confounded or mis- placed, and far more members of subordinate divisions; and this not so much from want of correct observation, for I am not at present assuming any accurate examination of their component parts, as from the prevalent habit of confounding analogy with affinity. Thus, in popular language, species of Lamium and Urtica will pass under the same generic name, and Mymphea will be supposed to have something to do 1 2 INTRODUCTION TO CRYPTOGAMIC BOTANY. with Liliwm.* Attentive study will soon prove the two grand divisions above-named of Exogens and Endogens to be founded in nature, as far as any divisions can be shown to be so, by their mode of germination, the law of increase in their stems, and the venation of their leaves ; and so in the minor groups, though there will be many a preconception to overthrow, still structure will as before confirm the indications of outward form, except, as said above, where such indications are mere matters of external resemblance, apart from every essential character. 2. The eye, however, will have already distinguished a third grand class,+ more distinctly indicated perhaps even than the other two, though composed of parts still more widely differing from each other. It will have seen the rocks and trees covered with pigmy forms of vegetation, often displaying nothing like a leaf, or the peculiar green tint of the vegetable world; or if something approaching to a stem and leafy appendages be present, so cramped, attenuated and filmy, at once so easily dried up by heat, and capable of being restored by moisture, as to present something at once distinguishable from ordinary vegetation. The waters, whether fresh or salt, meanwhile teem with other vegetable organisms, distinguishable at once from the mere aquatic Phznogams amongst which they grow, and * After a patient examination of germinating plants, and an atten- tive consideration of the whole question, I cannot but subscribe to the view which considers Vymphea as a true Exogen, notwithstanding some anomalies of structure in the common stem, and the peculiarities of the seed. Nor, again, can I subscribe to that view which would place Velumbium and Nymphea in different divisions, though, if that were correct, no better example could be adduced in illustration of the text. + I cannot consider Dictyogens (much less Rhizogens and Gymno- gens) ag a class of the same importance with Endogens and Exogens. They are so clearly Endogenous, notwithstanding the peculiarities of the venation or much more of the structure of the stem, which may be easily studied by English botanists in Tamus, that, unless every anomaly is to be considered as overthrowing a natural division, we must either be content to leave them in company with their allies, or give up the attempt of natural arrangement altogether. INTRODUCTION TO CRYPTOGAMIC BOTANY. 3 sometimes forming forests of vegetation as dense and almost as impervious as the jungles of the tropics. If the observer now turn to the soil itself, or to the fallen leaves and decayed twigs which are»destined to increase its mass, a multitude of new beings meet his eye; fleshy gelatinous bodies of various sizes and forms, without a trace of anything approaching to a frond, mixed with mere threads and filaments ; or carbonaceous structures, none of which can for a moment be referred to the other two grand classes of vegetables; and then when he has learnt to recognise some common attributes in these multitu- dinous forms, which lead him to comprehend them under one great division, he is cognisant of the fact, that there are other objects, often of considerable size, and sometimes acquiring the stature and in some measure the aspect of palms, covering frequently immense tracts of land to the exclusion of most other objects of vegetation, which, though forming a distinct group amongst themselves, are still referable to the other mass of organisms, at first apparently so heterogeneous, by certain peculiarities of vegetation, but more especially by the absence of those organs which are essential to the pro- duction of perfect seeds. He will indeed be hable at first, Fig. 1. A single leaflet of Stangeria paradora, a Cycad lately discovered at Port Natal, to show the peculiar venation, so closely resembling that of many ferns, from a specimen communicated by Dr. Hooker. 1 * 4 INTRODUCTION TO CRYPTOGAMIC BOTANY. as in the former instance, to make certain mistakes; he will ascribe, on a superficial view, those peculiar dwarf and tufted forms of flowering plants which occur at high altitudes in so many genera, classes, and orders, to the mosses under which name they are popularly known; he will not be able to dis- tinguish or separate the Cycads from similar but not closely related forms, and even in a more instructed period, he will marvel at the resemblance offered by the fronds Stangeria paradoxa* (Fig. 1), to certain ferns; he will confound, per- haps, some of the larger club-mosses with Conifers ; he will be liable, on an inspection of the leaves only, to suppose that such plants as the Brazilian Cupania filicifolia (Fig. 2) are ferns, so close is the resemblance which its chaffy hairs give to Fig. 2. Part of a leaf of Cupania filicifolia, from the Kew Gardens. the bipmnate leaves; and if his curiosity lead him so far as to note the vegetation which clothes the rocks in tropical rapids, he will be likely to fancy the whole group of Podos- * Jn ordinary Cycads, as Encephalartos horridus and Encephalartos pungens, the veins all spring from the base and are nearly parallel, following the configuration of the leaflet. ~ INTRODUCTION TO CRYPTOGAMIC BOTANY, temads (Fig. 3), as Algee or Liverworts (Fig. 4);* and again, Fig. 3. ah a Apinagia pusilla, Tulasne. b Mniopsis Hookeriana, Tul. ¢ Involucre of the same, From Tulasne’s Monographia Podostemacearum, Tab. 7, ii., and Tab. 8, v. Fig. 4. Sarcomitrium eriocaulum, Mitten. From Hook. Muse. Ex., Tab. 72. * Modern observers have not always been free from this danger. Witness the illustration by Corda as a Liverwort in Sturm’s Deutsch- land’s Flora, Tab. xxxiii., Nos. 26, 27, of Blandovia striata, Cda. Dicrea Wallichii, Tul. was described by Taylor under the name of Polypleurum orientale, Tay]. MSS. in Trans. Royal Irish Academy, 1836. I have not access to the work, but I believe that Taylor made the same mistake as Corda. The genus is not recorded in Lindley’s Vegetable Kingdom. 6 : INTRODUCTION TO CRYPTOGAMIC BOTANY. if his steps be turned to tropical forests, or to certain localities verging on the extremities of the temperate zones, he will find fungi in Raflesia, and much more in the whole tribe of Balanophorw. In every case, however, alike, he will “be “deceived by mere analogies, and the deception, with very rare exceptions, will tend towards the confusion of the lower Phenogams with the great class in question. It is to this class, long known under the name of Cryptogams, that our attention is to be directed in the present treatise. 3. The different parts of nature are so intimately bound together, and such unexpected resemblances occur every now and then, as if for the very purpose of arresting man for a moment in his investigations, and prevent him from supposing arrogantly that he can “find out the Almighty to perfection ;” that it is impossible to give exact definitions like those which occur in pure science, which, without a single exception, shall separate with strict accuracy any one division, great or small, from another. The difficulty is just as great when in exten- sive and truly natural genera it is desired to separate one species from another,” as when the objects of separation and * Botanists are not in general aware to what an extent this fact is exhibited in the vegetable kingdom, because for the most part they have only very imperfect materials, and therefore suppose that the distine- tions between species are far more definite than they really are. In a large herbarium like that of Sir W. J. Hooker, in which specimens exist from every part of the world where a species may chance to grow, the truth of this remark will at once be apparent; and the veriest hair- splitter will pause before he inflicts on science a multitude of names which can lead to no useful result, but, on the contrary, make botany a trackless wilderness. Dr. Hooker, who has perhaps had better oppor- tunities of realising this fact than any other botanist, has informed me more than once, that he was himself utterly unaware of the full extent of this difficulty before he undertook the preparation of the Flora Indica with Dr. Thomson. Not a single large genus which passed through their hands but exhibited the same difficulty, and in many smaller genera—take for example Tetratheca, Sm., as lately illustrated in the Flora of Tasmania—the task of ascertaining what are really species is scarcely less perplexing. In treating of ferns, we shall have especial occasion to call attention to this point, The Carices perhaps, as Dr. Hooker remarks, present the most definite characters, but even amongst these, the limits of species are not always very easily ascertained. INTRODUCTION TO CRYPTOGAMIC BOTANY. 7 definition are the main or subordinate divisions of any one great class, or even, taking nature as a whole, when the question regards the highest divisions into which her pro- ductions are evidently distributed. In all these cases, defini- tions can only be assigned with that degree of limitation which is admissible where the exception may reasonably be held to prove the rule; or in other words, we must be content with pointing out some grand and leading marks of distinction, aware all the time that cases will occur in’ which these generally decisive tests will fail, so that it will be necessary to recur to other characters to prove the real systematic position of such organisms. 4, The first grand distinction of Cryptogamic plants is that, in contradistinction to Exogens and Endogens, they consist of cells only, insomuch that these higher orders have been denominated vascular plants, while Cryptogams are called cellular. Now, though the distinction holds good of a very large number of Cryptogams, yet two undoubted divisions, at least, the Ferns and Club-mosses, exhibit decided vascular bundles, nor, even were these excluded from Cryptogams, by assigning to them a distinct class, would our definition be more safe ; for even supposing nothing like vascular bundles should occur elsewhere, or though it should be denied’ that true vascular tissue occurs in ferns, we shall still have true spiral cells amongst mosses, as in the leaves of Sphagnum and the elaters of Hepaticw; and even should the true nature of the elaters in Trichia be denied, a point which there will be occasion to consider hereafter, we shall have as true vascular tissue in Batarrea (Fig. 5) as in any Endogen or Exogen. We cannot, therefore, say that the absence of vascular tissue is the universal character of Cryptogams, nor, on the other hand, can an organism which does not contain such tissue be pronounced at once a Cryptogam. Podostemads may be found in certain states void of any appearance of vessels, and so may some other aquatics, but in some particular stage of growth spiral tissue will be found; and it must be recollected, in taking a view of such matters, that im all plants the early embryonic state consists of cellular tissue only, and 8 INTRODUCTION TO CRYPTOGAMIC BOTANY. Fig. 5. a Threads from peridium of Batarrea phalloides, P. magnified, b A portion more highly magnified. ce Threads from capillitum of Podaxon carcinomalis.* that vascular tissue is but seldom found in the young plant before germination. 5. A second character, distinctive of Cryptogams, consists in the fact that growth takes place in these plants from the tips of the threads of which they are composed and of their ramifications; or in other words, that the development is superficial. This, however, must be taken with much latitude, for when we come to particulars, the exceptions are very numerous. The rule, of course, applies to their vegetative * The threads of P. carcinomalis are rather allied to woody than to vascular tissue. They, in fact, resemble closely the elongated cells in the dark portion of the concentric rings of White Spruce Wood from the Arctic Regions, as observed lately by Dr. Hooker. A similar structure exists, in what I take to be Scotch Fir, in a piece of drift wood, picked up at Lake Laura, on the western side of Wellington Channel, and kindly communicated to me by Capt. Inglefield. It is now a well-ascer- tained fact that a spiral structure exists in some varieties of cellular tissues, and perhaps in all. Criiger’s papers in the Botanische Zeitung, 1854, and Agardh®* on the spiral structure in the cells of Algze, may be consulted on this point. Hastig figures this spiral pleurenchyme under Pinus pumitio. { A ready example to the contrary may be found in the fruit of the Horse Chesnut. ® De cellula vegetabili fibrillis tenuissimis contexté. Lunde 1852. INTRODUCTION TO CRYPTOGAMIC BOTANY. 9 part, and not to their fruit ; but even then the law is far from general. In such, Diatomacec for instance, as Isthmia, and Amphitetras, (Fig. 7), the development of the threads, though centrifugal, is by no means external; in ferns, the growth of the stems is clearly endogenous rather than acrogenous, and the same may be said of several of the more robust Alga, which seem. at first sight, to have an exogenous mode of growth (Fig. 14), while those which increase by the repeated division of the cells into four, increase towards the centre quite as much as towards the circumference. Indeed, if Hartig* and Trécul’st+ views of the development of Exogens be adopted, the mode of increase of the woody tissue resembles perfectly that of many Confervee, the new growth being supplied by the repeated division of the terminal cells of the component threads of both the alburnum and liber. It is not indeed pretended that other modes of division do not exist, but the more normal mode of growth really shows the tissue to be more closely identical with Confervee than even Agardh imagined. It is very doubt- ful, however, whether this learned algologist ever intended more than the indication of a close analogy or, to advance a step further, a distinct representation. 6. A third distinction, and one of high importance is, that though Cryptogams have, at least many of them, decided dif- ferences of sex, so that they cannot correctly be termed Agamous, there are no true pistils, neither are there anthers, supposing the proper function of anthers to be the production of pollen. The bodies which in ferns, mosses, and other of the higher Cryptogams, perform the function of pollen, and which are produced in a peculiar cellular tissue much after the fashion of pollen grains, approach much more closely in form and general appearance to spermatozoa ; and though there be sometimes distinct organs for their reception, impregnation takes place immediately by simple contact, and not by means of a thread germinating from a pollen grain. Even amongst * Hartig Ueber die Entwickelung des Jahresringes der Holzpflanzen. Bot. Zeit, 1853, p. 553. } Trécul in Ann. d. Sc. Nat. Sér. ili. vol. 17, p. 250; vol. 19, p. 157, 258. 10 INTRODUCTION TO CRYPTOGAMIC BOTANY. some of the lower Cryptogams the impregnating bodies preserve an animal type, and it is to be observed that direct proof of the function of these bodies has been elicited amongst Algz, im the first instance by Thuret,* and afterwards by Pringsheimt and his followers. Where the flagelliform appendages charac- teristic of spermatozoids disappear, as in Lichens and Fungi, there is still molecular motion ; and if Leptomitus (or as it is sometimes called Saprolegnia, Achlya, &c.), as I believe to be the case, is a true Fungal, even amongst these we shall have the animalcular form. 7. A fourth distinction of equal importance with the last is the absence, in general, of everything, so far as the spores are concerned, in the shape of an embryo.{ In every case the spores consist of one or more cells composed of two or more membranes inclosing a grumous mass, OF occasionally Fig 6. a Spores of Coleosporium pingue, Lév. magnified, shewing several germinating points arranged symmetrically. b Ditto of Podisoma fuscum, magnified as observed by myself and Mr. Browne.$ * Thuret, Recherches sur la fécondation des Fucacées, suivies d’ob- servations sur les Anthéridies des Algues. Ann. d. Sc. Nat., Sér. iv., vol. 2, p. 273. } Pringsheim in Monatsbericht der Kon. Preuss. Ak. zu Berlin, March, 1855, p. 133. { If, however, by an embryo is meant a young plant ready formed, and only waiting for the evolution of its parts, we cannot deny that the spores of many of the lower Algze and of such fungi as Antennaria Robinsonit, Mont., contain an embryo. In the latter case, however, the mode of reproduction is not apparently normal. § Gard. Chron., 1849, p. 261. Ann of Nat. Hist., Ser. 2, vol iii, p. 531. The woodcut of both these fungi was prepared before the appearance of Tulasne’s second memoir on the Uredinées, INTRODUCTION TO CRYPTOGAMIC BOTANY. 11 inclosed in an integument which is itself composed of cells.* Germination takes place by the extension of one or both of the constituent membranes, in consequence of which they are essentially acotyledonous, and in general the point of growth is indifferent,+ though sometimes, as in certain species of Uredo, Puccinia, &e. (Fig. 6), indicated by spots or apertures in the outer integument, through which the ger- minating threads protrude exactly after the fashion of pollen tubes. The spores, indeed, of such Fungi bear the closest similarity in structure to many pollen grains, though their functions are very different. These germinating tubes either reproduce the plant directly, or give rise to a membranous expansion of a peculiar form, or cushion-like swelling (prothallus), which, in due time, bears the frond, fruit, or stem proper to the species.{ In the higher Cryptogams, a single spore alone gives rise to a plant ; but even amongst the foliaceous species, as in certain mosses,§ a number * In Selaginella a portion only is cellular in the form of a little dise. The formation and thickening of this disc is all the germination which takes place in the spores, which are, however, of very different value from those of many other Cryptogams, as will be seen in the sequel. + There seems at first sight to be something like this in the fleshy seeds of Crinum, and some other allied genera, as the radicle appears at the point where the seed touches the soil ; but these bodies do not consist of a mere mass of homogeneous cells, but contain, as will be seen on close examination, a fact pointed out by Robert Brown in his Pro- dromus, a distinct embryo, as perfectly formed as in other Amaryllids. {+ It is quite clear that nothing ought to be reckoned as a cotyledon which is not present in the perfect embryo. The cotyledons may be soldered togetheras in Clintonia, much reduced as in endogens, or obso- lete as in Ouscuta, but still their presence may be regarded as almost universal in the higher plants. It is, however, clear that they cannot exist in Cryptogams where there is no embryo, and therefore perhaps one of the most unobjectionable names which has been applied to them is that of Acotyledons. The name of Pseudocotyledons or Cotyledonoids, which has been given to the germinating threads, is founded on a false notion as to the nature of their reproductive bodies, and should be rejected as calculated to mislead. Some of the higher Cryptogams, however, have an embryo, and in Selaginella the first two leaves are opposite, and have much-the appearance of Cotyledons. § Kiitzing in Linnea, vol. 8, tab. 7. 12 INTRODUCTION TO CRYPTOGAMIC BOTANY. of spores, if recorded observations are to be trusted, concur in the formation of a single plant. But whether this be so or not, it is quite certain, without having recourse to such theoretic notions as would make an Agaric to consist of a mere closely compacted mass of mucedinous filaments, bearing fruit at their apices, that many fungi arise from the confluence of mycelium germinating from many spores. Ehrenberg* has long since shown in Erysiphe and Clavaria, that numerous spores concur in the production of an individual plant; and no one can be a diligent observer of fungi under all their phases, without being convinced of the fact. How far the concurrence of a number of spores may be absolutely neces- sary is uncertain} The union by means of anastomosis is as intimate as if all the threads of the mycelium were derived from a single spore, and is not to be regarded in the same light as that kind of union which takes place in grafting amongst Phenogams; for though it is possible that in the process of budding and grafting, the divided cells of the graft or scion may, in certain rare cases, coalesce—so as to form a single cell partaking of the nature of both (a matter, however, which can be only conjectural),—as, for example, in the variety of Cytisws which bears the proper * Ehrenberg de Mycetogenesi. } Individuality amongst fungi is, after all,very different from what itis amongst Phenogams. If two trees become united by the inosculation of their roots or branches, no one would consider them as a single indi- vidual; whereas many fungi which pass for individuals originally consisted of numerous distinct plants. Take, for instance, one of those Thelephore which creep over the surface of branches, and arise from the orifices of Spherie with which the bark is studded. There may at first be a hundred distinct patches, each in itself showing all the charac- ters of the species, and in perfect fruit ; as these, however, spread, they fall in with other individuals, which become perfectly confluent, and the common patch differs only from those of which it is composed in its larger size. The hymenium is perfectly continuous, and does not ex- hibit a trace of the members of which it is constituted. No one would then hesitate to consider it an individual. Patches of moss might be- come confluent in the same way, but the commonest observer would at once see that they were mere masses consisting of a thousand or more individual plants, interlaced indeed, and almost inextricable, but still distinct. INTRODUCTION TO CRYPTOGAMIC BOTANY. 13 flowers of two distinct species on the same branch inter- mixed with others partakmg of the peculiarities of either species, —the case in general is one of mere apposition, the stock simply supplying the nutriment which is necessary for the development of the graft; and in those cases where the truncated base of one tree is supported by the inosculating roots of another, the new wood formed is due to the old stock, the nutriment from which it is developed being derived from the extraneous fountain. Unless, indeed, the visions of the descent of wood in the shape of fibres coming down from the buds which so long possessed the imaginations of first-rate physiologists, in the face of facts which were perfectly nreconcilable with their truth, are to be regarded as true: visions which are now happily exploded by the brilliant observations of Trécul.* 8. We have now then arrived at some general notion of the large mass of plants known under the name of Cryp- togams, and are prepared to give such a definition as the case admits. But before doing so, it may be well to say a few words about the name which is so generally assigned to them. If it conveys no incorrect notion, it will of course be far better to retain it, than to adopt some other of less familiar sound. It has already been observed that the denomination Acotyledons is almost unobjectionable; and perhaps if, the cognate terms of Monocotyledons and Dicotyledons were universally received, it might be as well to take it at once; but these names have given place in a great measure to the terms Endogenous and Exogenous, without however the advantage of increased precision, and as the word Pheenogams is very generally used as a collective term for flowering plants, that of Cryptogams has a decided claim in preference to others. The term Asexual plants is opposed to the fact, that sexual organs or their representatives do exist in every division ; that of Cellular plants does not accord with the whole order of ferns, without mentioning other ex- * LL, cit. supra, p. 9. 14 INTRODUCTION TO CRYPTOGAMIC BOTANY. ceptions; the term Homorgana is synonymous with Cellu- laves; the term Nemew,* applied by Fries, alludes to the fact that the spores germinate by means of a protruded thread without any indications of Cotyledons, but there are many of the lower Alge in which the spores can scarcely be said to germinate at all, and certainly protrude no thread, and the spores of the higher Cryptogams are altogether anomalous, so that the term is not more strictly definite than others; Sporophore and Sporidec indicate the nature of their organs of reproduction, which, as being destitute of an embryo (a cir- cumstance not without exception) are no true seeds ; Anantha is the same with Flowerless, a term often applied to Crypto- gams, and only applicable when the word flower is made to include stamens and pistils as well as floral envelopes, for these latter exist certainly in mosses and liverworts ; the word Acro- gens indicates the apical mode of growth, which is not however an universal character ; and finally, that of Favi, except it be * Fries, in his Systema Orbis Vegetabilis, states that four general names, may be given according as the different phases of vegetable life are taken into consideration. Thus, according to germination, they are Vemea, germinating, that is, by a thread, and not by a radicle com- posed ofa cellular system with one or more cotyledons; according to vegetation they are Cellularta, as in the greater number of species there is no vascular tissue; according to the mode of flowering they are Cryptogama ; and according to their fruit, Sporidea, destitute of an embryo. Fries then gives his reasons for preferring the word Memea to Acotyledonea: 1. Negative determinations are always of an inferior rank, and must give way to positive when accurately determined. 2. The necessity of the word for the formation of the terms Homonemee and Heteronemee, descriptive of the two great divisions of cryptogamic plants. 3. Analogy ; as, for instance, Evascularia is not to be preferred to Cellularia. 4, Because of its greater precision, for true Acotyledonous plants exist amongst Phenogams, as Cuscuta. The progress of science, however, will always indicate exceptions to any term which may be invented. New terms, however excellent, always produce a certain degree of opposition at first, and are at length unwillingly received. If the present work were published under the title of an Introduction to Nemeous Botany, half the world would not known what was meant, and the other half would set the writer down as a pedant of the first water, inter omnes res maxime vitandus. INTRODUCTION TO CRYPTOGAMIC BOTANY. 15 synonymous with Cellulares, is of a doubtful meaning. In adopting the word Cryptogams, which was originally applied rather by tact than knowledge, but is not by the progress of science exempt from the reproach of being merely superficial, I feel rejoiced not to transgress the maxim of Fries, which I believe to be deeply founded :—Churacteres essentiales plerumque maxime absconditi et acute inquirendi, cum accidentales sumul maxime superficiales. CRYPTOGAMS.—L. Brong. AcoryLeponss, Juss. De Cand. Meisn—CrtLuLares, De Cand. Lindl. (1830.) Meisn.— Homoreana Schultz—Esnxvarss, Lindl. (1833, 1845.) —Sporopnor#&, Horaninow—AnantuZ Martius (excluding Fungi). —Acrogens Lindi. (1889.)—Favi, Trautvetter—Sporipga, Fr. CELLULAR, or more rarely cellulari-vascular, flowerless plants, often destitute of stem and foliage, propagated by simple or compound microscopic spores, germinating by means of one or more simple threads, and rarely containing any embryo, sometimes producing a prothallus, which gives rise to secondary spores or young embryonic plants, increasing mostly by ad- ditions to the external surface, exhibiting sexual distinctions, diclinous or monoclinous, but never producing true stamens or pistil, and consequently possessing no true pollen, but on the contrary, impregnated by spermatozoids, either provided with or destitute of slender flagelliform motile appendages. These characters may be expressed nearly in the terms which have been applied to the whole class by authors, each of which contains much truth, modified by more or less rare exceptions. 1. Cellularia. Homorgana. Favi. 2. Acrogena. 3. Anantha. Cryptogama. 4. Sporifera. Sporidea. Nemea. (Exembryonata.) 16 INTRODUCTION TO CRYPTOGAMIC BOTANY. 9. It may be well before we proceed further, to test the practical value of the definition in one or two anomalous instances. a. Suppose, for instance, the student after a few hours rain, goes out into the open air, and sees the gravel and short grass strewed with gelatinous puckered olive-coloured masses, of which he perceived no trace a few hours before : his curiosity is excited and he is anxious to ascertain the nature of the production. Externally it presents no marked differences, and within it seems to consist of a uniform jelly, without anything to make him suppose that it can be a mass of eggs. He examines it under the microscope, and he finds that it consists of necklace-like chains of pellucid granules immersed in jelly of no definite structure. Some of these are larger then the others. He finds after a time that they change colour and increase considerably in size, though still retaining a regular outline ; presently, the matter con- tained in their cavity becomes organised, and a new neck- lace of spores is contained within it; in fact, he has a young repetition of the perfect plant, requiring only extension of parts to assume completely its size and aspect. This answers to the first part of the definition, but the plant does not ger- minate as described; he can discover no sexual indications, though germination does not take place by the protrusion of a filament, and the protoplasm of the cell at once gives rise to a new plant. He believes it to belong to the vegetable kingdom, and he feels that he has hit upon one of those exceptional cases which defy mathematical accuracy. But still he has no doubt about the matter. The plant is nostoc commune, a widely -distributed Alga, bordering very close on the gelatinous Lichens. 6. He is again attracted by some little pearl-like bodies upon a decayed stick; he carries it home with a view to examination, and the bodies have lost their soft consistence, and present little skinny bags filled with elastic fibres and dust. He finds these elastic fibres to be most beautifully- constructed spiral vessels, with several helices curiously and regularly twisted within them. He wonders to find such vascular cells in a plant which presents no indications of leaves or stem. On closer examination, he finds that the INTRODUCTION TO CRYPTOGAMIC BOTANY. 17 dustlike bodies are regular globose cells; a few of these are placed on damp glass, they germinate readily, protruding a single thread. He perceives then, notwithstanding the spiral Fig. 7. a. Spherozosma elegans, Cord. Eng. Bot. t. 2939. b, Amphitetras antediluviana, Ehrb. Ralfs in Ann. of Nat. Hist., vol. xi., p. 276, tab. 8, fig. 5. cells, that he has before him at least one characteristic feature of Cryptogamic plants, and he is satisfied that he has again fallen on an exceptional case. He has got a Fungus of the Genus Z'richia. c. A green slimy matter in a little pool upon the neighbouring heath attracts his notice. This also he sub- mits to his microscope, and sees that it is a production of astonishing beauty, consisting of many couples of curiously pinnatifid joints. (Fig.7, a.) On examination, he is sure that increase does not take place at the tips, but from the division of the component joints. The plant is not then acrogenous, but it is so completely cellular, that without knowing ex- actly what the fruit is, he concludes at once that he has got a Cryptogam, and a further knowledge of closely allied forms will convince him that he has been correct in his apprehension. He has found some difficulty in every case, but he has found it still more impossible to suppose that he had anything to do with Phenogams. d. Soon however he is still more perplexed. The leaves which lie in the low waterspout of his conser- vatory are covered with a dark red coating. This also is submitted to the microscope, and he has wonders enough before him. Here are globes filled with uniform matter, the endochrome or protoplasm so common in vegetable cells; others, in which the protoplasm has parted into a definite num- 2 18 INTRODUCTION TO CRYPTOGAMIC BOTANY. ber of bodies, always multiples of four when he is able to count them, except when in a state of transition ; these bodies at length separate, and to his astonishment he sees them of different sizes moving about with great rapidity by means of two long slender appendages. The motion at length ceases, and the bodies soon swell and repeat the same phases. (Figs. 8, 9.) Fig. 8. Fig. 8, a. Protococcus pluvialis, Flotow, immersed in water after having been perfectly dry, magnified. b. Ditto, with the endochrome divided into two. ¢. Ditto, divided into four, the central nucleus red, the border green. d. Separate spore, with two flagelliform processes. Fig. 9, e. Cell containing eight scarlet spores. f. Ditto containing numerous green spores. g. Ditto with a scarlet spore in its cavity, furnished with flagelliform processes. h. Two spores, green below, scarlet above, all more or less magnified. From Colin Nachtrige zur Naturgeschichte des Protococcus pluvialis, Flotow. His difficulty now is to say whether he has an animal or vegetable before him. e. But a very few days previously he had found in the neighbouring water tub a mass of green threads,* of which he has ascertained the purely cellular structure, the acrogenous growth, and finally, the formation of spores from some of the joints ; and these, when free, he has seen moving about by means of a little coronet of filaments, and then, like his red globules, subsiding into rest, and germi- nating by a single thread which soon acquired joints, and was a complete reproduction of the parent filament. He is then satis- fied that his red globules also belong to the vegetable world, though exhibiting certaim attributes usually supposed to belong * Olothrix mucosa, Thuret. INTRODUCTION TO CRYPTOGAMIC BOTANY. 19 exclusively to animals, He concludes, therefore, that he must not expect the whole of the definition to answer, and is content if he can find one point at least which leaves him in no doubt. 10. All these cases were more or less exceptional, but he finds others which present far less difficulty, none perhaps which do not present some, and he soon perceives that there is a com- mon band which binds the whole, however different the parts may be, and, as he gets to subordinate divisions his difficulties rapidly diminish. The number of points of agreement, that is, will increase, while those of difference decrease, though he will scarcely find one production which does not in some par- ticular depart from the terms of any definition which can comprise the whole. Few students would, however, have worked this out for themselves. The confusion would have seemed so inextricable, that they might well have given up the matter in despair, and yet, if the caution be once well understood, that we are not to look for mathematical pre- cision or for characters which can, without failure, include every form in groups manifestly bound by some common tie, there is no more difficulty than would be found in any definition of Phzenogams taken from characters which are not universal. All Cryptogams are reproduced by spores, and all Phanogams by seed ; in one (as a general rule) there is no embryo, in the other an embryo always exists; and yet, if germination by means of a protruded filament be the essence of a spore, there are many Cryptogams which will not come under the definition. Meanwhile, however, he will have found interest increase with the examination of the new world to which the microscope has introduced him, and he will not be long before he sees that the interest does not cease with the mere ascertainment of the structures before him, but that a vast field of physiological wonder is opened to his view. 11. And here the great importance of Cryptogamic Botany forces itself upon us. It has often, indeed, been objected, that so much credit is not to be obtained in the pursuit of this branch of botany as in the investigation of the more highly organised vegetables ; and some of the first Cryptogamists of our day have felt this so strongly, that they have even been in 9% 20 INTRODUCTION TO CRYPTOGAMIC BOTANY. a great measure diverted from their original pursuits by such a notion. J am convinced, however, that it is altogether groundless ; few names are more honoured than those of Hedwig, Persoon,* and Agardh, and it would be easy to point out, if it were not invidious, numerous names which hold a primal rank amongst botanists exclusively on account of inves- tigation in Cryptogamic Botany; added to which, some of the more honoured Phaznogamists owe quite as large a portion of their fame to their cryptogamic observations as to those in the higher classes of vegetables. Numerous, for example, as the services of Sir W. J. Hooker have been amongst Phenogams, and it is difficult to appreciate them at their full value, there can be no doubt that his reputation as a botanist will rest. quite as much upon his British Jungermannic and Musci Exotici,f as any of his other very numerous publications, not to mention his direct services to science and commerce in his unparalleled exertions at Kew. That a great number of cryp- togamic botanists should be held in little esteem, by reason of confined views and uninstructed minds, is no more surprising than that there should be hosts of phenogamic botanists whose names are scarcely known, except to those who have the misery of being forced to consult their works, which might, indeed, with incalculable advantage to science, be overlooked altogether; and amongst such must inevitably be reckoned numerous writers of the present century, who are daily adding bad or spurious species to the overwhelming mass of ill-defined matter already existing; who not only have no enlarged views of the science they profess, but are at the same time destitute of the will to investigate, for they are not without the gift of diligence, the main object being to make a fair show in the flesh by the multitude of species * Persoon’s fair title to a place amongst the Principes rests upon his Synopsis Fungorum, the first successful attempt after the rise of the Linnean nomenclature to arrange the species of Fungi in a systematic form. He was the first describer, indeed, of a multitude of species, but his fame does not rest on this part of his labours, and his latest work scarcely bears out the reputation derived from the Synopsis. f Ofall his works, this is perhaps the most beautiful. The figures have scarcely been surpassed in truth and elegance, INTRODUCTION TO CRYPTOGAMIC BOTANY. 21 bearing their own agnomen. Indeed, with the meagre mate- rials which too often fall to the share of such botanists, it is impossible but that, without enlarged views, they should fall into continual error. If for example a single specimen of each form should be selected from the noble series now at Kew, made with a view to the illustration of the Flora of Tasmania, consisting of several hundred individuals of par- ticular species, it would be almost impossible, without much enlargement of mental vision in addition to great nicety of tact, to avoid making some twenty species of what to a person with all the materials before him are evidently one and the same,* and this is far more applicable to cryptogamic plants, where it is often quite impossible to frame a specific character from outward form sufficiently comprehensive, but where, on the contrary, characters drawn up from individual specimens, might seem to indicate good species. Take, for instance, almost any widely diffused species of fern, and it will be well if generic cha- racters as well as specific are not at fault. But a more fitting place for the discussion of such variation will occur hereafter. 12. Having made these observations to meet the suscepti- bility of any who may be inclined to think that cryptogamic botanists are less honoured than is meet, or the prejudices of stu- dents who might, in consequence of such a thought, be deterred from a most interesting and important branch of study, I proceed to show the real objects which lie before the Cryptogamist ; meanwhile premising, that he can scarcely hope to derive all the profit which is possible, unless he be tolerably well versed in the structure and physiology of the higher plants. At the same time, though his attention may be more especially directed to one particular branch of Cryptogams, if he wishes to work with any certainty, or to arrive at any permanent results, he should by no means neglect altogether other branches. * I speak of this from personal knowledge, having been kindly allowed to select a complete set for an eminent Swedish botanist. It was at once manifest what inextricable confusion must arise if the Flora were attempted to be worked up from scanty materials. Not only would mere forms be erected into species, but each form would give rise to nearly as many species, in some instances, as there were individual specimens, ' 22, INTRODUCTION TO CRYPTOGAMIC BOTANY. 18. I shall not dwell upon the extreme and manifold interest of the several objects which come within the view of the Cryptogamist. If variety and delicacy of structure, beauty of form and colour, and the nicest transitions from group to group, from genus to genus, besides a host of curious questions of physiology and adaptation of means to particular ends, are worthy to engage attention, Cryptogams most surely will not be amongst the most unprofitable objects of study. There will be scope, too, for the acutest powers of thought and observation, unless he is content merely to skim the surface of things Even independently of the necessity of using optical instruments, a point often much exaggerated, for if the minuter points of physiology in Phenogams are deeply studied, no less an amplifying power is necessary, and perhaps even greater tact and skill in manipulation, the difficulties which arise from the wide limits within which not merely species but accredited genera are capable of varying, are sufficient to exercise the highest mental qualifi- cations. It does not follow, however, that the end ob- tained should be at all proportional to the necessary labour. The objects which the accomplished Cryptogamist has in view, are not comprised within the mere determination of species or the admiration of the exquisite forms and comhi- nation which meet him at every turn. If he aims at nothing higher than the first, he may indeed be useful in his genera- tion, provided he be cautious enough, and possessed of sufficient self-denial to prevent his striving to glorify himself, rather than to clear the road for investigators of higher pretensions. If beauty of form and singularity of structure be alone his object, his time may be passed agreeably enough, but in most cases, like ten thousand microscopists of the present day, he will be but a mere trifler, without any better aim than innocent amusement; or if he be a dabbler in science, with some wish to attain a reputation which he has not the patience to seek after by a continued course of study and mental discipline, he will be deriving general inferences from isolated half-understood facts to the detriment and confusion of real science. Perhaps, of all literary dissipation, the desultory INTRODUCTION TO CRYPTOGAMIC BOTANY. 23 = observations of the mere microscopist are the most delusive, And even where the objects are higher, it is well that every one whose attention is much directed to this greatly abused instrument, should remember that if he wishes to penetrate the secrets of nature he must look beyond his microscope, a fact of which some microscopists of considerable reputation do not seem at all aware.* The paramount importance of the subject is to be seen in far different matters. 14, The first great point is that the physiologist is able, in the simpler Cryptogams, to study the several organs of which the higher vegetables are composed, isolated and altogether removed from other structures which may impede the view, or by their rupture cause confusion. If, for instance, it is desired to ascertain the mode of growth in cells, he will be able to appeal to the simpler Algee, whether grumous or filamentous, In the one he will be able to trace step by step the division of the pri- nitive mother cell, with nothing to prevent his view in consequence of the great transparency of the walls; or if he take one of the simple or branched Conferve, he will be able to assist at the origination not merely of two new cells from the subdivision of one, but the formation of a new cell by pullulation from the walls. Meanwhile he can ascertain exactly what changes the endochrome is undergoing, he can watch the part which the cytoblast bears in the process, and can sometimes trace its parti- tion. He can investigate in many cases, as in Zygnema and its allies, or much more in Chara and Nitella, the currents which traverse the length and breadth of the cells; he can tracethicken- ing of the walls by the deposit of new coats, and in some cases the shelling off of those which are effoete and have performed their office. He can observe, moreover, the wonderful union of separate filaments, the formation of a vital spore from the union of the contents of neighbouring cells, and many other points of interest, which throw more or less light on the * T allude here especially (amongst many like instances) to the utter indifference with which Mr. Thwaites’ great discovery of the conjugation of Diatomacee was received at the Oxford meeting of the British Asso- ciation, by one whose whole reputation was built on the microscopic study of these and other analogous organisms. 24 INTRODUCTION TO CRYPTOGAMIC BOTANY. processes which occupy the attention of the investigator of the vital processes of the higher vegetables. Amongst the lowest vegetables he will find many facts which will give him points of comparison with inmates of the animal kingdom ; he will see apparent Infusoria existing as mere vegetable organs, and will find them performing functions under a form which he will in vain hunt for amongst the higher vegetables, and if his attention be turned to those Cryptogams which more closely resemble these in outward appearance, he will find a form of spermatozoid so closely resembling the impregnatory bodies of the higher animals, as to open his mind more strongly than ever to a conviction of the intimate bond by which all the members of the organised world are bound, though he may not subscribe to those theories which deny the existence of definite groups. There can be no question in these cases of the spermatozoids being developed in perfect freedom within the mother cells, and not mere appendages separated from their walls, and endowed with a vital action, similar to that of the cilia, so common to mucous surfaces, as many animal physiolo- gists assert. Such investigations will come in aid then of those relative to the development of spermatozoa in animals, and similar advantages will be presented in many other instances,* and consequently the cryptogamic student will be able to form more exact notions as to vital action in the animal and vegetable kingdoms, than are usually held by those who confine their investigations to either division of the organised world. Again, though spiral vessels are compara- tively rare in Cryptogams, opportunities of studying their development and. nature are nowhere more available than amongst the Hepatice,+ where they occur without the inter- vention or attachment of any other tissue, while in Zygnema the curious and multiplied spiral bands may with ease be traced from the first formation of the cells in which they are developed. 15. There is another point of immense importance, which the cryptogamic observer has in a peculiar degree the power of stu- * Martino in Ann. d. Sc. Nat., sér. iil, vol. 5, p. 171, on the deve- lopment of Spermatozoa in the Skate. f See Henfrey Linn. Tr., vol. 21, p. 103. INTRODUCTION TO CRYPTOGAMIC BOTANY. 25 dying successfully. Questions often arise as to the point whether cellular structure can originate without the presence of aprevious mother cell. It is a question, for instance, whether cells are ever formed in Phenogams from mere organisable sap, as presumed by Mirbel in his paper on the Date Palm ;* or again, whether, in what is called organisable lymph in the animal world, cells can originate freely without pullulation from neighbouring tissue with which the lymph is in contact. In the blood, once more, are blood globules, or in unhealthy conditions pus globules, ever formed simply from the consti- tuents of the blood itself, without the concurrence of previously formed organisms? Now in those fungi in which, as in Spheria and Peziza, the reproductive bodies are generated by the endochrome of the fructifying cells, the Cryptogamist has the power of watching the development of the spores from the very moment when the endochrome commences to be organised, and he can with confidence assert that they are not the creatures of previously-existing cells, but the produce of the endochrome itself, He will be able to compare with this what takes place in the embryo sac of Phenogams, and will be better prepared to appreciate all the arguments which bear upon the Schleidenian Theory of the formation of the embryo. Both the formation of the albumen and of the embryo itself will then be studied with greater zest, and he will certainly, after watching the origin of spores within an ascus, be able to judge better of what takes place or does not take place within the pollen tube. It is true that many of the points I have © Fig. 10. Gleocapsa rupestris, Kiitz, magnified, from specimens communicated by M. Brébisson, from Falaise. The simple spore has first given rise to two new spores, and then to four. * Ann. d. Se. Nat. Sér, 2 vol. xi. p. 321. 26 INTRODUCTION ‘lO CRYPTOGAMIC BOTANY. mentioned may be examined profitably in Phenogams, but always with more difficulty, and seldom with such precision or with such satisfaction and conviction to the observer, and there is one point which must always be borne in mind, that the objects in question grow and are developed under his eyes, if he possesses proper powers of manipulation, which will scarcely ever be the case with Phenogams, if the parts be freed ever so neatly from the surrounding tissues* Nay, the examination of the developement of cells in such genera as Hamatococcus and Glwocapsa (Fig. 10) will help even the Zoologist, for no- thing can be more close than the mode of development in these, and of the vitellus in the eggs of certain Mollusca (Figs. 11, 12). b Fig. 11. Eggs of Acteon viridis in different stages. a, Ege, showing the vitellus still simple. b. Ege, with four celled vitellus. c. The vitellus divided into two. d, Ditto into four, From Vogt Recherches sur l’"Embryogénie des Mollusques Gasteropodes, Ann. d. Se, Nat., sér. iii, vol. 6, p. 1. The bodies, indeed, which are so much alike, or in other words are homologous, identical, that is, in structure and genesis, though not in function, may not always be of equal * Most eminent vegetable Physiologists have been more or less Cryptogamists. One of the earliest studies of Mr. R. Brown was Schmidel’s Icones, a work which anticipates many modern observations, as the spiral structure of the threads in 7richia, and the motion of the Spermatozoids in Jungermannia, and one of the best memoirs on the development of the embryo in vegetables, is that of Tulasne. INTRODUCTION TO CRYPTOGAMIC BOTANY. 27 value ; but the student will learn as much, perhaps, from the observance of their differences, as if they were in every respect perfectly accordant. 16. There is another point which makes the study of cryptogamic botany peculiarly interesting, viz.:—because so large a portion of fossil vegetation is so intimately related to some of the nobler Cryptogams, and possibly exhibits far grander and more highly organised individuals than ‘any which at the present era occur in a living state. It is for- tunate that these, in some cases, still retain their spores in such a perfect condition, as to admit of accurate appreciation. In some fossil fruits,* indeed, which have certain primd facie u. b. c. Eggs of Aplysia depilans from Vanbeneden Recherches sur le dévelopement des Aplysies, in Ann. d. Sc. Nat., sér. ii. vol. 15, p. 123. a, Contained in thread, natural size.t b. Thread and eggs magnified, showing the quadricellular vitellus. c. Vitellus in different stages, highly magnified. d.e. Gloionema paradoxan, Ag., being in fact the eggs of some Tipula. d. Thread, with its rows of eggs magnified. e. Eggs highly magnified. See Berk, in Ann. of Nat. Hist., vol. 7, p. 449. * Carpolithes Ovulum, Brongn. and Folliculites minutulus, Bronn. Hook. fil. in proceedings of Geological Society, 1855, p. 562, 566. + This is, I believe, Ulva defracta, Eng. Bot. 28 INTRODUCTION TO CRYPTOGAMIC BOTANY. claims to admittance into the series of cryptogams, and would undoubtedly vindicate these claims, were it sure that the bodies contained in their cavity were spores, the membranous coats which line their cavity are still as flexible as they could have been in life, exhibiting every marking and peculiarity of structure with the greatest precision, and in some cases, pre- senting a double lamina capable of separation at the point of confluence, while each possesses its own cellular arrangement. It is amongst fossil plants, if anywhere, that we must look for indications of the highest perfection attainable by Crypto- gams. Meanwhile, an accurate acquaintance with the habits of those species which still exist upon the earth, and of the temperature and climate in which they flourish, may possibly afford some key to the questions which so often occur to the geologist, respecting the climate which must have existed on the earth at the time of some given geological formation, to allow of the luxuriant development of these gigan- tic forms. Nor are these the only kind of Cryptogams which abound in certain strata ; there are numerous others which are immediately and certainly comparable with existent species. Many forms occur which have no modern analogues, or are in such an altered state, as to allow of little more than con- jecture as to their affinities; and even the ferns themselves, whose form is often so beautifully preserved, so very rarely pro- duce fruit, as to lose much of the interest they would otherwise possess ; but the siliceous cases of Diatomacew are preserved in such extreme perfection, as to be as satisfactorily comparable with existent species as the remains of mollusca, and, as in those, a host of species may as safely be pronounced identical. 17. Another excellent inducement to the study of Crypto- gams is the fact that so many of the diseases, both of plants and animals, arise from their presence. The species which affect animals are probably few in number, and for the most part of common kinds, possessing great powers of ubiquity, and therefore able to establish themselves on what, from the very nature of things, cannot be their natural habitat, Though great attention has been paid to the study of such Cryptogams, as infest man, and other animals, they have seldom been INTRODUCTION TO CRYPTOGAMIC BOTANY. 29 studied by competent persons, possessed of an accurate know- ledge of species, much less of a power of appreciating the changes which may take place in the same species, according to varying outward circumstances. Those who have recorded their occurrence, or have given figures illustrative of their aspect and structure, accompanied by distinctive characters, have often been physicians better versed in anatomy and microscopy than in cryptogamic botany, and often unable to distinguish a mould from an Alga. The parasites of the vegetable world are much more numerous, and are clearly autonomous; and as some of them produce great ravages on those plants which most subserve the use of man, their study is of immense economical value, apart from other less utilitarian considerations. Till these parasites are accurately distinguished from each other, all attempts at remedy must be empirical ; and thus, in the case of the diseases which affect the hop, no efficient remedy was even attempted till the nature of the two principal diseases with which the plant is affected, known under a multitude of names, was accurately ascertained.* 18. No student of these lower vegetables, then, need blush for his choice. His wisdom plainly is not to confine his views within a narrow prescribed limit, and above all, not to the mere study of species, though that alone is far more im- perative than numbers of pseudo-physiologists will allow. Without it, the results of his observations can scarcely be conveyed with certainty to others, and their field will be greatly circumscribed. The study of species in itself is of great utility, if conducted on broad and sensible grounds. If he takes a wide view of things, he will be sure in the course of his investi- gation to throw much light even on points which, perhaps, in the first instance, he might least think of being able to illustrate. 19. Nor will a few words on this subject of species be com- pletely out of place, though we have incidentally touched on it before. It is one which the cryptogamic student will meet with at every turn. It is a common opinion that cryptogamic species are so variable, that it is impossible to circumscribe them with specific characters; and, to be studied with certainty, * Berk. in Gard. Chron. 1849, p. 467. 30 INTRODUCTION TO CRYPTOGAMIC. BOTANY. they must be studied in the herbarium. The practised eye will there detect similitudes between widely different forms which no definition could convey. Now there is certainly much truth in this notion, but more perhaps, from the wrong concep- tion of authors than from the intrinsic difficulty of the case. So long as essential characters are neglected, and fleeting external characters put in their place, difficulty must needs exist, and the student will never be certain that he has come to a correct decision till he has seen an authentic specimen, or compared his own decision with that of other botanists as manifested in extensive herbariums. A state of uncertainty is always one of more or less pain, and the temptation to a solution of the difficulty by the supposition that he has made some new discovery, will often present such attractions as to prove insur- mountable. Nor will he find it possible, without that mental discipline which arises from a patient study of every detail of structure, and of the various shapes which organs may assume under different circumstances. Without such discipline, like certain German authors of some repute amongst persons unin- structed in the subjects they profess to handle, he will propose a new name for every difference, even suchas are manifestly merely temporal and accidental, and, on the contrary, he will unite whole groups which belong to entirely different categories. It would be easy to point out glaring examples, both amongst algologists and mycologists. One of the worst amongst Phe- nogamists, perhaps, is the erection of that state of the inflores- cence of several species of Cissus, in which the peduncles are deformed by the presence of an internal parasite (Puccinia incarcerata, Lév.), into a distinct genus of Phenogams ; though this is not worse than referring the same Alga received from different sources to two or more distinct genera, and that not among the lower or more obscure species, where there might be some excuse for such a proceeding, or the association of plants so totally different, as Puccinia and Trichotheciwm. Nor is the correct appreciation of species of so little consequence as is sometimes vainly supposed. The only way in which we can arrive at anything like accurate views of geographic botany, or the distribution of plants over the globe, is by a correct esti- INTRODUCTION TO CRYPTOGAMIC BOTANY. 31 mation of species. If two Floras be formed on different princi- ples— while in the one the species are accurately limited, and forms which vary only in some subordinate point, and not in essential characters, are grouped under one common name; in the other, not only every marked variety, but even accidental variation, is elevated to the rank of a species,—it is impossible to form any correct comparison, and this is the more necessary in Cryptogams than elsewhere, because the species have noto- riously such a wide diffusion, and because their technical, though not their essential characters, are so very variable. The great point in all these cases is never to describe from single or imperfect specimens, where there is some form evidently very closely allied. It may not be possible, perhaps, always to avoid error, but a little caution will be most advantageous, both as to one’s own individual character as a botanist, and to science in general. And if species are once accurately characterised, there will be far less difficulty than may be imagined as to genera. Nothing is more vain than to run down botanists as mere makers of species, as though it did not take as much knowledge and tact to limit species well, as to ascertain a few detached microscopical facts without deriving any general views from such study, or ever seeing the relative bearing of such observations. The physiologists of the present day, at least too many who have some name in science, are absolutely doing the very thing which they profess to despise in species- makers. A proposer of bad, ill-defined species is no promoter of science; still less is the so-called physiologist who draws from isolated half-observed facts, conclusions which the very next observation may entirely destroy. We may regret, indeed, sometimes the over-caution of the prince of physio- logists, but such over-caution is ten thousand fold more praiseworthy, and tends more to the advancement of science, than crude, hasty, and ill-considered theories founded on imper- fect observations, because what it does bring forth is essentially & xrnpa ec ae, and, even when incomplete, is a sure step- ping stone for the acquirement of some further eminence. 20. Before entering into a more particular consideration of the different sections into which cryptogamic plants are divi- 32 INTRODUCTION TO CRYPTOGAMIC BOTANY. sible, it is necessary to consider how far they are related to phenogamic plants, and whether there is any close affinity between any particular order of the two series, which can, with very great probability, be indicated. Mere cases of analogy have little weight in such a consideration. Such cases are presented by the three natural orders, Balanophoracee, Cytin- acee, and Rafflesiacec, on the one hand, and by Podostemacew on the other. In the latter case, there is a great want of spiral vessels, and the forms of many Cryptogams are curiously represented, but there is nothing about the fructifying organs to cause the least perplexity, and the best opinion is that they are reduced Lentibularic.* The foliaceous expansion is of little consequence. All such productions are mere offsets from the axis, whether horizontal or vertical, which are often dis- pensed with altogether, insomuch that, as regards a question of this kind, the Schleidenian doctrine, that “plants have no leaves,” is perfectly true.t The Rhizanthous order mentioned above, in habit, parasitic mode of growth, and substance, bears a close resemblance to Fungi. If, for instance, a Pilostyles be compared with such Fungi as Podisoma and Cyttaria, which grow upon living branches of Juniper and Evergeen Birch, producing a new crop year by year from the old mycelium, there is a striking resemblance in the way in which the indi- viduals are dotted over the stem. In the fungus, however, there is not a doubt that the threads of the mycelium penetrate the cells of the matrix, and burst forth in the shape of new individuals. Mr. Brown failed to prove that this was the case in Pilostyles ;{ but even supposing that he had been able to show that the rhizoma crept under the bark, and pro- * Willdenow referred two genera toCryptogams, Blandovia=Apinagia, and Dufourea=Tristicha, the former to Hepatice, the latter to Ferns. Mag. der Ges. Nat. Freunde, zu Berlin, vol. iii. p. 200, and vol. vi. p. 63. { Such expansions may or may not have vascular tissue. In the former case, they would be mere offsets from the bark. It is obvious that the possible or actual formation of a bud in the axil of each leaf, is favored by the presence of vascular tissue. t When Mr. Brown was preparing his memoir for the Linnxan Transactions, he was so kind as to show me his specimens, and to have some conversation on the analogous points in Podisoma. His observa- INTRODUCTION TO CRYPTOGAMIC BOTANY. 33 truded new buds, their development would be little more than what takes place in those phenogamous plants, in which ad- ventitious buds are formed from the roots; and I have some- times thought that I have been able to trace the same thing in the common Misletoe, as to the affinities of which there can be no question. If it could be proved that such genera give out a true mycelium, consisting of distinct mucedinous threads, uniting at length in more or less solid cords or expansions, and then, without the neighbourhood of any spiral vessels, throw- ing up flowering buds, it might at once be pronounced that we have a very close approximation to a cryptogamic type. But this is not the case. Spiral vessels may be few, but there are Phenogams of very different aspects and affinities, in which they are equally or more deficient. When the flowers are examined, we find a regular division of the perianth as in other Endogens, a distinct pistil and anthers, ovules on parietal placente, and a distinct embryo* not more minute than in many other cases, and the division into Cotyledons not more obscure than in some other parasitic genera, which have evident connection with other plants which bear no relation to Cryptogams. In Cytinus and its allies, we have nearly the same condition of matters. That the seeds should be buried in pulp after a time is no indication of inferiority. The true disposition of these organs can, in many cases, be discovered only in the earlier state of the germen. In the case of Balan- ophoree, though we have still a great analogy to Fungi, the moment the substance of any part is divided, all doubt as to any affinity ceases ; and if the stems and their connection with the matrix be examined we are at once convinced that we have no such type before us. A certain similarity of colour, and the absence of green tints, in addition to the habit, give a fungal tion that plants of the same sex, where the sexes are distinct, occur in patches on the matrix, is perfectly consistent with the view taken in the succeeding paragraph of the text. * Miers asserts that there is no embryo in Triuris, but Dr. Lindley very properly remarks that the body in question is rather an exalbu- minous embryo, than an exembryonic albumen. Compare, however, the whole of Miers’ remarks in the Vegetable kingdom under T'riwrides. 3 3+ INTRODUCTION TO CRYPTOGAMIC BOTANY. appearance to these plants; but, on the other hand, not to men- tion the total difference of the fruit, their slow growth,* and the extreme difference of texture separate them. There is, indeed, often the same volva-like dehiscence as in Geaster, something similar to which exists in Marattia. This seems, however, merely an exaggeration of what takes place constantly in the formation of adventitious buds and roots, to which it is really more nearly related, than to the more obvious resemblance of Geaster, for in that case the whole of the resemblance is con- fined to the separation and rupture of an investing cellular substance. There is no question about vascular tissue here ; the stems are not formed on an endogenous type, and the mode in which the vascular tissue of the shoot originates, as compared with that of the matrix, is precisely that of adven- titious buds as compared with the especial portion of the vas- cular system to which they belong. In this case, the vascular tissue of the matrix appears to exercise the same influence as it would do if the branch was merely a shoot from itself+ It is very true that the floral envelopes resemble closely those in some Hepatice, a circumstance which occurs also in Podos- temacece; this certainly is of such a nature as to prevent our saying that Cryptogams are always destitute of such envelopes, but it does not show the slightest affinity. The presence of para- physes undoubtedly affords another point of resemblance, but this is of no great consequence, as analogous bodies exist in many cases of crowded inflorescence. I cannot perceive any essential resemblance between the ovaries and pistillidia of mosses. The pistillidia of mosses, in fact, reasoning from the structure of Club-mosses, if they can be said to be homologous at all, which I do not think to be the case, are not homologues of the ovary, but of the embryonic cavities or corpuscles of Conifers, and therefore must be mere analogues of the ovaries * Ombrophytum, however, is said by Peppig to spring up suddenly after rain, and is eaten like Mushrooms. Hook. fil. in Lindl. Veg. King., p. 90. + Similar observations have been made in Orobanche. The memoir on Balanaphore lately read by Dr. Hooker before the Linnean Society must be consulted on this subject. INTRODUCTION TO CRYPTOGAMIC BOTANY, 35 of Balanophore. Our information at present, with respect to all of these plants, is very imperfect, but it may be asserted, without fear of contradiction, that the better we become ac- quainted with them, the more distinctly their want of affinity to Fungi comes out. 21. Such genera again as Lemna, at first sight, may seem to have some claims to relationship, and indeed the species are included amongst the Plantes Cryptogames du Nord of M. Des- maziéres ;* but as every plant in the first instance is destitute of vessels, and myriads of perfect embryos, we can lay little stress upon this point, when the indications of the fruit are as dis- tinctive as in any other genus. And in point of fact, spiral vessels occur abundantly in Lemna polyrrhiza. The resem- blance between Lemna and Riccia is entirely confined to the foliage, and the mere fact that one may be taken for the other, is only one of those curious instances of analogy which present themselves in every part of the vegetable kingdom. A super- ficial glance is often at fault, when the slightest examination of structure at once sets aside all doubts. Other aquatic En- dogens might perhaps be mentioned, but their resemblance is far more slight, and their want of relation still more evident. 22. We now come to a very important subject, the supposed relation between Conifere with other Gymnogens, and some of the higher Cryptogams. These views are, I believe, as un- founded as those which have been stated above, and instead of giving a deeper and larger insight into real affinities, as is sometimes supposed, they tend, as I conceive, rather to con- tract the mind in a general view of the vegetable world. Nature does not make sudden leaps, and though in plants of very different affinities points of resemblance may exist, they are not to be estimated at more than their proper value. There is no single point at which the two great circles of the relations severally of Phanogams and Cryptogams can be con- sidered as so perfectly coinciding as to intimate any marked transition from one class to the other. Individual points of resemblance may be discerned, but such as to show no close * He did not, however, intend to intimate any affinity between these plants and Cryptogams. 3 * 36 INTRODUCTION TO CRYPTOGAMIC BOTANY. relation, nor such as in any morphological view of the origin- ation of one set of beings from another could at once indicate the possibility of change; as for example, from a cup-shaped to a mitreform fungus of very close affinities, by the mere re- troversion of the cup, and the consequent confluence of its under side with the stem. (Fig. 13.) Fig. 13. a. Helvella Esculenta, from a British specimen communicated by Mr. Frederick Currey. b. Helvella elastica. ce. Peziza macropus. 23. Except in the depauperation of the floral envelopes, a point evidently of little comparative importance, since we see that the nobler objects of the vegetable world are most fre- quently those whose floral envelopes are the least developed, it would be difficult to point out one single particular in which Conifers are inferior to other arboreous Exogens. The very slow development of the fruit should, on the contrary, seem to indicate superior dignity. It may be true, indeed, that spiral vessels are comparatively rare in the trunk, but then the presence of these in abundance is no sure evidence of superiority, and even admitting their infrequency to be a mark of inferiority, the wood cells are more complicated INTRODUCTION TO CRYPTOGAMIC BOTANY. 37 than in many other plants.* But though spiral vessels are comparatively unfrequent in the aerial portions, the little pro- cesses which terminate the roots in very many species as first observed by Dr.,Hooker, and, indeed, where no such swellings appear, the external cells of the rootlets abound in spirals very much after the fashion of those which are so conspicuous In the aerial roots of Orchids That such tissue, when young, is very active, there can be no doubt, but after a time, it merely contains air, and sometimes, as in Trichiu and Hepaticw, an- swers the subordinate purpose of opening and closing the peridia by mere elasticity. And it is possible that some secondary end, as the securing a channel for the passage of air under strong pressure, may be answered even in plants of the firmest struc- ture, in which the yielding of such tubes, and their return to their former calibre, may be of consequence. Some purpose of this kind is certainly effected by the tracheze of insects, which are so like to spiral vessels in appearance, as to suggest some similarity of function. The functions, however, of spiral vessels in vegetables are so obscure, that we can deduce little from their presence or absence. They cannot be in themselves in- dispensable, or such enormous trunks as are presented by some Conifers could not exist ; and whatever their function may be, * A spiral structure is very visible in the wood cells of the Yew, and, as mentioned above (p. 8), in the white Spruce drift wood of the Arctic Regions. Dr. Hooker has shewn that the close tissue produced at the end of the year is eminently spiral, while the peculiar pine tissue is produced only when vegetation is in full vigour, intimating the latter to be more perfect than the former. See also Berendt Org. Reste im Bernstein, tab. 2, fig. 7, 12. t Specimens of roots of Daerydium and other Conifers have been long since sent from Australia and New Zealand, laden with these pro- cesses. The specimens were sent as parasitic Fungi, but a very slight examination was sufficient to shew that they were really part and parcel of the root. Dr. Hooker's attention was drawn to them acci- dentally, and he communicated to me his observations on their structure, which I was able completely to confirm. Afterwards we found similar bodies on most of the Conifers cultivated at Kew. I have lately ascer- tained that the structure is figured in Hartig Lehrbuch der Pflanzen- kunde, tab. 18, a work which is apparently in very few hands in this country. 38 INTRODUCTION TO CRYPTOGAMIC BOTANY. their absence may be compensated by large intercellular aper- tures, and there is no reason why the same or similar ends, produced by more simple means, if perfectly accomplished and productive of as important results, should be entitled to less dignity than more complicated processes. We see at once that a heart consisting of one auricle or ventricle is inferior to one presenting two, but then the ends to be accomplished in the latter case could not be accomplished by the simpler means, and we have nothing to show that the trunk of a Conifer is in any respect inferior to that of any other Phenogam. The production of a multitude of embryos in the same embryo-sac, again, is scarcely comparable with the analogous phenomenon in animals, for in vegetables some that have the highest dignity are the most productive ; the multiplicity, therefore, of embryos is rather to be considered as a mark of perfection, especially when it is remembered, that the seeds of Conifers are as perfectly formed as those of any other phenogamous plant. Where there is some external form upon which to build a comparison, as in Club-mosses, and the large fossil Lepi- dostrobt, there is such an utter want of accordance between the mode in which certain similar effects are attained, that there is, as it seems to me, no question as to affinity. 24, It is desirable, before entering further on the argument, to say a few words on one or two points which are necessary to its perfect apprehension: and the more so, because the view I take is not that of some of the highest botanical authorities, much less of those who have had no opportunity of studying the matter deeply, and are, therefore, likely to be fascinated with the specious arguments and outward resemblances which, at first sight, may seem to indicate that the relation between Pheenogams and Cryptogams is far greater than I am myself able to allow. I shall endeavour to explain my view as simply as I can, and with as little use of technical language. Without some previous knowledge of vegetable physiology, it is not very easy, however, to see the true bearings of the question. 25. It will, in the first place, be useful to the student to illus- trate, in a simple manner, the terms analogy, homology, and affinity, as they are necessarily used very often, and as fre- INTRODUCTION TO CRYPTOGAMIC BOTANY. 39 quently confounded by the student. Analogy, in the first place, indicates certain resemblances between things, whether similar or dissimilar in nature. A large portion of poetical images are derived from such resemblances. These may be more or less remote. The old Pythagorean notion, for instance, that an egg is a microcosm representative of the earth, in which the shell answers to the earth, the white to water, the yolk to fire, and the bubble of air at the end to the atmosphere, is a case of very remote analogy. The notion, again, of the elder Agardh that a bird is an analogue of the world (like it, it moves freely through space ; the feathers are the trees which grow out of it, and the parasites amongst the feathers the animals which move amongst the trees), is a case of rather closer analogy than the former, but still very remote and fanciful. There is not a particle of affinity, of course, in either case. Analogy, however, may exist between things which have a closer relation to each other The wings of an insect, for instance, have a certain resemblance to the wings of a bird; their function is the same, but they are not modifi- cations of the same organ.* The trachez of insects, again, have the same function, in all probability, as the spiral vas- cular tissue of plants ; but they can scarcely be said to be the same organ. The fovilla of the pollen tubes of Phenogams has the same function as the spermatozoids of Cryptogams, but they are not the same organ. These, then, are so many cases of likeness of function, without any similarity of origin or essence, and they are, therefore, cases of analogy, and the objects themselves are called analogues of each other. There are likenesses, too, where there is neither identity of origin nor function. Such likenesses may be general resemblances, as that of certain galls to Fungi. The one are sometimes exact counterparts of the other, but the resemblance begins and ends there, and leads to no important conclusions. Exactly in the same way there may be two extensive genera, not in the least * The palpi of spiders have, in all probability, the same general functions with those of insects, but there is a generative function superadded. In one sense, then, they are homologues, in another, analogues. 40 INTRODUCTION TO CRYPTOGAMIC BOTANY. related to each other, in which striking resemblances may exist between certain species of two or more series. Such resem- blances may be purely accidental, or they may be part of that harmony of the works of Creation, in which certain likenesses seem to blend the most dissimilar organisms into one connected mass ; “a mighty maze! but not without a plan.” No one sup- poses, for instance, that there is any relation between those twig- like caterpillars which deceive their enemies, or the leaf-like wings of the Mantis, and the objects which they resemble. These examples are, in a lower sense, cases of analogy; but, in a higher sense, we understand by analogy those cases in which organs have identity of function, but not identity of essence or origin. 26. In deeply studying the relations of organised beings, it is necessary to study the changes which the same organ under- goes in different individuals. Such considerations constitute what is called morphology. The organ itself may, evidently be the same, and yet the functions of it may be wholly different. If, for instance, we study the mode in which pollen grains are developed within the mother-cells, and compare it with the development of the spores in the higher Cryptogams, there cannot be a doubt that the organs are similar in origin, though the functions are totally different. The spores germinate in precisely the same manner as the pollen grains, and, in some cases, from definite points; the end of this germination is, how- ever, totally different ; in one case it is the growth of the new individual, in the other case the impregnation of a cell. Such bodies, then, are homologous ; they are identical in essence and origin, but dissimilar in function.* The spores of the Cryptogam, on the other hand, and the seed of a Phanogam, have, to a certain extent, the same function, but they have no resemblance of essence or origin; they are, therefore, analogous, and not homologous. These distinctions, when once fairly grasped, are of immense importance in estimating the rela- * The primary spores of such parasitic Fungi as are represented, fig. 6, originate in a totally different way from the spores of the higher Cryptogams, and though they germinate at definite points, can be only considered ag analogues of pollen grains. INTRODUCTION TO CRYPTOGAMIC BOTANY. 41 tions of organised beings; and we may, therefore, define analogy to be resemblance of function; homology, corres- pondence of structure or origin.* 27. The word homology, it will be seen then, is more confined in its use than analogy; for we can scarcely limit the latter word within the bounds just prescribed, except where it is the correla- tive of homology. Homology relates, for the most part, to organs; analogy to organs and to organisms. Now resemblances of very different kinds may exist between such organisms. They may be similar to each other in many respects, and yet there may be no positive relationship between them. Organs may be homologous with perfect organisms, as the tissues of plants with some of the lower Cryptogams ; but there can be only remote affinity be- tween them. There can be no intimate affinity where the one class, order, or species, does not approach, in nature, close to an- other; there must be an identity in the most essential characters, or such a gradual melting of the one into the other, as makes it difficult to say where the distinction ends and begins. Lichens, for instance, so gradually pass into fungi, that it is almost im- possible to say to which division certain species belong. In such a case it would be foolish to deny that there is a very close re- lationship. The resemblance is not one of mere analogy. On the other hand, though there is an intimate homology, up to a certain point, between the several organs of which a lily is composed, and a water lily, there is no affinity between them, except so far as they are both members of the Phenogamic class. There is homology + of organs; there is analogy in the one plant, as a whole, compared with the other, but there is no affinity. These principles will be found of great conse- quence in the comparison which we shall shortly have to institute between certain Cryptogams and Pheenogams, 28, Analogy, then, indicates resemblance between objects which have not necessarily any close affinity; such resemblance may be of greater or less importance, but it is always lable * See Carpenter’s Principles of Comparative Physiology, Ed. 4, p. 6. + Perhaps the nearest synonym to homologous is correspondent. But as bodies may correspond, both in function and structure, it is obvious that the word is not sufficient. 42 INTRODUCTION TO CRYPTOGAMIC BOTANY. to seduce an inattentive or ignorant observer into wrong notions as to the relation of the beings between which it exists. Resemblances of this kind were, at one time, carried to such a point by the Okenists and other German philo- sophical naturalists, as to involve everything in a cloud of mystical obscurity, like that in which divinity is shrouded by the Hutchinsonians. Homology is of far more value ; for when true it is founded on a deep knowledge of structure, and is indicative either of close or remote relation, while analogy does not necessarily indicate either the one or the other. Affinity expresses the fact that organisms are related, and is of various kinds ; it may be no more than that between one being and another simply as organisms, between the members of distinct divisions, or between those divisions themselves: but when one being, or class of beings, is said to be allied to another, it is generally meant that the peculiarities by which one is distinguished pass gradually into those of the other. It ex- presses immediate relationship and not remote connection. 29. An excellent view of the relations of analogy and affinity has been intimated to me in writing by Dr. Hooker. He says, that the difference between analogy and affinity depends mainly on affinity being betrayed by attributes which are as prominent at the earliest period of growth as at the latest, and often more so; but the contrary holds good of analogy. Thus the hairs of the capitula of Balanophore, and the para- physes of mosses are perfectly similar, but this circumstance shows no affinity between them, for they are modifications of what are fundamentally different organs. If the first development of the Mammalian ovum be compared with that of an Heematococcus, it will be impossible to deny the close resemblance, and that both take place on one plan. The relation, then, between the highest Mammal and the obscurest. Alga, though almost infinitely small, yet certain, is capable of being ascertained only in these first stages of development. The relations, again, of plants with central placentation to others with parietal placentee may be obscure. Not a trace of the latter structure isto be found in full-grown Cloveworts, or even where the carpels are normally developed. But a monstrous state of INTRODUCTION TO CRYPTOGAMIC BOTANY. 43 the common carnation and sweetwilliam has given at once the clue.* The ovules in this monster are replaced by carpels more or less distinct to their base, and, in this condition, the placentation is as truly marginal as in any Phenogam; and whatever affinity there may be in the matter is prominent only when the plant is reduced to its fundamental condition. In other conditions the real relations of the parts are obscured. Multitudes of similar cases might easily be brought forward in confirmation of the law. It is to be considered, moreover, that every observer differs, not only in the estimate of false affi- nities, but in the amount of likeness from which they start. Homologies, when once established, are certain, and must be estimated by every competent authority at the same value. Andrea affords an excellent example. It is a moss in every- thing except the dehiscence of the theca. There is an analogy between this and the quadrifid capsule of Jungermannia, but there the likeness begins and ends. The likeness is visible only in the last stage of growth. If it were a case of affinity it should be visible at once. There would have been a development of elaters or something homologous within the theca as in Jungermannia. 30. It is desirable, again, before entering further on this argument, to say a few words on the reproductive organs of Cryptogams, at least on the female organs, for there is little or no similarity between the male organs of Cryptogams and Phenogams. There are no proper pollen globules, no ger- minating of a cell to bring the walls in contact with the embryo- sac, nor is there any agreement between the mode of genera- tion of the grumous matter or fovilla and the spermatozoids. In the more simple cases there is nothing at all analogous to flower, but certain privileged cells are separated from the threads or compact tissue of the matrix, whether naked, or produced within a special tube or sac, and constitute the fruit. These germinate almost exactly like pollen grains, and reproduce the species. There are, sometimes, several kinds of spores upon a plant, all capable of reproduction, though differing in appear-. ance. These spores, then, are homologues of the individual cells * See Gard. Chron. 1850, p. 612 ; 1855, p. 280. 44 INTRODUCTION TO CRYPTOGAMIC BOTANY. of Phenogams, which, at times, are equally capable of re- production in the shape of buds. 31. The spores, or what have the appearance of spores, do not always reproduce the plant immediately, even in plants of such a low grade as Fungi. In the higher Fungi, certain cells swell and become clavate, producing on their surface a number of little points, each of which is terminated by a spore. In Tremella, this clavate swelling has much the appearance of fruit, but the points upon its surface are greatly elongated, and true fruit at lastis produced. In certain cases, these spores produce from their surface minute processes, supposed by Tulasne* to be male organs. These can only be seen with a nice adjustment of the light. Their existence has been verified by myself and Mr. Broome; their functions, however, at present must be considered doubtful. In the gelatinous fungus, which is so common on Juniper, Podisoma (Fig. 6a), the bodies I have represented are very like these sporophores in Tremella, but they germinate truly like other spores, and are remarkable for germinating at definite poimts. The Fig, 14. a. Germinating spores of Vephrodium marginale. b. Prothallus of Gymnogramma chrysophylla, as seen from below, shewing the antheridia and archegonia. From Henderson in Mag, of Zool. and Bot. vol. i. p. 333. * Tulasne in Ann. d. Se. Nat. Sér. 3, vol. xix. p. 193. INTRODUCTION TO CRYPTOGAMIC BOTANY. 45 threads they put out produce in fact the true fruit. This holds good equally of all the blight or rust like Fungi, such as affect corn and other living plants.* 32. A different order of things prevails amongst the higher Cryptogams. The spores germinate and produce a more or less foliaceous mass, which after impregnation bears fruit containing bodies like the original spores, or a plant capable of bearing such spores, in which case it is called a prothallus. (Fig. 14.) After a time, certain pitcher-like processes project from it, or are sunk in its substance. A cell at the base of these urns, when impregnated, grows after the fashion of the first cell of the embryo in Phenogams. In some cases, then, the cells which arise from germination are developed, as in mosses, into a plant directly, reproducing spores by which the cycle is again accomplished ; in others, as in Ferns and Club-mosses, an embryo more or less resembling those of Phenogams is first generated, which strikes root and sends out an ascending stem, which sometimes grows into an enormous tree, pro- ducing every year a crop of spores. The spores, then, in these different plants are of very different values, and in no respect homologous with the seeds of plants. Cryptogams have, in fact, no true separable seeds,though, in the highest forms which they assume, they generate an innate embryo. Without some such notion, though I am obliged to anticipate matters to be described more fully hereafter, it is scarcely possible to estimate the true relations of Cryptogams to Phenogams. 33. I shall proceed now to explain the points of difference and resemblance which exist between Club-mosses and Conifers, for if any Cryptogams are allied, it must be these.+ Selaginella, for example, produces two kinds of spores, a smaller and a larger, in closed processes. Externally, and in their mode of gen- eration, both these resemble the spores of allied Cryptogams, but * This seems to beasort of alternation of generations. The first cycle is completed by the well-known reproductive bodies ; the second by the spores produced on their germinating threads. + For figures illustrative of the text look forward to the section on Club-mosses. For full information, Hofmeister’s two Treatises must be consulted. 46 INTRODUCTION TO CRYPTOGAMIC BOTANY. the smaller ones are not of the same imports the larger. a. The smaller spores which consist of a single cell, within a proper envelope, remain some months after being sowed without much change. Gradually, however, their protoplasm generates a number of cells, each of which contains a spiral spermatozoid. The smaller spores, then, which do not germinate, are ana- logues of antheridia, though they resemble in their mode of development ordinary pollen grains, which are clearly homologues of spores. They are, in fact, of far greater dignity than the pollen grains of Conifers, though, in point of fact, homologous with them. The grumous fovilla of these latter, in every respect except in function, differs from the ultimate contents of the small spores. 6. The larger spores consist also originally of a single cell,( but in the process of growth they acquire an envelope, and have a disc applied to their inner surface consisting of a double row of cells. This exists while they are yet in the mother-cell from which they are derived. The formation of this disc is the only thing in the shape of germination which they exhibit.) AJ After some months, @ similar disc is formed within this, and the upper disc contains)a » number _ of little flask-like bodies, communicating above » with the open air, in “which, by impregnation, an. _embryo_is developed_ “from a single cell filing the base of the body, which is “called an Archegonium. I am not aware that the formation — of the embryo-sac within the nucleus of Pheno enogams has been observed accurately.* It is quite certain, however, that it is not a mere cavity formed in the cellular tissue of the nucleus, for if so, it would never become free and “project ‘beyond its aperture, as it does in Crucifers, rouch less would there be a plurality of such sacs as in the same plants, sometimes branching and assuming a variety of forms.t We have here, then, a plurality of embryo-sacs, a tendency to become free, and at the same time to germinate. We do not know how these multiplied embryo-sacs arise, whether from the division of one cell, or the swelling out of distinct con- * Schleiden says that it is the dilatation of a central cell, and such it probably is. A direct proof of this is evidently one of extreme difficulty. { Tulasne in Ann. d. Se. Nat, sér. 3, vol. xii. p. 21. INTRODUCTION TO CRYPTOGAMIC BOTANY. 47 tiguous cells. There is not, however, I think, sufficient to justify us in considering the large spore of the Club-moss as homo- logous with the embryo cell of Phznogams, allowing as much weight as possible to the facts. These large and small spores are identical in origin, notwithstanding their difference of size. Both, therefore, are homologues of pollen grains, but we have no no example ‘of a pollen grain producing an embryo in its pro- toplasm, though the cells of anthers, like other cells, may be capable of development into buds. The embryo-sac, then, in the Conifer, after many months is slowly filled with endosperm ; cavities are formed at the apex, in addition to the large central cavity; particular cells in these little cavities or corpuscles divide, giving rise to a bundle of threads, and after impregnation, the tips of these threads produce the embryos, with the radicle pointing to the aperture of the nucleus. Now, if the progress of the spore of the Club-moss be followed, even allowing that it is the homologue of the embryo- cell, the dise ought to be the homologue of the endosperm; but then if it were so, the whole leafy plant of a Moss or Liverwort, which is clearly homologous with the disc of the Club-moss spore, must be equally the homologue of the endosperm, which is so clearly absurd, that at once all notion of homology ceases. Allowing then the disc to be analogous to endosperm, the archegonia are analogous to the cavities or corpuscles at the upper part of the endosperm of Conifers.* The central cell of the group, of which in the early stage the archegonia consist, is analogous with the cavities of the corpuscles. A cell is similarly formed from its protoplasm, but then the develop- ment of this is quite different. Up toa certain point there has been considerable resemblance, but now, with strong analogy, there is essential difference. 34, In the Club-moss, a single cell at the base of the arche- gonium divides ; a process is formed upwards, analogous only * It is sometimes said that these bodies in Conifers are without ex- ample in other orders, but they are, possibly, only modifications of the suspensors, as in Serophularia, from the swollen end of which the em- bryo finally grows. 48 INTRODUCTION TO CRYPTOGAMIC BOTANY. with the suspenders of the embryos in Conifers ; for this pro- cess remains much in the same condition afterwards, while the lower half of the basal cell, which was really and immediately the embryonic cell, at length forms by division a cellular mass, or, in point of fact, a true embryo,with the radicular end pointing one way, and the foliiferous end another. The order of the form- ation of the cells from which the embryo is generated, is exactly contrary to that which takes place in Conifers; the radicle is not continuous with the suspender, and does not point to the apex of the sac. There is, however, a semblance of two coty- ledons, and besides the fact of numerous cavities existing in the same disc, analogous with albumen, occasionally two em- bryos are formed in the same cavity. It must not, moreover, be concealed that a bundle of spiral vessels passes from the trunk into each leaf, and that there is a disposition to form adventitious buds in consequence in the axils of the leaves ap- proximating the plant to Pheenogams, insomuch that any frag- ment of the stem will grow. In Marsilea the spores resemble still more closely the embryo-sac, for they are ultimately filled with cells. In other cases, the cellular mass resulting from germination loses every resemblance to endosperm, and, in fact, forms the plant, on which fructification is developed by means of archegonia, essentially the same as those of the Club-moss, in the first instance, but very different as to the results. In the Club- moss an embryo is formed which reproduces the species; in the Moss, a theca is formed which contains spores for the reproduc- tion of the species. The fertile cells in the archegonia, in the two cases, were perfectly homologous, but the productions of those cells, though still homologous, have only remote affinity;+he closer affinity was shown at an earlier stage of growth. 35. What, then, is the relation between such Phenogams as Conifers, and such Cryptogams as Club-mosses? There is not the slightest transition from the one to the other, though certain resemblances, indeed close analogies, exist, and there is some outward conformity in the results. The ends, how- ever similar, have here been produced by very different means, and the several steps by which the similarity has been produced, arising gradually from the simplest organism, are INTRODUCTION TO CRYPTOGAMIC BOTANY. 49 such that all question of affinity seems to me to be at an end, however enticing the points of resemblance are. Conifers are highly-organised Phenogams, and Club-mosses are the most so of Cryptogams ; but if we take into consideration the immense difference of general structure, and much more of manner of development, without our being able to point out any intermediate plants whose relations on either hand are doubtful, I do not see how we can venture to say that there is any affinity. 36. Transitions from one group to another may take place in various ways; as, by the union of the characters of two osculant groups in a single species, so as to make it doubtful to which the species belongs, as, for example, in the transition from Uredinee to Tremella ; by the sudden alteration of the mode of development of some particular organ, as in the spores of Equiseta and Ferns; or by the mutual interchange of many characters, asin Phenogams. In the monopetalous hypogy- nous orders, as, for instance, in Scrophularinew, Solanacee, Acanthacew, Bignoniacee, and Convolvulacece, which are so intimately related that they can neither be technically divided nor arranged in a linear series, we have an excellent example, and so with A pocynee, Gentianee, Loganiacee, which are simi- larly connected, not only with one another but with some of the above, and even no less intimately with the Epigynous orders, Rubiacee and Caprifoliacew, as has been shown in an admirable paper of Mr. Bentham’s, lately read before the Linnean Society. Between Conifers and Club-mosses there is no such connection. By a curious diversity, the spores which immediately reproduce the species in the greater part of Fungi, give rise to a sort of prothallus in the msts and wheat mildews. Here, then, is a slight foreshadowing of the new series of developments in higher Cryptogams, in which the spores produce a prothallus, and, in so doing, at length, by a wonderful chain of analogies, simulate the formation of embryos in Phenogams. The Club-mosses, and especially the Lepidodendra, are probably the highest limit capable of being reached by Cryptogams, and their mode of fructification the nearest to that of Phenogams. But there is no connecting 4 50 INTRODUCTION TO CRYPTOGAMIC BOTANY. link, and therefore no affinity. We have merely two parallel series, of which the results are, to some extent, the same. A great advance has certainly been made in the Cryptogam; a true embryo has been formed ; there is, to use a German phrase, a greater differentiation of parts; but, after all, there is a wide and impassable gulf, between the two, and in the absence of all evidence of a bridge passing over the gulf, it seems to me unphilosophical to allow any close affinity. 37. It has sometimes been urged that there is a prothallus in Conifers which brings them near to Club-mosses. If there is any prothallus it is the endosperm, and that certainly has the same functions and the same signification in Conifers as in other plants, though it may be more completely developed before the formation of the embryo than elsewhere. The suspensors in other Phenogams are possibly the same organs with the corpuscles of Conifers, or, at least, analogous with: them.* 38. But it may be well to look to one or two more points in Conifers as regards comparative dignity. The slow develop- ment of the fructifying organs, and the curious phenomena in the pollen grains preceding the protrusion of the pollen tubes, seem to be proofs of superior dignity. The highest recent Cryptogams are doubtless the Club-mosses, in which the process is extremely slow; the moulds, on the contrary, fruit and reproduce their species within a few days. In respect to the naked ovules, there is little difference between im- pregnation by means of a stigmatic tissue and immediate impregnation through the micropyle. There is precisely the same process in both when once the pollen reaches the micropyle. The only difference is in the preliminary act. It is not, perhaps, quite so clear that impregnation may not take place sometimes without the intervention of a stigma, even in plants which possess that organ. Pollen grains must sometimes fall upon the micropyle of the naked’ ovules of Reseda, and as they may be made to germinate+ * Tf these suspensors are deduplications of the embryo-sac, the cor- respondence of the corpuscles and archegonia is far less striking. t Reissek Act. Nov. vol. xxi. P. 2, p. 469. INTRODUCTION TO CRYPTOGAMIC BOTANY. 51 artificially, it is conceivable that the pollen tube may, in certain cases, penetrate, or, at least, come in contact with the embryo-sac, quite as easily as by means of a, stigmatic tissue. Dr. Hooker has lately made some experiments of cutting off the stigmatic rays of unimpregnated poppies, and yet has obtained perfect seeds.* It is alleged that direct impreg- nation is a sign of inferiority, resembling as it does what takes place in many reptiles. But the whole matter of impregnation is so very different in animals from the correspondent process in the higher plants, that no weight can be attached to such a resemblance. Cryptogams might be considered of superior dig- nity to Pheenogams, for example, because of their spermatozoids. The result of impregnation in the case of lizards is, in many respects, far inferior to animals produced from more normal impregnation. But as much cannot be said of Conifers, nor do I think them at all degraded, because impregnation does not take place without the intervention of a stigmatic tissue. In many reptiles, impregnation is as precarious as in trees with distinct sexes, the water in the one case being the vehicle, in the other the air. Besides, in Gnetum and Ephedra there is an organ developed which performs the functions of a stigma, though not arising from the placenta ;+ but even supposing it to be wholly inoperative, it is at least representative, like the mammz on the breasts of male quadrupeds, which do oc- casionally contain milk as in the female. It is not, indeed, quite clear whether the simpler mode, judging by analogy, may not be of the higher dignity. No one would pretend that in those cases where the impregnating substance is stored * Hooker in Gardener’s Chronicle, 1855. + Much, of course, depends upon the fact, whether impregnation is effected before the formation of the envelope, which bears the pseudo- stigma. The argument would be stronger if the older views of the structure of the flower were correct, which, on examination, appears to be the case; the envelope in question is external to the nucleus, and therefore the processes cannot be the same with the curious bodies which occur in Zhuya, In Larix the stigmatic cells, as figured by Geleznoff, Ann. d. Sc. Nat., Sér. 3. vol. xiv. tab. 13, fig. 15, 16, whose paper may be consulted respecting the peculiarities of the pollen in Conifers, are equally independent of the placenta. 4 ® 52 INTRODUCTION TO CRYPTOGAMIC BOTANY. up in certain vesicles,* after deposition by the male, as in Aphides and Gryllus, there is any indication of higher dignity, though the process is more complicated ; but even granting that the naked ovule may be the less perfect organ, the whole system of vegetation is so entirely different from that of the highest Cryptogam, that I am unable to see a particle of affinity, nor, indeed, in the vegetable world, as at present known, am I able to trace any close connection between Phenogams and Cryptogams, look which way we may. Both, indeed, are vegetables, and both have certain points of resemblance, and similarity of organs; but in every- thing which regards essential character they are altogether distinct, as, on the other hand, I am inclined to think is the case with the two great divisions of Endogens and Exogens: there may be some difficulties as to the order of development, but still, in every case, the grand distinctive pomts remain fixed and certain, and the separation of such plants as Tamus and its allies, under a distinct order, serves only to confound distinctions which appear to me absolute. 39. One fertile origin, indeed, of such notions as to the close relation of organisms in reality so widely divided, depends on the prevalent idea that there are no such things as definite groups in nature. All, it is said, pass into each other by insensible gradations. Itis necessary, however, to have definite notions of the typical characters of families. It is true certain characters may be common to two groups, but this does not prove affinity. There is a definite distinction between en- dogenous and exogenous growth, between a Monocotyledon and a Dicotyledon, between a Pheenogam and a Cryptogam; and though there may be modifications of these distinctions, yet these modifications often take place at points as far as possible distant from each other; not where endogenous and exogenous plants might be supposed to be confluent. Dictyogens, for instance, are supposed to approach Exogens in their leaves and in the arrangement of their tissues, but their embryo and the development of their wood are as distinctly mono- * Lespés Mémoire sur les Spermatophores des Grillous, Ann. d. Sc. Nat., Sér. 4, v. iii., p. 366. INTRODUCTION TO CRYPTOGAMIC BOTANY. 53 cotyledonous as in plants which represent the typical struc- ture of the stem more completely, and multitudes of similar instances might be alleged.* If Nymphca, again, be taken, the embryo, when properly understood, is as distinctly dicotyle- donous as in any other plant ; and if further proof were wanted, the germination of the common peony should be compared with it. Each group of organisms has a circle of its own in which they are combined by close affinities, and these circles are not the less definite, because there may be an osculating point with some other circle. The two great groups of fungi, for instance, characterised by naked and inclosed spores, are perfectly definite. Even in those cases where the inclosed spores are reduced to one closely invested by the outer coat, so as to look naked, the morphology is as definite as ever, and the genus Haplosporiwm in which this character is most pro- minent is, in fact, one of the noblest, and by no means a form of transition. Except where the naked spore isa secondary form of fruit, there is never the slightest doubt as to the true affinity. It may be true that in Hymenogaster a sac is occasionally developed round the spores, but the spores are then as perfect and as definitely placed as in other species where there is no such sac, the presence of which is a mere analogy and not an homology. What, in point of fact, is necessary to the suc- cessful study of this or any other branch of science, is to avoid mere speculation ; to endeavour to grasp, if possible, the exact meaning and import of every modification which occurs, by close comparison and observation of nature. A person who should set out on an investigation of the phenomena of impregnation in Phanogams, with a decided prejudice in favour either of the Schleidenian notion of the penetration of the end of the pollen tube into the embryo-sac, or of its simple contact with the sac apart from any introversion, would be sure to see facts with eyes already more than half-blinded. If any proof of this were wanting, it would be found in the circumstance that the same identical specimens and preparations have very lately led two different German botanists to precisely different conclusions. The real object * The truth is, the majority are undoubted members of Liliacee. 54 INTRODUCTION TO CRYPTOGAMIC BOTANY. should be to ascertain exactly what the structure is, and then to build upon the observation ; but to place no superstructure whatever on facts which admit of two distinct interpretations, one of which is as plausible as the other. A great degree of caution is wanted, and of good faith too, without which error is inevitable where such delicate and precarious manipulation is required. The Cryptogamic student, if he enters on more than the mere determination of species, will find enough to call for the exercise of no ordinary acuteness. Let him, for instance, strive to ascertain exactly the nature of the communication between the plant and matrix in the parasitic fungi, which belong to the group of rusts and mildews, and he will soon find, if he is wise, that he cannot well be too cautious before he draws his conclusions.* 40, A few words must still be said about Cycads, both on account of the remarkable fact of the circination of the pinnate leaves in many species, and of the deviation from the normal venation of Zamic in Stangeria (Fig. 1), resembling perfectly that of ferns. That there is a resemblance in the vegetative organs here is undeniable, as there is in those of Podostemads to Hepatice, or of Balanophore to Fungi; and were this accompanied by changes in the fruit at all approximating it to that of Cryptogams, it would have considerable weight. We have, however, as distinct a dicotyledonous embryo in Cycads, as in any Exogen, and perfect pollen. The sper- matozoids of Acrogens are so totally different from this latter, and the whole history of their vegetation, that, in spite of one or two points of resemblance, and those not universal, I cannot see here, again, anything approaching to affinity, though there is a foreshadowing of structures to * In books intended for students, an author cannot be too sure of the facts which he lays before them ; nor he too severe in his application of them. Otherwise his reader will throw down the book in despair, since he can obtain no definite notions from it, or will gradually fall into the same loose way of reasoning himself, and derive no lasting benefit from it. Hemay cram up its contents for examination, and when they have answered that purpose, they will be put out of mind for ever, He will, in fact, have acquired nothing solid ; nothing that can help him to the acquisition of fresh knowledye. INTRODUCTION TO CRYPTOGAMIC BOTANY. 55 be met with in a different and inferior series, but not in points indicating inferiority. 41. External resemblance is very often deceptive in tracing the relations of plants to each other, and an utter difference of aspect may be consistent with close affinity. Similar organ- ization will sometimes exist in widely-separated plants, while difference of structure will be found even in plants of the same genus where habit is different. The distinctive mark, for instance, in coniferous wood, which was, at one time, thought decisive as to affinity, is not confined to Conifers. In Magnolias and Witch Hazles (Hamamelidacew) we have the same structure, whatever pains may be taken to explain it away; and if it is considered that ordinary woody tissue succeeds uniformly to the glandular tissue in Conifers, as the year advances, the one being actually produced from the other, we need not feel surprised that it is not certainly indicative of affinity. Nothing can be much closer than the general appearance of the fruit in Pepperworts and Arads, and if annual stems be examined there are the same scattered fascicles of woody tissue. The inflorescence, indeed, of all is not the same, but this would merely be exceptional were the structure of the stem really identical; but take an old pepper stem and you have strong plates of medullary tissue, and may count the annual rings. Hence, though, up to a certain point, there is endogenous structure (with the exception of the cha- racteristic crossing of the woody bundles), you have the two cotyledons to convince you that such eminent botanists as Blume and Richard have been led astray by analogy, when they considered them as true Endogens. There is, indeed, some question, raised by Blume and Bennett, as to the order of the development of the spiral vessels, but be the point de- termined as it may, the medullary rays, reticulated articulated leaves, dicotyledonous embryo, and, above all, the germination properly understood, must be decisive as to real affinity. In like manner the Menispermads were supposed to present an endogenous structure, but if branches of sufficient age are ex- amined, there is no question about the case; and even were this not the fact, the whole structure of the embryo would 56 INTRODUCTION TO CRYPTOGAMIC BOTANY. never sanction any notion of a relation to Endogens. The exigencies of climbing plants, which suffer great compression, require a peculiar arrangement and structure in their com- ponent parts. But other instances may be produced equally full of instruction. 42, Take, as a third instance, the pseudo-exogenous growth of the larger Seaweeds and Usneoid Lichens. A transverse section in many of the former presents zones, formed, period by period, corresponding with the development of the lamine, roots, or branches, as is very visible in the stems of Lessonia. Fig. 15. a. Sections of Usnea melarantha. b. Section of stem of Lessonia, showing the pseudo-exogenous growth. Both from specimens communicated by Dr. Hooker, There is no line of separation between the cortical cells and the zoned portion, as though there were at once a centrifugal and centripetal growth, nor are there any wedges of medul- lary tissue from the central pith, which is so conspicuous The difference, then, between this and real exogenous growth is very great, and whether the innermost cells of the cortical layer are gradually changed, the terminal cell dividing, or whether INTRODUCTION TO CRYPTOGAMIC BOTANY. 57 increase takes place by the division of the last-formed cells of what may be called the wood, as is the case in Dicotyledons, we have still something very distinct, though bearing a very decided analogy. The latter mode of growth is the more probable, when the similar formation in Usnea melawantha is taken into account. In this case the structure of the outer portion of the medullary substance, which is often at length quite free from the cortical layer, is so loose, though still capa- ble of growth, and of producing, at times, gonidia, that it can increase, independently of the other, and so imitate, very closely, exogenous growth. 43. In Usnea melaxantha there is, however, as stated by Dr. Hooker, in the Antarctic Flora, something very dis- tinct from what takes place in other Lichens, as far as is at present known. “Proceeding from the circumference there is, first, a horny coloured cortical layer, answering to what is called the cortical layer in Lessonia, and to which, in that plant also, the coloured chromule is chiefly confined : secondly, the layers of intermediate lax tissue, successively deposited, though much more obscurely than in Lessonia: and thirdly, the central thread, which is a stout axis answering to the elliptic core of Lessonia, but in this Lichen becoming so lax towards the centre as to inclose a cavity in the older stems.” Here, again, we have a close imitation of exogenous growth ; added to which, in some Lichens, there is often a solution of continuity between the cortical and medullary layers; but no person would pretend that this is any sign of affinity, though it is curious that the lamine in the Lessonia are analogous in their effect to leaves,* and that this mode of growth should be exhibited as at present known only in the noblest of all Lichens. It is quite evident, however, even in species where no zones exist, that increase in size takes place in the same fashion. It is very curious, that in specimens of Usnea melaxantha, just received from the Falkland Islands, sections of which are given above (Fig. 15), though there is no such exogenous appearance, * According to Schulz, in Flora 1853, the zones in the stems of Lami- naria are developed upwards, and coincident with the development of additional roots, 58 INTRODUCTION TO CRYPTOGAMIC BOTANY. the central cord, which consists of a hard cartilaginous mass of closely anastomosing threads as in the external coat, is divided into wedges so as to form a further analogue of an Exogenous stem. In process of growth those plates divide, and resemble some of the more anomalous arrangements of the wood in Exogens. 44, The differences of habit, and even of structure, in closely allied flowering plants, are equally deceptive. Take, for in- stance, the climbing and the erect Bawhimias. The flattening or angularity of the stem, in this and in many other genera of the same natural order, as also amongst Sapindacew, Bigno- niacece, Malpighiacee, &c., the compression and torsion to which they are subject, and, in fact, the necessities of the plants, induce anomalies in the direction of the medullary rays, the development of parenchyme, the intrusion of cortical matter, &e., which almost defy investigation.* In some species as Cassia quinguangulata, Rich., which is not always a climber, there is at different epochs, and under different circum- stances, a very different structure,t insomuch that Criiger says expressly, that if, on the one side, perplexity arises from the complication of the wood, on the other hand the differences in individual plants show that a great part of these anomalies may depend on accidental causes, as soil, position, &e. If the office of the ducts be really to carry air to every part of the plant, it is clear that the size of these ducts must be increased in proportion as the stems are subjected to distortion and compression. 45. Take, again, the difference of structure in different species of A/yzodendron. In M. brachystachywm, the wood is deposited in two series of wedges, not always very regular, and at first sight calling to mind, as regards their disposition, some of the climbers mentioned above. In M. quadriflorwm, the inner series is represented by a single oblique wedge in the axis, while in M. linearifoliwm, there is but a single series. When the disposition of the various tissues of which these are * See Criiger in Bot. Zeitung, 1850, 1851 ; Mettenius in Linnea, vol. xix.; the Memoirs of Jussieu, Schleiden, &c. + Criiger, Bot. Zeit. 1851, p 469. INTRODUCTION TO CRYPTOGAMIC BOTANY. 59 composed, and also the medullary rays are considered, the modi- fications are greater than would frequently be found in distant genera of the same natural order; but in M. punctulatum such a difference exists, that Dr. Hooker, speaking of this in comparison with the other species, says, “that no one, from an examination of the wood alone, would hesitate in pronouncing them to be plants widely separated in a natural system.’* 46. It is strange enough to see the medullary rays in M. bra- chystachyum and quadriflorum, consisting of uniform tissue, while in M. linearifolvwm, they abound in conspicuous masses of woody cells, which exist also in the bark; but while the pith of other species is simply cellular, in M. punctulatum it consists of a dense mass of woody fibres (pleurenchyme), and as a consequence, there are no true medullary rays. Look again at the strange difference which exists between the dry fruit of Myzodendron, and the viscid fruit of Loranthus and Viscum, and the still more marvellous arrangement by which the dry tissue of the former, in the condition of tendril-like threads, clasps the stems of the plant on which it grows, in order to keep the germinating seed in a fit position for the radicle to exert all its force at one point, so as to enable it to pierce the bark, thus answering the same purpose which is secured by the slime of Loranthus or Viscum. Or again, amongst the same plants, look at the utter diversity displayed by the anthers ; the bilocular anthers of Loranthus, the unilocular of Myzo- dendron with their central columella, and the cribriform pollen cavities of Viscwm. 47. The structure of the ovules in Cryplocorynet (Ambro- sinia ciliata, Roxb.), so different from that of allied plants, will give us another excellent example. The embryo pro- jecting at an early period beyond the walls of the nucleus, the enormous many-leaved plumule thrusting the radicle on one side, the rapid fall of the cotyledon, even before the seeds have left the capsule; but above all, the direction * Hook. Fl, Ant., p. 297. The whole of the above information is derived from the Antarctic Flora. I have also a beautiful specimen of the wood of M. brachystachyum by the kindness of Dr. Hooker. t Linn. Tr. vol. xx. p. 263. 60 INTRODUCTION TO CRYPTOGAMIC BOTANY. of the radicle away from, and not towards the apex of the nucleus, are all anomalies which have no parallel in its closely-allied genera. “Nothing,” says Mr. Griffith, “can prove more satisfactorily than the present instance, the abso- lute necessity of tracing anomalous forms back to the earliest period of their development. In this case, the process is at- tended with the desired effect, viz. of reducing anomalies to the ordinary type of formation. It is very evident that the form of the embryo, immediately before its conical apex projects through that of the nucleus, closely resembles the usual form of these organs in other Aroides, since we have a superior radicle,* a cotyledon, and a tendency to the formation of a lateral slit, as indicated by the depressed areola.” 48. The best characters are often derived from the germi- nation and structure of seeds, but in nearly related plants, these matters are often very different. In Poonia and Nymphea, we have a germination greatly resembling that of Endogens ; in Delphiniwm fissum, and some other species, there are two cotyledons joined by their petioles, so that the plumule is obliged to force its way out at the base; a similar structure occurs in Buniwm luteum, Prangos ferulacea,t and Dodecatheon Meadia. In some Um- bellifers the anomaly is, however, much greater, the two cotyledons are soldered into one, and no plumule is produced, but the energies of the plant are devoted to the formation of a tuber, which sends up a bud in the succeeding year ; this is the case in Buniwm Bulbocastanwm, and in various other genera ; I believe it is the case, also, in Thapsia villosa ; in Corydalis cava, and many other species, however, a single cotyledon only is produced, and, as in the last case, it pro- duces a bud the following season from the tuber. In * The radicle is, in fact, pushed aside by the enormous plumule. If analogies are wanted, compare the plumule just when the cotyledon has fallen with Riccia natans. Tt In Prangos ferulacea, the first leaf of the plumule makes its appear- ance at the point of confluence of the two cotyledons, the others being free. I have availed myself here of an excellent paper, by Bernhardi, in Linnea, vol. vil. p. 561, See, also, Irmisch, in Botanische Zeitung, 1856. INTRODUCTION TO CRYPTOGAMIC BOTANY. 61 Leontice there are two cotyledons with, however, a similar formation of atuber. In Linaria arenaria, a shoot is formed below the cotyledons, a circumstance which has been observed also in Huphorbia Lathyris, and some other species. In Cyclamen the germination is that of Dodecatheon, but only the petioles of the cotyledons are developed. 49. It would be easy to multiply such examples to almost any extent, were it necessary to do so. I shall, however, still point out one source of fallacy in the estimation of affinities, which arises from the extreme difficulty of appreciating them till the real clue is found out. Fries, indeed, has shown a wonderful tact in ascertaining the affinities and nature of cer- tain Fungi, but till the true structure of the hymenium was known in the Puffballs, Stinkhorns, Birdsnest Pezizas, and a multitude of other instances, it was almost impossible to ar- range them in any natural sequence. The true affinities of such genera as Vidularia and Sphwrobolus, could never have been imagined without some such clue. The same may be said again of the naked-seeded truffles; nothing is more clear than their real nature, now that the structure of the hymenium in the higher Fungi is known; and as regards the truffles with inclosed spores, the discovery of Genea, and much more of Hydnocystis, which is a mouthless Peziza, at once makes the passage from Tuber to Peziza evident, the one having the rough sporidia of P. radula, the other, the smooth sporidia of P. arenaria, which is almost hypogeous. Who could guess, at the first glance, or, indeed, without a knowledge of the fruit, that there was any affinity between Callitriche, Hippuris, and Onagrarie, or, much more Myrtles? Take again the affinity of Lemna and Arum. There is not the slightest external sign which could lead to a notion of affinity. and the whole structure of the plant is against such a notion. The genus Pistia, however, on the most superficial glance, indicates an affinity with Lemna. The habit is the same, and there is the same highly-developed pileorhize, which is no special organ, but the same thing with the pileorhize in more complicated plants. The inflorescence is, however, no longer so thoroughly simple. There is a distinct spatha, and a cup- 62 INTRODUCTION TO CRYPTOGAMIC BOTANY. shaped calyx to the monadelphous stamens, though the male and female flowers are associated; and an ovary with many erect ovules. Ambrosinia makes yet another step. The spatha is well developed, and whether or no we consider the ten twin anthers,* as belonging to as many stamens, we have a spadix in the dissepiment, with the single female flower on the one side, and the male on the other. The position of the ovules, however, which is totally different from that of Pistia, is a curi- ous instance of anomaly. It is but a step from Ambrosinia to ordinary Arads, and thus the affinity of Lemna to Arum is proved, an affinity which could scarcely have been made out without the intervention of Pistia; and when one such affinity of a degraded form is ascertained, there is a clue to other simi- lar affinities. One of the most striking instances of difference of habit, is that between Cactus and Ribes, an instance which was familiar in the mouths of all, when the natural system first began to replace the Linnzan in this country, and yet no affinity is more sure; and almost equally striking is that between nettles and figs, to which Dorstenia gives the true key. On the whole, then, it is plain that immense differences on the one hand, should not at once determine against affinity, nor on the other hand, should striking resemblances mislead us. We must not judge by isolated facts, but, as far as we can, by the whole history and morphosis of plants, otherwise we shall never arrive at affinities; and if this course be pursued, I know of nothing which can confound a single Cryptogam with the lowest Phznogam, and much less with Phenogams high in the scale, like Conifers. 50. It may be a very good answer to the question, what Cryptogams approach nearest to Pheenogams, that Club-mosses present the greatest similarity in habit and in fruit. But we cannot ignore the fact, that Club-mosses bear spores like other Cryptogams,which, apart from the plant, undergo a variety of changes, in consequence of impregnation, at a distant period, and at length produce a plant, which springs at once into a new * See Cesati Ueber die Gattung Ambrosinia, Linn. v. ix. p. 281, tab. v. fig. 8, 9. INTRODUCTION TO CRYPTOGAMIC BOTANY. 63 individual, without any intermediate rest; that impregnation takes place by spermatozoids, and not by a pollen tube; that the embryo grows in an entirely different way ; that the radicle does not point to the foramen, and that, after all, the mode of growth in the stem is totally different. When, moreover, we weigh the arguments, as to the comparative dignity of Conifers, and see that they are certainly not inferior to a host of other Phzno- gams, some of the highest of which have fruit of the very simplest kind, though we may recognise very curious resem- blances, and though we may admit that these are decided analogies, we shall not be prepared to ascribe any close affinity between them. 51. The various theories which have been mooted from time to time respecting spontaneous or equivocal generation, have been, for the most part, grounded on the development of Cryptogams, and of those animals which are lowest in the scale of creation. Such fancies, however, have by no means been confined to them, for no less remarkable phenomena occur occasionally among Phanogams, a few of which may be mentioned. It is, for instance, a well-known fact that on our eastern coast, when land is taken in from the sea by means of embankments, and the tide finally excluded, the first vege- tation which appears is a crop of white clover. When heath is burned in many districts the same plant makes its appear- ance. Sisymbriwm Irio covered every ruin after the Great Fire of London in 1666, and in many parts of the United States the certain fullower of extensive conflagrations in the forests is Lactuca elongata, which, in consequence, is known by the name of fire-weed. Now it would be quite as rational to suppose spontaneous generation in these cases as in those of Fungi, the lower Algze, or Mosses. The woods in my own neighbourhood are sometimes blue with Columbines the year after the underwood is cut, though it may be difficult to find a plant at other times; and it is notorious that certain Orchids, as Ophrys apifera, Epipactis latifolia, &c., appear only periodically in situations which are sometimes quite naked, sometimes covered with Brushwood.* But in these * Some.of the Orchids produce bulbs which are many years before 64 INTRODUCTION TO CRYPTOGAMIC BOTANY. instances the overwhelming shade is quite sufficient explanation of the dormant seeds and tubers, and the other cases would admit probably of as easy a solution, were they studied on the spot. Now as regards Fungi and the lower Alge, it cannot be denied that their appearance is often puzzling enough, but as much of the mystery which was formerly attached to the phenomena exhibited by intestinal worms has vanished under the investigations of Steinstrupp, Siebold, Van Beneden,t &e., I doubt not that those facts which still appear so perplexing, will admit some day of easy explanation. Wherever proper pains have been taken to exclude every possible source of error, no moulds or animalcules have ever made their appearance, without the possibility of the access of previous spores. After prolonged boiling and exclusion of the external air, as capable of conveying spores, or its admission only after first traversing some fluid, as sulphuric acid, which is destructive of life both in the animal and vegetable world, and therefore would char any spore that the air might contain, not a living molecule has ever originated in any organic substance or fluid charged with organic matter. And the same may be said of reputed metamorphoses of Algee into Fungi, and the contrary ; both notions rest either on imperfect observations, incomplete they come to maturity. A recent memoir of Fabre, in Annales des Sc. Nat., relative to the development of the tubers in Orchis hircina, may suggest some hints on this subject. Ann. d. Sc. Nat. Sér. 4, vol. 4, } I allude more especially to the origin of flukes, tapeworms, &c., from minute creatures nursed in the bodies of other animals. The con- nection between the Cystocercus of the pig and Tenia Solium the common human tapeworm ; that of cysts in the heads of sheep and the tapeworm of the dog ; a parasite of Lymnea and the sheep fluke, are now established beyond doubt, and these are not the only examples. It would be curious to ascertain of what worm the sorices of the human liver are the infant condition. That the animals hatched from the ova of the tapeworm should be able, notwithstanding the powerful jaws with which they are furnished, to travel, in spite of all impediments, as far as the brain, even though it be by penetrating the blood vessels, is perfectly astonishing. It is easier to estimate the progress of such species as are nursed in the liver, by way of the hepatic duct. INTRODUCTION TO CRYPTOGAMIC BOTANY. 65 knowledge of the objects themselves, or confusion respecting the proper limits which separate the animal and the vegetable world. They were, a few years since, almost universal in Germany, and were received with favour by a few French Botanists, but have never gained much ground amongst our- selves, except in popular belief. In France and England at the present time they are all but exploded, and I am happy to see that German botanists are beginning to follow in the same direction. Some, however, still lean to the old notion, as, for example, Dr. Cohn, in a late article on the mould which is so fatal to flies in autumn, and which he supposes to arise by a free development of vegetable cells in the diseased blood.* With respect to parasitic Fungi, which have been regarded either as mere metamorphoses of the parent cells, or as spontaneously generated, it must be borne in mind that one species at least, Tilletia Caries (the common Wheat Bunt), may be propagated by the spores at will, The infected plants are at once dis- tinguishable from those which have had no contact with the parasite; and, though not the slightest trace of fungal threads can be found in them, it is quite certain that something capable of reproducing the species is present, either in the inter- cellular passages or protoplasm. This is applicable to hosts of fungi of very different affinities which protrude through the tissues of decaying branches. In the case of Botrytis infestans, the fungus which is, in my opinion, the proximate cause of the potato murrain, the walls of the cavities of the carpels of Tomatoes are often covered with the fungus, though there is no communication with the outward air; and a crop of the mould has been seen to grow in a few hours from the cut surface of a diseased potato, even though the foliage itself had exhibited no traces of the parasite. 52. Were spontaneous generation true, and plants produced * Hedwigia, 1855, p. 59. His words are, “The influence of the spores of Empusa in the appearance of this fungus, and of the disease in flies, is by no means evident, since the genesis, the chemical and optical cha- racters of the numberless free cells in the blood, the absence of a special expanded mycelium, and above all the whole history of the develop- ment, seem to concur in favour of the origination of the cells of the Empusa from the diseased blood.” 3 66 INTRODUCTION TO CRYPTOGAMIC BOTANY. like chemical substances from inorganic matter, according to definite laws, the species would, in all probability, admit of far more accurate definition : at any rate the species of Cryptogams in general are not more certain than those of Phanogams. Some, however, maintain, on the contrary, that there can be no certain species of Cryptogams on this account. There are, however, in no part of Botany more certain species than those of the higher Hymenomycetes when properly understood, especially, as Fries remarks, in the genus Cortinarius. 53. Cryptogams, then, as a distinct class of organised beings, and from various considerations connected with them, form a very important object of investigation. They are, for the most part, the first objects which clothe naked rocks when they emerge from the bosom of the sea, and they afford the last indication of vegetable forms under degrees of heat and cold which are fatal to other members of the same kingdom. Stones of the closest texture, if there is a proper degree of moisture, even under the direct’rays of the sun, soon exhibit traces of Cryptogams, and in hot springs, at temperatures which seem almost fabu- lous, certain species will flourish; while the depths of the Arctic and Antarctic Seas and the brashy pancake ice are equally productive. There is, moreover, a singular variety in the nature of these bodies, so that there is scarce a part of the surface of the globe where they may not be found. Both fresh and salt water, within certain limits as to depth, and tempe- rature, teem with them; arid plains, turfy peat-mosses, the recesses of woods, the deepest mines, the surface even of icebergs, and, if it be not a mere fancy of Ehrenberg’s, the bowels of the earth and the regions of air are not exempt; and then not only are there multitudes of forms amongst them of excessive minuteness, but some of the noblest objects in nature, as the tree ferns, belong to the same class. They are often the pests of man, spoiling his provisions, and inter- fering with the operations of art. Neither are living organisms exempt. True parasitism exists in Cryptogams, which, in con- sequence, give rise to a host of diseases, especially in the farm and garden, and wherever vitality is very low, certain species are capable of establishing themselves on exposed surfaces INTRODUCTION TO CRYPTOGAMIC BOTANY. 67 even in the animal kingdom; nay, they grow occasionally within cavities perfectly cut off, as it should seem, from the out- ward air, or where the structure of the tissues is so close as scarcely to admit of the penetration of any save fluid matter. The species meanwhile have a far greater geographical extent than plants in general; similar climates constantly afford similar species, though with different species intermixed, of which many are altogether local. In every country they constitute an im- portant element in the number of species ; and in some, as in Sweden, they are four or five times as many in number as the Phzenogams, while in South Shetland, there is but a single Phenogam, and in Cockburn Island, the nineteen species which form its Flora are all Cryptogams. In the tropics, gen- erally, this proportion decreases, but where there is moisture enough even there the ferns often constitute a striking, if not a predominant, portion of the Flora. But not only do Cryp- togams prevail frequently to a very great extent in number of species, but in number of individuals also. The myriads of acres covered with reindeer moss in the North of Europe and Asia, produce a number of individual plants of the same species far exceeding anything that can be compared in that respect amongst Phenogams, In our own country, Pteris aquilina often excludes almost every other vegetation. 54. The degree in which some Cryptogams are capable of resisting long-continued drought, is most remarkable, though growing on rocks exposed to a burning sun; witness the Lichens, whether crustaceous or foliaceous, which revive with the first shower as perfectly as a dormouse waking from its winter’s sleep, and the same applies to many mosses, And this, be it observed, is totally different from the case of bulbs, which grow in plains which, during a portion of the year, are arid deserts, and burst forth with the first appearance of the periodic rains; for, in the one case, the whole plant is exposed, and in the other, a body which performs the functions of a seed, the centre of which is pro- tected by the surrounding envelopes. from the drying action of the air; while many bulbs have the additional protection of a greater or less depth of soil. In these cases, it may be observed that the cells are laden with starch or bassorine; 68 INTRODUCTION TO CRYPTOGAMIC BOTANY. and many of those Cryptogams which are most capable of enduring drought, as Lichens, are precisely those into whose composition a larger proportion of amylaceous matter enters. The spores, too, of some, as of certain species of moulds, are capable of resisting the temperature of boiling water, a fact which would be almost incredible, were it not confirmed by repeated observation. Itis true that some seeds of Pheno- gams may be immersed in boiling water without losing their power of germination, but these are seeds with thick imtegu- ments, through which the heat does not penetrate with sufti- cient rapidity to make a short immersion fatal. I have, myself, recorded an instance of the germination of thousands of grape seeds after three immersions in boiling water; and Dr. Lindley ‘mentions the curious fact of raspberry seeds growing after being boiled for jam, in which case, if the sugar were really boiling, the temperature would be above the boiling point of water. It is manifest that in neither case were the observations sufficiently exact, as, indeed, too often happens where they are not founded on direct experiment. 55. Cryptogamic plants are divided naturally into two great classes, viz., those which approximate more nearly, by reason of their foliaceous appendages and green tint, passing into shades of red or purple, to Phenogams, and which exhibit something more or less remotely resembling the formation of the embryo in Phznogams, as Ferns, Mosses, Liverworts, &c. ; and those which are leafless, very rarely of a vegetable green, and whose fructification consists either of cells separated from the tip of certain privileged filaments, or formed within their cavity from the protoplasm, which are at once fertile, without any approach to the production of an embryo. The latter, as more simple, will claim attention first. Indeed, the differences between these two great divisions are so prominent, that the doubt, perhaps, is whether they should be associated under one name, for they are as distinct from each other, as the former are from Phenogams, to many of whose attributes they approach in Clubmosses, and Mursileacew. Many names have been proposed, to distinguish them, and of these, as the least liable to objection, I shall take those of Acrogens and Thallogens, proposed by Lindley, in the Vegetable kingdom, which are, in INTRODUCTION TO CRYPTOGAMIC BOTANY. 69 fact, more or less closely, those of Endlicher and Brongniart. The former, then, will be designated as Acrogens, without, however, supposing too strictly that new matter is deposited only at the extremity, and the latter as Thallogens (plants in which there is a fusion of root stems and leaves into one general mass) which is equivalent with that of Amphigene, of Brongniart. When these two grand divisions are established, we shall be enabled to form a much more clear and precise notion of the objects under consideration. There is no diffi- culty, for instance, in framing some general conception which shall embrace, in the same bird’s-eye view, the smallest moss and the most gigantic tree fern, while nothing but a complete ignorance even of the outward characters of the fruit will con- found in the same class, the most frondose Lichen or Alga, with the least frondose Jungermannia. 56. The word Acrogens, as observed before, has been applied to the whole race of Cryptogams. There is no question about its more general application now. Though very insufficient in the first instance, it may be proper enough when used in a restricted sense. In the sequel, I purpose to give such tabular formule as may assist the student in taking a general view of the subject, and of obtaining some insight into the divisions into which Cryp- togams are naturally divisible, but it will be well, as we proceed, to contrast the prominent distinctions of parallel groups. Crypto- gams,then, in the first instance, are divisible intotwo great groups: THALLOGENS.—Seldom herbaceous or provided with foliaceous Al % I. appendages ; foliaceous appendages, if present, = s , = destitute of stomata. Spores rarely producing a prothallus ; (and, if so, giving rise to a a line Sixlgecond order of spores, germinating at definite 3 “points. | Spermatozoids not spiral.* E Acrocrens.—Mostly herbaceous, and provided with distinct, a as often stomatiferous foliaceous appendages. o Wet SM ts Spores, for the most part, producing a pro- : Pa tos fi yal thallus, or if not, complicated fruit by means- ‘ of the impregnation of an embryonic: cell. Spermatozoids spiral.+ * Itzigsohn, however, asserts that spiral Spermatozoids exist in Spirogyra arcta and Cladosporium. Hedwigia, 1852, 1855. + It is to be observed that those Thallogens which have the green 70 INTRODUCTION TO CRYPTOGAMIC BOTANY. tint of Phenogams, are generally very simple in their structure, and of these the species which are most fruticose in habit, as Caulerpa, consist of a single cell, however large and complicated the plant may be. In some of the finer Alge alone, organs exist, comparable with leaves for their nervation and expansion. The prothallus, when produced, ends in the formation of spores, analogous with pollen grains, and with the spores of Acrogens, and homologous with the sporophores of Hymeno- mycetous Fungi. The embryo cell in the more typical Acrogens gives rise to an analogue of the embryo in Phznogams, but in the less typical, in which there is no prothallus, to fruit analogous with stamens. The produce of the spores, though themselves generated after the same type, is so different, that all comparisons are attended with great diffi- culties. CLASS I—THALLOGENS. Lindley. Crypropuyta, Li.—Ananpra, Lk—Apruyiim, D.C., Lindl—*Homo- NEME®, Bartling, Fries—Homorcana Sporirura, Scheltz.—Tua- LopHyta, Hndlicher—Proropuyta, Perleb—Ampuicens, Brongn.—- ACOTYLEDONEX, Ag. CELLULAR, rarely herbaceous, plants for the most part des- titute of a distinct stem with foliaceous appendages, which, if present, are void of stomata ; fruit either naked, or in the form of distinct organisms, which produce spores at the tips of certain privileged filaments, or sporidia from the organiza- tion of their endochromes; more rarely arising from the mere subdivision of the component cells. Spores very rarely producing a prothallus, and if so, giving rise to a second order of spores, which germinate at definite points. Spermatozoids, very rarely, if ever, spiral, furnished with flagelliform pro- cesses, or destitute of such processes, and resembling ordinary spores; in some cases merely represented possibly by minute deciduous sporiform cells. As before, the several names which have been applied will nearly give the characters : 1. Cellulavia, Homonemecee, Homorgana. 2. Aphylle, Thallophyta, Amphigene. 3. Acotyledonec. 57. Itis, perhaps, impossible to comprise within the limits of a few words, a satisfactory definition of productions, which differ so greatly in character and general appearance, as the extreme * There is certainly a distinction of root and stem in many, even of the simplest Thallogens. The root in Alge is often a mere holdfast, but in other cases it penetrates into the soil, and absorbs nutriment, and the same may be said of some of the simpler Fungi. In the higher Fungi, this opposition is still more evident. 72 INTRODUCTION TO CRYPTOGAMIC BOTANY. forms which claim a place in this grand class. If the simplest cellular alge, as for example, Scenedesmus obliquus (Fig.16, a), a QW, 4 i ti FARE Fig 16. a. Scenedesmus obliquus, Ktitz, magnified from specimens gathered at King’s Cliffe. b. Lessonia fuscescens, Bory., reduced from Dr. Hooker’s figure in Flora Antarctica. be compared with Lessonia (Fig. 16, b), or Macrocystis ; a Gymnosporium (Fig. 17, a), with an Agaric or Cordyceps (Fig. 17,0) ; or finally the Leprarioid Sporidesmium (Fig. 18, a) INTRODUCTION TO CRYPTOGAMIC BOTANY. 73 with a Cenomyce (Fig. 18, b), for there are no perfect Lichens which will not come under one general type of fructification, we shall at once see that it can only be by straining words beyond a. Spores of Gymnosporium fulvum, Berk., magnified from specimens received from Mr. Lea, b. Cordyceps Sinclairti, Berk. in Fl. of New Zeal., p. 338, from spe- cimens communicated by Mr. Gourlie, their proper meaning, that a technical character can be framed which shall comprise all. And more especially when we reflect, that many of the lower Algex consist apparently of a succession of divisions of a few primeval cells, without any distinct thallus, however obscure ; that others are mere ramifications, or pro- longations of a single thread; while others, again, are almost as complicated as higher Cryptogams, and approach them in the development of a distinct stem with foliaceous appendages, and these frequently furnished with nerves and veins, so as to simulate those of higher plants. Simple as the lower types are, we should be much deceived if we supposed that the same simplicity pervaded the whole class. A glance at the figures of Tulasne and Kiitzing, representative of Truffles and the larger Alge, will be sufficient to dispel such a notion. The dignity of these bodies is in truth not to be measured by the more ignoble species, some of which, however, on examination, prove far less simple than was once supposed. If there were any truth in the notion, that a slimy matter is pro- v4 INTRODUCTION TO CRYPTOGAMIC BOTANY. duced in damp places, under certain chemical conditions, which gradually becomes organised, and then contains Fig. 18. a. Sporidesmium Lepraria, Berk., magnified from a specimen com- municated by Mr. Borrer. b. Cladonia cornucopioides, Scher. Moug. No. 752, nat. size, c. Roccella fuctformis, D. C. var. from Valparaiso, nat. size. granules, which, according to the predominance of certain phenomena of temperature, light, electricity, &c, give rise indifferently to Alge, Fungi, or Lichens, there would be INTRODUCTION TO CRYPTOGAMIC BOTANY. 75 no difficulty in admitting the vulgar notion, that Poly- porus squamosus is a mere product of the sap of the tree on which it grows, or even that plants and animals, how- ever complicated, may spring from decomposed or decom- posing organic matter; especially if the notion be extended still farther, as it is by many German authors, so as to include the possibility of this same protoplasm (urschleim) being equally capable of giving rise to the lower animals. The ground, however, is fast sliding from beneath the feet of such philosophers ; organisms which once were supposed to be so simple, are found to be, in fact, somewhat complicated ; the presumed distinctions of animal and vegetable life are not so certain as was imagined by older physiologists; and in consequence, when a Protococcus (Fig. 8, 9), in one stage of growth produces veritable spores, and in another bodies endowed with apparently voluntary motion, by means of flagelliform appendages, we are not at once to presume that such effects take place indifferently, but should conclude, rather, that they are bound up in the very nature of the production, and that the two kinds of bodies are no more organisms gene- rically or specifically distinct from the parent, than the male offspring is from the female in the animal kingdom. 58. Thallogens consist, in most cases, of cells, modified in form, and in the nature and chemical condition of their walls, but never accompanied by spiral tissue, except in the organs of fructification, where its office seems to be principally the gradual dispersion of the reproductive bodies. Whatever aération may take place in their substance, it is at least, not conducted by spiral vessels or by analogous ducts, but by large intercellular passages, or the void space between the component filaments, where the cells, as is very frequently the case, are drawn out into threads. They are entirely destitute of true stomates, though in many cases, from their spongy nature, the air has free access into their substance. In many, however, the inner cells must be cut off from communication with the atmosphere, except by endosmose, and in the aquatic species, external apertures are scarcely to be expected. Cladonia retipora (Fig. 19) presents a frond remarkable for its perforation, and some other Lichens in 76 INTRODUCTION TO CRYPTOGAMIC BOTANY. a less degree. In most species of Lichen, the outer walls are densely compacted and cartilaginous, so as to present some diffi- culty of penetration in that direction, except from accidental fissures or normal ruptures, while the spongy base more readily Fig. 19. a. Cladonia retipora, Flérke, nat. size. b. Portion of stem magnified to shew the porous structure. From an Australian specimen given to me by Sir W. J. Hooker. absorbs moisture. Though even in the largest Algce there is no wood, properly speaking, still the stems sometimes acquire considerable dimensions, and even shew concentric zones (Fig. 15), which arise, probably, from distinct periods of growth and rest, as in Dusycladus claveformis, and in those Poly- port whose flesh exhibits similar markings. 59. A second mark of distinction is, that they have no true leaves. As was before stated, they have foliaceous expansions of various kinds and forms, resembling, in some cases, true leaves very closely, and in some degree, perhaps, performing their functions, at least, so far as exposing a larger surface to the light, and the medium in which they grow, and from which they derive their nutriment. The processes of absorp- tion, nutriment and aération are frequently, however, in these plants, altogether confused, the seeming roots being little more than grappling threads, intended to fasten them in their proper place, and enable them to withstand the force of wind and waves. In some cases, indeed, amongst Alge and Lichens, and very generally among Fungi, the rootlets may INTRODUCTION TO CRYPTOGAMIC BOTANY. 77 imbibe nutritious matter from the soil or matrix, but this is very far from being a universal attribute. When fronds are present, they are seldom disposed symmetrically, except they take the form of threads; in which case they exhibit, at times, the most exquisite arrangement, so as to make them objects of much admiration, and some of the most symmetrical occur amongst species of inferior dignity. The symmetrical arrangement of the subulate processes in Chara, does not come under the present head; for the nature and mode of origination of the spermatozoids associates these plants evidently in the second great class of Acrogens. 60. A third common character is afforded by the nature of the fruit. In a few simple cases the process of fructification consists merely in the division of the mother cell; but, in general, the reproductive bodies are due to the thickened end of certain of the component threads, which ultimately separates and forms sometimes a single spore, consisting of a double cell wall with its endochrome, or of a multitude of endochromes produced by division of the cell; in other cases, however, the endochrome of the cell itself (which is then called an ascus), becomes organised without any change of the inner membrane, and presents a definite or indefinite number of distinct repro- ductive bodies. In many instances, both the spore-bearing threads and asci are naked; but very often, they are either permanently contained as a lining in distinct organisms, or at length exposed to the open air; sometimes, they form a tuft, springing from the base of the fructifying cavity, after the fashion of a central placenta. 61. Another distinctive feature consists in their various modes of fructification, in the same individual species. This has long been notorious in the case of the more important Alge, and it is daily becoming more evident amongst Fungi, and will, pro- bably, be extended to the whole group. It is difficult at pre- sent, in the absence of direct observations, to say precisely what is fruit and what is not, asit appears that in many cases the secondary form may be representative of male organs, if not functionally such. Certain it is, at least from the observations of Thuret, that the spermatozoids of Fuci, which our countryman, 78 INTRODUCTION TO CRYPTOGAMIC BOTANY. Carmichael, was the first to discover, do really perform the office of fecundation. Amongst Fungi, in many cases, the secondary form germinates equally with the primary, but then there is sometimes added a third, or even a fourth or fifth.* (Fig. 20). Where there are true spermatozoids, there is often more than one form of reproductive granules, though both, possibly, may not receive impregnation. Fig. 20. Spherotheca Castagnei, Lév. a. Threads of mycelium, with some of the joints turned into pye- nidia. 4. Granules germinating within ordinary moniliform cells. ce. Pycnidium and its contained stylospores. d, Ascus, with sporidia. Berk. in Tr. of Hort. Soe. vol. ix. p. 68. 62. The question now arises, into what principal groups are these bodies naturally divisible. Now, though the matter is not without exception, it must at once strike any one who observes them collectively, that certain differences exist, order- * In Erysiphe, there are no less than five different forms of fruit; the moniliform threads on the mycelium; the asci in the sporangia ; the larger stylospores in other sporangia; the smaller stylospores in the pycnidia; and the separate sporules sometimes formed in the joints of the necklaces. INTRODUCTION TO CRYPTOGAMIC BOTANY. 79 ing them into three very natural groups, according as they inhabit the water, the earth, or the air. The great tribes of Conferve and seaweeds, for instance, with very few exceptions, are entirely or periodically submerged, and live at the expense of matter imbibed from the medium in which they grow. The Lichens, though with more numerous exceptions, grow on bodies from which they can derive no nutriment, but depend upon supplies which come from the surrounding air, the ex- ceptions of aquatic species being very few indeed ; while, on the contrary, the Fungi are altogether dependent upon their matrix, are frequently parasitic, and are not unfrequently con- fined to a single species, genus, or natural order of Phenogams. The aquatic species are as rare as in Lichens, and more so than the truly terrestrial among Alge. That the three groups are natural, it is quite impossible to deny. The question is, whe- ther they are groups of precisely the same importance; a question, the difficulty of which has been felt by most authors who have treated on the subject. Linneus, for instance, and Jussieu, considered Lichens as forming a part of Alge, in which they are followed by Fries, one of the best authorities upon Cryptogams, and, above all Botanists, possessed of that tact which grasps the real affinities of organisms, even before their structure is accurately known. It is true that two of the groups are easily and naturally divisible into more, but the question is not as to subordinate groups, but as to the larger and more comprehensive divisions. The real difficulty, indeed, lies with the Lichens ; but this is far less than it was formerly, since it has been proved that, in essential structure, and in their secondary fruit, whether of sexual importance or not, they are most closely related to Fungi. For my own part, I am of opinion, that at any rate the nearest alliance of Lichens is not with Alge, but with Fungi; there is not a single instance amongst Alge, of ascophorous fruit, for such genera as Lichina, Mastodia, &c. are evidently allied to Collema, and, though the thallus of Collema is nearly identical in struc- ture with Nostoc or Hormosiphon (Fig. 21), I consider this merely an osculating point; the true mode of increase in Nostoe, which is now well known, connecting that genus rather 80 INTRODUCTION 10 CRYPTOGAMIC BOTANY. with Palmellew, than with higher forms. It is possibly, after all, a mere matter of analogy, though some will insist that true species of Nostoc are capable of being developed into Lichens. Hormosiphon arcticus, Berk. a. Plant, natural size. b. Portion of do., magnified. ce. Thread of spores, with its gelatinous envelope. From a specimen gathered near Beechy Island, by Dr, Sutherland. 63. A point, however, of considerable importance is this: that, both in Alge and Fungi, there is a complete series of forms from beings of extreme simplicity of structure, consisting of merely one or two cells from which more complicated organisms gradually diverge, ending in the most perfect Sea- weeds and Fungi; while in Lichens, the very simplest display perfect fruit, resembling altogether that of Fungi, insomuch that, of many species belonging to either group, it is almost impossible, in the absence of crust, to say whether we have a Lichen or a Fungus before us. It seems, therefore, far prefer- able, to regard Lichens as forming a great group, co-ordinate with Fungi, but of an inferior dignity to the parent group, or to Alge. The only acute difference that can be pointed out be- tween Fungi and Lichens, is the presence of green bodies, called gonidia, in the latter (reproductive bodies produced from the tips of certain internal threads), and this even ceases in some of the more obscure Verrucarie, and in epiphyllous spe- cies. It is impossible, in fact, to point out any real difference between Asterina, and such species of Strigula as S. Babing- toni, and it must be remembered, that Fungi, with a similar habit, take their first growth, like Strigula, beneath the true INTRODUCTION TO CRYPTOGAMIC BOTANY. 81 cuticle, as Asteroma Rose. It is true, our difficulties of defini- tion have increased; and if Lichens are to be considered as of equal dignity with Fungi, both belonging to one large group, there is a necessity for giving that group a distinctive name. In such matters, systematic effect, or neatness of character, is not to be studied, but the real affinities of plants; and if a closely allied group be separated too acutely, the affinities will some- times vanish from the view. I shall therefore, at all risks, con- sider Algals, or Hydrophytes, as forming the first grand group; and for the second, propose the name of Mycetals, comprising the two received alliances of Fungals and Lichens. The Thallogens will then stand thus: A. ALGALES. Cellular flowerless plants, for the most part without any proper roots or mycelium, living, with rare ex- ceptions, entirely in water, and imbibing nutriment by their whole surface, from the medium in which they grow. B. Mycerarrs. Cellular flowerless plants, at first, fur- nished with a mycelium, very rarely immersed, deriving nutri- ment from the matrix, or from the surrounding air. a. Fungales. Hysterophytal or Epiphytal Mycetals, deri- ving nutriment, by means of a mycelium, from_the matrix, never producing from their component threads, green bodies resembling chlorophyll (gonidia). b. Lichenales. Aérial Mycetals, deriving, for the most part, nutriment from the surrounding media ; producing, from the component threads of their thallus, abundant gonidia. Deriving nutriment from 5 the water in which they . 3 are submerged. 4 2 g Hysterophytal or Epi- = RS phytal; nourished by the | = matrix, never producing 2 % Deriving nutriment from e presenta B 4 the matrix, or the sur- z pase aera a < AGrial; nourished by air 8 and not by the matrix, Ss producing gonidia. 82 INTRODUCTION TO CRYPTOGAMIC BOTANY. 64. Fries has long since pointed out that there is no certain distinction between Lichens and Fungi, except the presence in the former of green globules, resembling grains of chlo- rophyll. Such distinctions are not without real importance. If Vaucheria (Fig. 22), and one of the parasitic species of Fig. 22. Vaucheria submarina. Magnified. From specimens gathered at Weymouth. Botrytis, such as B. parasitica (Fig. 23), be compared together, Fig. 23. Botrytis parasitica, P. With spore, more or less magnified, from specimen gathered at King’s Cliffe. INTRODUCTION TO CRYPTOGAMIC BOTANY. 83 I know of no external distinction,* except their place of growth and difference of colour. The definitions of the three groups, as given by Agardh and Brongniart, will not hold good in numberless instances. The definitions given above, will, at least, point out the main distinctions; but it is probable that the rooting threads of Botrydiwm (Fig. 24), Caulerpa, and of many of the calcareous Algw, do absorb nutriment from Fig. 24. Botrydium Granulatum, magnified. the soil, and, perhaps, for the reason that they are frequently exposed to the dry air, and would, therefore, wither without such a provision, or are so incrusted with lime as to render nutriment through the surface precarious. It can scarcely be supposed that Lichens never derive any nourishment from their matrix, because certain species grow only upon certain kinds of rock, and some burrow into the matrix ; still, even in these cases, it is clear that the principal part of their nutriment is not imbibed by the spongy tufts, or scattered filaments on the under side of the thallus. * There are, indeed, recondite differences, as will appear hereafter, some of which have only lately been ascertained. 6 * St INTRODUCTION TO CRYPTOGAMIC BOTANY. ALLIANCE I. ALGALES, Lindl. Aten, Juss. D. C., Agardh, &c—Tuaarassiopnyta, Lam.—Hyprorayta, Lyngb.— Hyprovematem, Nees.— Hyproruyca, Fries.— Puyciizs, Montagne. CELLULAR flowerless plants, without any proper root or myce- lium, living, for the most part, entirely under water, and im- bibing nutriment by their whole surface, from the medium in which they grow. Propagation of various kinds, sometimes by the mere division of the endochrome, sometimes by spores or zoospores, formed from the endochrome, or by the mixing of two endochromes; sometimes by the joints of privileged threads, either naked, or contained in especial organs, and oc- casionally of two orders. Sexes often distinct on the same or different individuals; impregnation, by means of spermatozoids furnished with one or more flagelliform appendages, but obsolete in the lower species ; spermatozoids very rarely, if ever, spiral. 65. The objects which constitute this large family, are extremely variable in appearance. Many can scarcely be ex- amined as regards their external characters, without the assist- ance of a magnifying glass; while others form subaqueous forests, or float in dense masses many miles across, the indi- vidual plants of which are sometimes one hundred feet or more in length ; some are devoid of all beauty, while others are, perhaps, the most elegant objects in nature, alike attractive in form and colouring ; added to which, the markings in the sili- ceous shells of one main division are so exquisite, as to consti- tute them the most admirable objects for the microscope. 66. The first question which occurs in the consideration of the subject generally, is where the limits of the order are to be sought. It is very clear, that many of the lower species are upon the very confines of the animal kingdom, and in conse- quence, many undoubted Algz have been referred by authors to that division of organised beings. There was, indeed, some INTRODUCTION TO CRYPTOGAMIC BOTANY. 85 excuse for the earlier observers, if they made mistakes, and preconception easily gave rise, under the imperfect magnifiers, some twenty-five years since, to reports of structure which had their existence only in the imagination of the writers. When Dujardin had once called in question, and with great propriety, many of Ehrenberg’s observations, with regard to undoubted animalcules, there was not much hazard in doing the same with respect to Diatomaceew and Desmidiacee (Fig. 7). A practised observer, with good modern instruments, would now scarcely entertain a doubt upon the subject, when such objects as the eggs of Aplysia and Gnats (Fig. 12), not to mention such Polypidoms as Alcyonidiwm, are placed before his eyes, though they, and many similar productions, were formerly registered as vegetables. It is true, that in some cases, motion may exist, and that apparently, volun- tary ; but it is now well known that such motion is by no means a certain indication that a given body does not be- long to vegetables. In the article Vaucheria clavata, of the Gleanings of British Algw, so long ago as 1833, I drew atten- tion to the possibility of animal and vegetable life existing at different stages of growth in the same individual, and what is stated there, requires but little modification now, even after the discoveries which have since been made respecting zoo- spores and spermatozoids. It is precisely at such osculating points that these complex phenomena may be expected ; and as life, whether animal or vegetable, is only a phrase, formed to express certain phenomena, the plain fact is, that similar phenomena are exhibited by animals and vegetables, though such phenomena may be confined to a very small period, compared with the whole range of existence. The degree of volition, if such it may be called, is extremely low, and may be unattended with any consciousness, and merely be the in- dication of certain exigencies of the minute body for light, or other necessary elemental conditions. When, however, it is said by the German naturalists; that organised matter has a tendency to be converted into organised bodies, a proof is required on the part of the assertors, that every source or possibility of error has been removed, before they can challenge even a state 86 INTRODUCTION TO CRYPTOGAMIC BOTANY. of philosophic doubt. A careful examination of Kiitzing’s papers, in Linnea, vol. 8, 1833, and much more of his prize essay, will show a multitude of such loopholes; and, but for his acquaintance with species, they never would have com- manded so much attention as they have; and if Kiitzing’s observations are suspicious, still more assuredly those of Reissek, who professes to have witnessed the transformation of chlorophyll into Alge, and pollen grains giving rise to moulds laden with spores, which spores, when placed in water, produced Confervoid plants filled with chlorophyll, and copulating with one another. Nay, more than this, he reports the metamorphosis of pollen cells into animals, belonging to Ehrenberg’s genus. sta- sia, and that the contents of the pollen cells also produced plants and animals. From the smaller particles, originated Bucteric, Vibrios, and Conferve, from the larger green globular monads.* While we doubt not the fact of his obtaining the germination of pollen grains apart from the stigmatic moisture, as in the parenchym of plants, sometimes belonging even to a different natural order, a fact which has no unimportant bearing on some physiological questions, respecting the impregnation of the ovules of Pheenogams, under certain anomalous conditions, it cannot be allowed for a moment, with every deference to the fidelity of the author, that his investigations were conducted in such a way as to challenge: belief. I shall, on this subject, beg leave to reproduce the passage from the Annals of Nat. Hist., v. xiv. p. 434, which has been quoted by Dr. Lindley, in the Vegetable Kingdom, because I cannot express my sentiments better than I did there.t ‘“ As far as I understand what I have read upon the subject, I cannot help remarking first, that the observations cannot be considered conclusive, apart from all * This is from a mere verbal report by Reissek, in Bot. Zeit. July 19, 1844; but a full account with figures has since been published. + The passage is in a review of Kiitzing’s Treatise, Ueber die Ver- wandlung der Infusorien in niedere Algen-Formen. Nordhausen, 1844, with an especial view, at the same time, to his larger Prize Treatise, Die Umwandlung niederer Algen-Formen in héhere so wie auch in Gat- tungen ganz verschiedener Familien und Klassen héherer Cryptogamen mit Zelligem Bau. Haarlem, 1841. INTRODUCTION TO CRYPTOGAMIC BOTANY, 87 prejudice either way, till a certain number of bodies, ascer- tained to be precisely of the same nature, be isolated, and the changes of these observed, with every possible precaution, to avoid error. At present, it seems to me that there is not ‘by any means sufficient proof that the objects in question really arise from germs of the same nature. The second remark I would make is, that there appears, too often in treatises of this description, to be great indistinctness as to the notion of what a species really is. We know that in the course of development, higher bodies go through a vast variety of phases, which resem- ble closely true substantial species which have arrived at their full development, but we are not therefore to suppose that in passing through these phases the production has really con- sisted of such a number of real species. In the Agardhian sense this may be true enough, for when he pronounces the vessels and cells of phanogamous plants to be Alge, his rea- soning appears to be, however strongly he expresses himself, merely that they are representatives of Alge, and resemble them in structure. I would remark, also, that the real difficulty of the case does not depend on the question as to the difference of animal and vegetable life. These evidently in certain parts of the creation are so intimately combined, that it is quite im- possible to say where the one ceases, and the other begins ; and there is really no reason why we should be incredulous as to the possibility of the same object being at one time endowed more especially with animal, and at another with vegetable life. Late observations on the reproductive bodies of some Alge show that their motion is produced by vibratile cilia, exactly in the same way as in certain animals. But it is exceedingly difficult to imagine the transformation of. one real species into another. The same species may assume a vast variety of forms, according to varying circumstances, and it is highly instructive to observe these changes; but that the same spore should, under different circumstances, be capable of producing beings of an almost entirely different nature, each capable of repro- ducing its species, is a matter which ought not to be admitted generally without the strictest proof. Observations made with care on isolated individuals, and not on a common mass, which 88 INTRODUCTION TO CRYPTOGAMIC BOTANY. can scarcely be otherwise than more or less heterogeneous, could not fail to be instructive; and might lead to results which, if they did not confirm the views so commonly entertained in Germany, would have an influence on science which it is diffi- cult at present to appreciate.” ’ 67. For a long time, motion, as said above, especially if it had the semblance of being voluntary, was esteemed a certain mark of discrimination between the animal and vegetable kingdoms. Mere molecular motion, or that due to evaporation on the field of the microscope, was therefore often brought forward as an argument for the exclusion of many vegetables from their proper position in the organised world. And there is the same disposition occasionally now.* To take the example alluded to before of Ulothria (p. 18), and there are many similar ex- amples, as Conferva glomerata, Aehlya prolifera, &c., the articulations give rise, from their protoplasm, to cells termi- nated by delicate cilia, by means of which, they move about apparently at will, till the appendages lose their activity, and the body sinks, becomes fixed at one end, and at the other produces a new individual precisely like that from which it originally sprang. Sometimes, as in Stilophora rhizodes,+ there are two distinct formations of such bodies, from distinct parts of the plant, both of them equally endowed with motion, and both equally capable of reproducing a plant like the original, though not precisely by the same series of phenomena. These bodies are, moreover, so like certain Infusoria, as Disel- mis, Dujard., that without ascertaining the changes which take place during the course of their existence, it would be * See a notice of the motions of Navicula Vichiensis, Petit, by M. Petit, in Montagne’s Sylloge Gen. et Spec. Crypt., p. 471. + Thuret, Recherches sur les Zoospores des Algues, Partie 1, tab. 28. In other cases, doubtless, two kinds of Zoospores are produced, as in Leathesia and Mesoglwa, as they have the two organs called Oosporangia and Trichosporangia by Thuret. The Zoospores of the latter are rather larger than the former. In Cutleria, there are bodies answering to autheridia, producing apparently Spermatozoids, but though they do not germinate, they do not seem to have the power of impregnation. They appear, in fact, to be a distinct transition from Spermatozoids to Zoospores.— Thuret, 1. c. tab. 26, 27, 31; Partie 2, tab. 1. INTRODUCTION TO CRYPTOGAMIC BOTANY. 89 impossible to assert that the two were only distantly related. We have here, then, indications of two distinct stages of ex- istence, the first, animal, and the second, vegetable. But fur- ther experience shows us that the organism which produces these active cells, is no doubtful being, a mere Polypidom, as it were, but a real vegetable, for in other Algze, we find two sorts of organisms, the one of which produces from its bosom ordi- nary spores, the other bodies precisely like the zoospores of the Ulothrix. We might expect, from the perfect resemblance and identity of origin of these zoospores and spermatozoids, for both arise from the protoplasm of the cells, that these also would, after moving about, subside, and reproduce the species. But this is not the fact; like spermatozoa, their activity is of short duration, and capable of being destroyed at once by iodine and other chemical bodies; when this activity has ceased without the presence of any such injurious substance, the bodies acquire no attachment, and do not grow into a thread, but gradually decay. The spores, on the other hand, make no progress, and retain their vitality but « short time if kept alone, but if the two bodies are mixed a. Portion of a thread of Vaucheria sessilis, Lyngb., shewing a spore cell and an antheridium. The protoplasm of the spore cell is collected towards the centre of the cell, which is filled with jelly, the apex has ruptured, as also that of the antheridium, and the spermatozoids are entering through the aperture. b, A spore perfectly formed, which, since impregnation, has acquired a membrane. ; ; ce. Spermatozoids. All more or less magnified. From Pringsheim’s memoir. 90 INTRODUCTION TO CRYPTOGAMIC BOTANY. together, they soon show manifestations of vegetation, and re- produce the species. We have, therefore, spores vivified by the impregnation of bodies, corresponding in their functions with the spermatozoa of animals, and to some extent in their genesis; and the homologous bodies in the Ulothria or Con- ferva, are no more proofs that these genera belong to the animal kingdom, than that Fuci should be excluded from vegetables, because of the animal indications of their sperma- tozoids. 68. Owing to this exact resemblance between the spermato. zoids of higher Algz, and the motile spores of many lower in the scale, some doubt has been conceived as to their real functions: but the direct experiments of Thuret have set such doubts at rest. In some of the simpler Algze, however, the development of the spermatozoids, and their effect in the vivification of spores, is more easily traced than in the Fucotdew ; and, accordingly, we have a most valuable series of observations on Vaucheria (Fig. 25), by Pringsheim, to whose kindness I am indebted for the possession of his treatise.* The species prin- cipally concerned in the investigation was Vaucheria sessilis, an Alga consisting of a single branched and elongated cell, without any dissepiments before the formation of the fruit. Two little contiguous swellings appear on the side of the thread, one of which rapidly elongates and becomes curved, and the other meanwhile, assumes a more or less globose form. A dissepiment is then formed in the middle of the curved process, which is soon filled with minute oblong spermatozoids, furnished on one side with two filaments, by which they move. Meanwhile, a dissepiment has also formed at the base of the globose body, whose endochrome alters its appearance, a portion of the globule turned towards the male organ, swelling into a little beak ; a part of the wall then gives way; the endochrome parts with some of its mucus, and a passage is left open for the entrance of the spermatozoids ; the endochrome after impregnation soon acquires a membrane, and, ultimately, the whole is condensed into a spore, which * Monatsberichte der Kénigl, Ak, der Wissenschaft, Berlin, 1855. INTRODUCTION TO CRYPTOGAMIC BOTANY. 91 bursts through the integuments and becomes free. In (Cdogo- nium, in like manner, an aperture is formed for the admis- sion of the spermatozoids to the endochrome, which then acquires an integument, and becomes a spore, while in Bul- bocheete, the same purpose is effected by a little fissure ; the spore of the latter falls out after impregnation and then elon- gates, the endochrome dividing at length into four, each por- tion of which gives rise to a zoospore, furnished with two bundles of flagelliform cilia. 69. Both in Hdogoniwm (Fig. 26, a, c) and Bulbochete (Fig. 26, b) little bodies* are formed on the walls of the spore cell, which seem, at first, like germinating spores. They acquire one or two dissepiments, and then discharge their contents from the ruptured apex. These, in all probability, are the antheridia. Their existence has only very lately been published, but they have been known some time to close observers. I have a sketch from Mr. Thwaites, in a letter dated April 22, 1846, which is here reproduced (Fig. 26, a); and I also received a mounted specimen, at the same time, in which the bodies are some- times more numerous than in the figure. Here and there Fig. 26. a Fertile joints of the @dogonium with Antheridia, from a sketch by Mr. Thwaites, compared with a mounted specimen, April 18, 1846. b Spore case of Bulbochete crassa, Prings., with Antheridium, from a mounted specimen from Mr. Thwaites, May, 1847. e Zoospores of @dogonium vesicatum, after Thuret. * Thuret has evidently figured one of these, I, c., tab. 19, fig. 9, though he was not aware of its nature. These little bodies forcibly remind one of the processes produced on the spores of Dacrymyces deliquescens, Dub., as mentioned above, p. 44. 92 INTRODUCTION TO CRYPTOGAMIC BOTANY. they are produced on other joints, as well as on those which give rise to the spores. It is curious, in two such closely allied Alge as Vaucheria sessilis and V. clavata, to find the fruit so very different. The spore of the former is per- fectly inactive, while that of the latter revolves by means of delicate cilia covering its whole surface. It is clear, then, that we must not, in these lower Cryptogams, attach too much importance to motion. Neither in these cases, nor in similar organisms in the animal world, is there the slightest reason to believe that this motion is effected by any system of muscles. Its real cause is, at present, beyond our powers of discovery. 70. Dr. Itzigsohn has figured in Hedwigia, 1852, p. 7, the spermatozoa of Spirogyra arcta as produced within little cells, after the fashion of those in mosses, and forming a little spiral, with a thickened extremity. Whether there is any mistake in this or not must be left to future observations; the structure in other cases, which he mentions as probable, viz., Vawcheria, Gdogoniwm, Bulbochete, and Cladophora, is, where it has been ascertained, certainly very different, and resembles, more or less, that im the higher Algz, or the bodies are not sperma- tozoids at all, but zoospores. 71. It is to be mentioned, moreover, in connexion with the subject, that different Algz in different stages of growth wear so different an appearance as to seem to indicate totally diffe- rent affinities. Lemanea torulosa, for instance, for a long time has all the appearance of a Conferva,* in which condition its nearest affinities could not so much as be suspected; the earliest stages of Porphyra resemble a Bangia, and so of other cases. This alone may lead to perplexity in such determinations, but much more the fact that it is very doubtful how far many of the supposed Algz, such as Glewoclapsa, are autonomous species. Where a plant bears fruit, and is reproduced by that fruit, as for instance, Protococcus pluvialis (Fig. 8, 9), there can be little doubt that a species is true; but where all the propagation is a simple repetition of the division of the endochrome, as in Gleocapsa, there is some room for doubt. Mr. Thwaites, in the * Linn. Tr., vol. xx. p. 399. INTRODUCTION TO CRYPTOGAMIC BOTANY. 93 course of his investigations, was led to suspect that many of these lower Alge, however beautiful and interesting as micro- scopical objects, were not autonomous; many seemed to pass into each other by intermediate forms, and others were so con- stantly the attendants of others, as Palmelle of Seirosiphon, that he was led strongly to suspect some very close and inti- mate connexion; and this is formally enunciated in a late number of the Botanische Zeitung, Jan. 5,1855.* M. Sachs professes to have seen a Wostoc generated on the surface of Collema bulbosum, and a Gleocapsa on that of Cladonia pyai- data.t It is to be observed, however, that he is not sure whether the Vostoc has arisen from the spores of the Collema, or from its gonidia, but he speaks positively as to the origin of a Gleocapsa from the threads of the lichen by the trans- formation of a gonidium. When the Glwocapsa is once formed it increases rapidly, forming a gelatinous mass, entirely distinct from the Cladonia. Supposing this to be true, it is not a transformation of a lichen into an Alga, but the supposed Alga is a mere condition of the lichen; and if all species of the genus belong to the same category, the genus must be erased from the system, as has been the fate of many genera once sup- posed to be autonomous. There is great probability in favour of such a supposition, and it will perhaps be found that most species of Setrosiphon are similarly circumstanced. When we come to the consideration of fungi, we shall find how many genera must eventually be expunged. 72. The total absence of vascular tissue is one of the most general characteristics of Alge; but, as in Phenogams, the parenchymatous cells sometimes contain spiral threads, as, for instance, in the aérial roots of Orchids, or the little bulb- shaped processes which are are so common on the roots of Conifers; so also there are undoubted instances of spiral threads in Algae. In Zygnema, for instance, and its allied genera, we have repeated examples, sometimes exhibiting a * Zur Entwickelungsgeschichte des Collema bulbosum, Ach. von Julius Sachs. { Mr. Thwaites found discs of cells regularly pullulating from the stem of Lichina, and simulating distinct Alge. 94 INTRODUCTION TO CRYPTOGAMIC BOTANY. structure almost as neat as in vessels with compound spires ; though, sometimes, the principal part of the endochrome is simply collected into a single irregular band-like thread. The vascular tissue of plants in general, as observed before, is a mere modification of cellular tissue. All tissue, in fact, in an infant state, is cellular, and cell-walls, apparently simple, consist some- times, if not always, of spirally-arranged fibres. These are visible enough in many Phenogams. In Fungi we have the same structure, in Podaxon (Fig. 5, ¢), and Agardh has shown that the cell-walls of some Alga, as Conferva melagonium (as stated above, p. 8), have a spiral structure. The elder Agardh recognised the analogy between the woody fibres of plants and the threads of Conferva, and the analogy in point of structure is borne out as well as in more palpable attributes. We have already seen that the stems of the larger Alge exhibit a structure somewhat similar to that of Exogens, but the resemblance does not stop here: in such genera as Mesoglwa there is a distinct horizontai as well as vertical system; and what is very curious, in Batrachospermum and some species of Callithamnion (Fig. 26), the thickness of the stem is increased externally by a descending system from the branches. In such Alga, this is no merely theoretical notion, but one which a single glance at the microscope will confirm; and though the theory of Du Petit Thouars is now exploded as explanatory of the growth of Exogens, no one will deny that their growth is in direct pro- portion to the number of healthy buds which are developed. Kiitzing has figured dot-like canals (tiipfel of the Germans), in Laminaria digitata, and I have seen something of the same kind, though not so distinctly as in his figure, in a vertical section of Lessonia fuscescens. 73. In the simplest Algze there is no distinction of root, stem, or leaves. Some, in fact, consist of nothing more than cells, either entirely free, or floating in a common gelatine, and are multiplied by a constant division of the endochrome. Where, however, reproduction takes place by means of a spore, as in Isthmia, there is very generally something, however slight, of the nature of a stem, though the produce of this spore may, for many generations, be propagated only by division ; and, in INTRODUCTION TO CRYPTOGAMIC BOTANY. 95 such cases, the only semblance of a root is a little dilatation of the base, or occasionally a few divisions, consisting either of a single row of cells, or, where necessity requires, of a larger mass. In the higher Algz, as in the large species of Laminaria, the rootlike processes acquire a considerable size, the exposure to Branch of Callithamnion Hookeri, from Eng. Bot. t. 2938, compared with specimens from Mrs. Griffiths, and Mr. Ralfs. heavy swells and stormy seas necessitating a strong adhesion to resist the mechanical powers opposed to them. Where there is little danger of disunion the attachment is propor- tionally slight; and where, as in Sargasswm and Macrocystis, the individuals are destined to float as parts of large fields, sometimes miles in extent, on the surface of the waves, the plant often separates from its primary attachment altogether, and multiplication takes place by a constant re-division of the frond, as in the lower Algw. 74, The simplest Algz consist of mere cells; more complicated forms arise, first, from the articulation of such cells, end to end, by means of transverse partitions, and then, by the addi- tion of lateral cells by means at once of transverse and longi- tudinal dissepiments. According to the proportion in which these two processes are carried out, we have, on the one hand, 96 INTRODUCTION TO CRYPTOGAMIC BOTANY. such structures as Chordaria, representing simple or branched bodies like whipcord, or foliaceous expansions, often of con- siderable breadth, as the larger Ulvw. By a still further differ- entiation, we have, at once, bodies consisting of condensed and often elongated tissue, analogous to stems, and foliaceous ex- pansions resembling leaves. We cannot, however, regard these as of exactly the same nature as their analogues in Pheno- gams. If we compare the different species of Nitophyllum, we shall perceive that the midribs of the leaves are the same organs with the stems, and that the fronds themselves, how- ever they may simulate leaves, and answer the same end of exposing a greater surface to the surrounding medium to profit by its influences, have, by no means, the same organic value. The main end is rather one of nutrition than of aeration, though it is true that, in certain cases, even the leaves of Phenogams may, on occasion, answer both ends at once. But there, at any rate, analogy ceases; they are not, like the leaves of Phenogams, essentially symmetrical organs, on the due arrangement of which, after certain laws, the formation of the fruit-bearing organ depends; for there can he no pretence that the fruit of either kind is a transformation of any external organs, in the same sense in which it is under- stood in Pheenogams. 75. There is, however, in many species an additional resem- blance to true leaves, in the fact that, in certain conditions, they are deciduous, and re-appear the following year in new beauty, though not from buds, in consequence of nutriment stored up in the thicker and firmer part of the plant. Every one, for instance, who has observed these productions in their native spot, knows how vast a difference there is between the winter and summer state of Delesseria sanguinea; and though, perhaps, less generally observed, a series of the larger Lami- narice, in their progress from a little strap-shaped frond to the enormous whips with a hundred thongs, heavy enough to load a man, present a constant development of a new frond at the base of the old one. 76. It will be seen presently that these productions vary no less in colour than in form and structure ; and, within certain INTRODUCTION TO CRYPTOGAMIC BOTANY. 97 limits, such variations are indicative of, or at least accompany divisional characters. Some possess a beautiful herbaceous green, others exhibit the bright hues of flowers, and there are few tints which are not displayed by individual species. Next to green, however, the most prevailing tint is pink, passing into various shades of purple; or, on the other hand, olive, from a bright tawny or golden green to black. Even pure_blue occurs amongst the lower Alge. The colour of Algze does not require much intensity of light for its develop- ment. Many species of beautiful colours grow at depths where the light must be so small that no Phenogam could exhibit anything of its proper hue, supposing it possible for its blossoms to be developed under such conditions. 77. It has been long known that the green matter of Priestley, consisting of the lower Alge and their germs, acts on the atmosphere like the leaves of Phenogams. But, according to Aimé, as quoted in Payer’s Botanique Cryptogamique, p. 17, the colour of Algz is, in this respect, indifferent; and marine Alge in general absorb carbonic acid, and disengage oxygen, under the influence of the sun, exactly as Pheenogams. The quantity of oxygen disengaged by them is said to be im- mense. M. Aimé collected nearly two pints from a space of about two and a half square yards, by agitating the fronds. I believe, however, it will be found that some of the Oseil- latorie disengage noxious gases. Chara is certainly no Alga, and, therefore, I have no reason to speak of its pecu- liarities here. 78. Algze, in some of their varied forms, occur in all parts of the globe, reaching the utmost confines of vegetation, and, are, perhaps, capable of flourishing under greater extremes of temperature than any other organised bemgs.* Within certain depths which, however, descend in some cases to very numerous fathoms ¢ they abound in both fresh and salt water, * It is, however, Diatomacee only which extend so far. Animals abound towards the South Pole, far beyond the limits of most Algz, and Lichens ascend to greater heights. + Fucus vitifolius, for instance, was found by Humboldt, 192 feet below the surface. It could receive there only half the light of a candle, 7 98 INTRODUCTION TO CRYPTOGAMIC BOTANY. and occur whereever water trickles down constantly, or where the soil or rocks are moist, for where there is sufficient moisture, full exposure is by no means detrimental to their growth. If the doubtful genus Leptomitus, and its allies which grow on putrid or unhealthy animals, and the so-called Algee, developed in the intestines of Julus, be eliminated, there is scarcely one that can be considered truly parasitical ; or, with the exceptions before indicated, deriving any nutriment from the soil on which it is fixed. 79. As regards their distribution over the globe, like other Cryptogamic plants, their limits are extensive; nevertheless there are more marked features than might at first be supposed, from the constant motion and the continuity of the medium in which so great a portion of them grow. Many, however, flourish at depths where the warmth of tropical suns, apart from currents, is felt, and in similar temperatures of the sea, there is certainly a greater difference of species than in Fungi or Lichens. Under given atmospheric conditions, neither genera nor species of non-marine Alge vary much; at any rate, there is a very close resemblance between those on the Indian mountains, and under analogous conditions of climate, though with the intervention of thousands of miles. Amongst many of the lower Algx, such as Oscillatoria, Oalothria, &e., it is very difficult to speak of species, because the species themselves are often very loosely defined, and it is almost impossible to judge of such productions merely from dried specimens. It is a remarkable fact, however, that, abun- dant as the red-snow is in the European regions, it never once occurred in the whole of Dr. Hooker's extensive journeys amongst the loftiest mountains in the world, though there were Alge, Lichens, and Fungi enough, which could be identified with European specimens. The Desmidiacee of other countries than Europe and North America have been, at present, but little studied, nor does it appear that they are, in reality, numerous. Dr. Hooker’s Indian collections show but a trace of them. The Diatomacece, on the contrary, occur ata distance of one foot, whereas Lepidium sativum is scarcely greened by the light of two Argand lamps.— Pers. Narr., vol. 1, p. 88. INTRODUCTION TO CRYPTOGAMIC BOTANY. 99 throughout the world, and extend beyond the limits of any other vegetables. Their siliceous coats render the characters by which they are determined capable of perfect preservation, and though the species vary greatly, still, both as regards species and genera, different regions of the world produce altogether different forms, together with a certain quantity of cosmopolites ; and many now existent, are identical with, or at any rate, extremely similar to species occurring in strata anterior to comparatively recent alluvial deposits. Amongst the lower Chlorosperms, there are a few forms which are peculiar to particular districts, but, as research extends, the numbers of these will probably be greatly diminished. The curious Trypothallus anastomosans, Hook. f. and Harv., of the Antarctic regions, is identical with Kiitzing’s Palmodictyon viride, or, at any rate, belongs to the same genus. 80. As, however, we approach the larger and more important forms of the Alge of any of the three great groups, we find some marked examples of particular distribution.* The great feature of our own coasts is the extreme abundance of Lami- narice, not, indeed, of species, but of individuals; but as we get further north, especially on the western coast of America, and the opposite coast of Asia, they increase immensely in number and importance. On the contrary, the species of Sargassum require a higher temperature, and, in consequence, are unknown upon our coasts, except as wanderers. In the southern hemisphere, we have a host of most important Alge, belonging to the genera Lessonia, Durvillea, &., which are altogether unknown in northern regions. Caulerpa, again, is a genus but little known in European Floras, except in Spain and on the northern coast of the Mediterranean. It is represented, to a certain degree, by a few species of Codium, but our sands produce merely a few tufts of Vawcherta with- out a trace of Caulerpe, which are so remarkable in many warmer climates for the singularity of their mode of growth, * Tp all that relates to the distribution and classification of Alge, I must acknowledge my obligations to Prof. Harvey, especially in his work on North American Alge, published by the Smithsonian Insti- tution. 7* 100 INTRODUCTION TO CRYPTOGAMIC BOTANY. and sponge-like habit so different from that of most Alge. But species have their appointed tracts, even as genera. The common Fucus vesiculosus, for instance, which is so characteristic of our coasts at mid-tide, is not known in the Mediterranean except as drift, though it grows and even fruc- tifies there in floating masses, assuming, sometimes, peculiar forms. The distribution of species is, however, greatly modi- fied by the nature of the currents. Sub-tropical species, therefore, which occur only at the most southern extremities of England, occur on the side of Ireland exposed to the warm currents of the Atlantic as high as 53°; and to the same cause are due, most probably, the broad forms of Desma- rvestia in Loch Swilly, identical with those on the Spanish coast, though search might probably be made in vain at intermediate points. Seasons, too, have more influence than might be expected on the growth of Alga. Dr. Harvey has observed, for instance, that Padina Pavonia is much influenced by comparative warmth, though it has a wide geographical range; and such species as grow in shallow pools are more likely to be affected than deep sea species, for such isolated spots, in certain states of the tide, will, sometimes, attain a marked increase of temperature. Slight changes of temperature have, in fact, a greater in- fluence on Alge than on most other plants. In general, they are impatient of extremes or of exposure to strong light, as may be easily verified by any frequenter of our coasts. Some species are so delicate that a very short exposure is sufficient. Shallow pools, which are capable of being heated on the ebb of the tide, rarely afford Algs in good condition. 81. It might be expected that most of the seaweeds which are common on the western coast of Europe, would be more or less so on the opposite coast of America, and this is true to some extent ; but though Fucus vesiculosus and nodosus are characteristic forms of the American coast, Fucus serratus is entirely wanting, and other species, almost equally common with that in England, are either unknown or extremely rare. These species are, however, compensated by several kinds of INTRODUCTION TO CRYPTOGAMIC BOTANY. 101 Laminaria unknown to Europe. The truth, however, is that on a considerable extent of the coast, as far as Cape Cod, the species approximate more than our own to Arctic or sub-Arctic forms. Proceeding to the south the Northern Fuci cease, and are gradually replaced by Sargassum. The Callithamnia and Polysiphonie increase in beauty, Delesseria Lepriewrii, a New Zealand species, occurs, and the tropical Bostrychiw, one of which is found in company with the last-mentioned species, abound in the estuaries, till, in the Southern states, the forms cease to be those of Western Europe, combining the features of the Mediterranean Algee with those which are perfectly tropical. Species of Cawlerpa abound, and numerous allied genera belonging to Mediterranean or West Indian forms, remarkable for the large quantity of calcareous matter de- posited in their tissues. 82, A long list of fossil Alga is given by Endlicher, com- piled by Unger from the works of Sternberg, Brongniart, Lindley, and others. Such productions, where the determi- nation necessarily depends on outward form only, and not on intimate structure, are always more or less doubtful. The Algze most likely to be preserved in a fossil state are doubtless those calcareous species which resemble corals, None such, however, have at present occurred in any geo- logical formation. The genera enumerated by Unger, as far as they resemble in name those proposed for recent Alge by Algologists, will shew the supposed affinity of the fossil species, Confervites, Caulerpites, Codites, Encelites, Hali- servites, Zonarites, Laminarites, Sargassites, Cystosetrites, Halymenites, Sphorococcites, Chondrites, Rhodomelites, Delesserites.* 83. Amongst the organic remains contained in amber, none seem certainly referrible to this division, though Algoid forms appear, depending on the motion of bubbles of air in a resisting medium, or other physical causes. The tripoli of tertiary form- * An actual inspection of specimens arranged in museums, under these and other names, leaves an impression that there is not one of them which is rightly referred to Algw. Broken specimens of Oldhamia, an undoubted animal, resemble closely some Conferva. Perfect speci- mens, however, at once preclude such an affinity. 102 INTRODUCTION TO CRYPTOGAMIC BOTANY. ations, however, contains many undoubted Diatomacew, and some indications of these organisms appear in flint and opal,* as also of Desmidiacewe.t 84, The economical purposes to which Algz are applied are various ; but they are not now of so much importance as they were before modern improvements in chemistry taught a cheaper mode of obtaining carbonate of soda from common salt. The preparation of kelp, which gave employment to so many men, and which was a source of such large emolu- ment on many of our rocky coasts, is now almost obsolete, and there is no prospect of its being revived. A small quantity, however, is still prepared for the manufacture of iodine, which was first discovered in the lees of kelp, and is so important in medicine. The vegetable thiops is pre- pared by burning Fucus vesiculosus in a covered crucible. It is given in doses of from ten grains to two drams, and is said to be more efficacious than burnt sponge in scrofulous disorders. Its virtue is doubtless due to the small quantity of iodine it may contain, to which also is attributable the benefit of sea water in similar disorders. Calcified sea-weed is especially useful in the cure of fibrous polypus of the uterus, for which the Kreuznach waters have long been cele- brated, in consequence of their containing the same principle, (Med. Times, Aug. 18, 1855.) The principal use for which the large masses of seaweed which are thrown upon the coast are now employed, is in the preparation of manure, and it is to this that the fertility of many a district is due, as, for instance, the Isle of Thanet, which has for years sent to London the best English corn which appears in the market.{ A few species, such as Alaria esculenta, Rhodymenia palata, Iridwa edulis, &e., are regularly sold in the Scotch markets; and I can myself bear witness on more than one occasion, at so late a period as 1823, to being able to procure no other food amongst the Western Islands. Chondrus erispus and other Rhodosperms have long been sold by chemists for the preparation of a sort of blanc- * Ehrenberg in Poggendorff Annalen d. Phys., 1836. Ann. d. Se. Nat., Sér. 2, vol. 7, p. 27. (Zool.) + Turpin, |. ¢., p. 129. { Lewis, Hist. of Tenet,1 723, p. 13. INTRODUCTION TO CRYPTOGAMIC BOTANY. 103 mange; but they are now largely employed, even in the central parts of England, for feeding pigs, in the form of a jelly mixed up with meal and other ingredients. They contain a consider- able quantity of gummy and amylaceous matter, and, possibly, some albumen, to which they owe what medicinal property they possess, for they do not appear to contain iodine. Ac- cording to Schmidt, the jelly of carrageen is identical as to its chemical formula with starch and sugar, C’ H’? O'. Pereira considers it a distinct body from gum, starch, and pectin. Nearly the same substance exists in the Ceylon Moss, and, probably in many allied Algw, as in the Corsican Moss, Plocaria Helminthochorton, which contains besides a minute quantity of iodine, and has, perhaps, no active qualities. A more delicate jelly is prepared from Gracilaria lichenoides, spinosa, and Gigartina speciosa; the use of which is, however, confined, almost exclusively, to the East or Australia. It is a mistake to suppose that the Chinese swallows’ nests belong to the same category, since the sub- stance of which they are formed is secreted by the birds them- selves, Gracilaria tenax, together with some other species, however, affords another more important substance, viz., a glue, cement, or varnish, which is extensively used in China. Durvillea utilis is employed to thicken soup in Chili. One of the best edible preparations from Alge is the laver, which is, however, more used in the western than the eastern parts of England. Few condiments are more esteemed than this, where the taste has become habituated to its use ; but, like olives, it is seldom approved at first. It is, no doubt, a very wholesome food, but its use is not likely to become more widely diffused than it is at present. A species of Nostoc is largely consumed in China as an ingredient in soup; and an allied Alga has been found a welcome article of food in the Arctic regions. The cattle in Scotland and Norway browse upon the seaweeds at low water ; and the succulent branches and fronds of the Caulerpe are the favourite food of turtles. The whole tribe affords nutriment for hosts of mollusca and fishes, Several minor uses are made of Algz, such as the manu- facture of handles for tools from the thick stem of Lessonia fuscescens, and some other species, and of fishing lines from 104 INTRODUCTION TO CRYPTOGAMIC BOTANY. Chordaria filum. The siliceous cases of some of the Diato- mace are valuable test-objects for microscopes, and are used for polishing. 85. A few words on the mode of preserving Alge for the herbarium may not be amiss in a treatise like the present. Few objects are more beautiful when well preserved; but a great deal depends upon neatness of manipulation. The fresh water Algez, for the most part, do not make specimens beautiful to the eye, and the distinguishing characters of very many can only be retained by mounting small specimens in fluid, according to the method which will be described at the end of the volume. Useful specimens of many, however, may be preserved for the herbarium by floating them in water and slipping paper beneath them, or by simply drying with as little pressure as is needful to secure neatness and easy preservation in the herbarium. The gelatinous species will not, however, admit of much pressure, and it is often necessary to dry the specimens partially before they are at all compressed. The great difficulty to contend against in the larger olivaceous Alge is their chemical constitution, in consequence of which efflorescence is apt to take place, and dampness to ensue, which causes mould, and spoils the beauty of the specimens. It is perhaps impos- sible to avoid these inconveniences altogether ; but after the specimens have been washed with fresh water to remove any salt which may adhere to them, careful drying between well- dried paper, &¢., frequently changed, will, in a great measure, secure the desired end; the smaller specimens may be pre- served by floating them in water. As regards Florideous Algee, care must be taken that the specimens are not placed longer in fresh water than is absolutely necessary, as it is fatal to the beauty of many. A large portion may be preserved as before, by simply slipping paper under the specimens when floating, taking care that the branches lie in a natural position, and by no means artistically expanded ; and of the larger species, those which are gelatinous must be partially dried before they are submitted to pressure, while others will dry admirably if frequently changed, exactly after the manner of Phenogams. In no case should the pressure be extreme, so as to compress the stems unnaturally or to destroy their INTRODUCTION TO CRYPTOGAMIC BOTANY. 105 cellular structure. Many of these may be preserved in masses, provided they can be put by tolerably dry, and beautiful specimens may be prepared at home. The small quantity of salt which adheres to them is, in this case, rather beneficial than otherwise. The preparation of such beautiful samples as those which are distributed by M. Lenormand, requires a great deal of time and neat manipulation; in no case, however, must mere beauty be attained at the expense of utility, the great object in view being the preservation of specimens in such a state as to render every part capable of comparison with similar or allied species. Occasionally, it may be found that oiled paper, fine linen, or glass may be useful for the preparation of particular species, which are apt to cling to the paper which covers them; but any practised hand will soon invent such methods as peculiar properties of individual kinds may require. I do not recommend the use of linen too much, as I have seen many specimens, otherwise of con- siderable beauty, materially injured by it. The most delicate species may be readily transmitted by post if wrapped in fine muslin and enclosed in thin gutta percha or tin foil. After some days, specimens will be found in a good state of preservation, and as fit for microscopical investigation as when they were taken from their native rocks, provided the quantity enclosed be small. I have received hundreds of specimens from Mr. Ralfs and Myr, Thwaites in this way, which I have been able to study almost as well as if I had gathered them myself. The more delicate Algze soon decompose, even when kept immersed in salt water; and, in general, the sooner specimens are prepared after they have been brought home, the better, whether free in their gutta percha bag and tin vasculum, or immersed in little flasks of water; andif this be the case in our temperate realms, the necessity will be so much the greater in warmer countries. 86. Alge, like Cryptogams, taken as a whole, are evidently distributed into a few large groups, each of which consists of other subordinate divisions. If all such divisions are made of equal importance, or if the divisions are more numerous than are really indicated by nature, the effect will be to fritter away general views into mere details. 106 INTRODUCTION TO CRYPTOGAMIC BOTANY. 87. It is not the object of a work like the present to give a history of every systematic change, or of every step by which we have arrived at the present state of knowledge, nor do I feel bound to make room for more modern systems, which have departed from the unity and symmetry which were first sketched out by Agardh* the elder, and have been successively improved by his son, and by our countryman, Dr. Harvey. The modern French Algologists, as Montagne, Decaisne, &c., have also thrown much light upon the subject, but they seem to me to lay too much stress upon the zoospores, in their arrangements. No one appears to feel the real affinities of Algw better than Dr. Harvey, and there is surely no one one who has had such opportunities of examining them under every variety of climate and locality. The main divisions which he has proposed are three : 1. MELANOSPERMEZ (spores olive). 2, RHODOSPERMER (spores red). 3. OHLOROSPERMEZ (spores green). 88. That these divisions are as certainly founded in nature as those of Algals and Mycetals is beyond doubt ; but whether the names or the characters which those names indicate, are the best that might be chosen, or whether individual genera are rightly disposed, is another question. The difficulties are most glaring * According to Agardh’s Systema Algarum, published in 1824, the arrangement is, by analogy with the development of Phenogams: 1. Hyalinee (Diatomez, &c.) = Radix. 2. Virides (Confervee, &c.) = Herba. 3. Purpurez (Florides, &c.) == Flos. 4, Olivaceze (Fucoidee, &c.) = Fructus. According to this system the genera were arranged, but the whole was too fanciful to be permanent. I know of few things to be so much deprecated in science as these fancies. Arguments in favour of design in the work of creation, are only enfeebled by such puerilities, as by all other extravagance and exaggeration (compare above, p. 39). The first division was gradually merged in the second, and, with modifications as to the true affinities of species, the divisions are the same with Harvey’s. Lamouroux, in 1813, laid the foundation by the distinction of Fucacee and Floridee. Agardh was, however, in all probability but slightly acquainted with Lamouroux’s Memoirs, or if familiar with them, he did not pay them the attention they deserved. INTRODUCTION TO CRYPTOGAMIC BOTANY. 107 in the third division, which comprises a considerable number of species which have not green fruit in any stage of growth; or at least not as a primitive stage, for the red spores of the second order sometimes become green in decay. The contrary effect. takes place in some Chlorosperms, where the green assumes a deep red, but not rosy tinge, probably by the same process which changes the natural green of leaves into autumnal red. This is not, however, the point to which I allude; there is a considerable number still of species of Protococcus, Hamatococeus, &¢., which are essentially rose- coloured. But this is merely one of those cases in which the attributes of the superior order are indicated, as it were, by the first elements. The shades of transition from Hama- tococcus sanguineus, Bangia atropurpurea, and Porphyra (Fig. 27), the analogue of Nityphyllum, are certain, and it is only an unwillingness to adopt colour as a generic character which prevents such species from being dissociated. The cha- racters by which Botrytis is held distinct from Chroolepus, are scarcely stronger, at least technically speaking. Naturally they are as widely separated as the east from the west. In Batracho- spermvum, we see species possessing the true green of Chloro- sperms and the rosy purple of Rhodosperms; and the red species seem at first sight allied to Glaocladew, the green to Chorda- riacee; there is, however, no close definition even of species, though, to the eye, apparently so distinct, and the coloured indi- viduals are, probably, mere analogues, and no proper denizens of a higher order. In the tribe of Oscillatoric, there is frequently a deep purple, and sometimes even a rosy red. The waters of certain lakes, for instance, even at a distance, are red from the diffusion of Lyngbya prolifica, Grev. Again, in the Dia- tomacee there is seldom a grass-green colour, but rather a yellow olive (lederbraun, as it is called by the Germans), some- times approaching to a golden tint. Making allowance, then, for a few exceptions, which, from the very nature of vegetable productions, will occur in every systematic arrangement, the following characters may be proposed :— J, CHLOROSPERME. For the most part green, but varying occasionally to olive, 108 INTRODUCTION TO CRYPTOGAMIC BOTANY. purple, or other tints. Reproductive bodies, zoospores, pro- vided with various ciliary appendages, often resembling sper- matozoids ; or inactive cysts, filled with endochrome. Sper- matozoids rarely present. 2. RHODOSPERMES, Rose-red, or purple, rarely inclining to brown or green. Fruit—a, spores contained in particular conceptacles, either external or immersed : b, tetraspores, mostly immersed in the fronds, rarely contained in particular conceptacles, arising from a cell whose endochrome is quadripartite, and which ultimately separates into four distinct bodies. Amntheridia often on dis- tinct plants filled with active spermatozoids. 3. MELANOSPERMES. Olive green, inclining sometimes to brown, moncecious or dicecious. Spores, olive-coloured, either naked or contained in conceptacles, sometimes arising from the division of an endochrome into two, four, or eight. Antheridia often resem- bling the conceptacles, filled with active spermatozoids, Pro- pagation occasionally by zoospores resembling spermatozoids. 1. CHLOROSPERMEZ.—Spores green, often resembling sperma- tozoids; active or inactive. Moncecious. Spermatozoids, rare. 2, RHoDOSPERMEZ.—Spores red. Fruit twofold. Dicecious. Sper- matozoids general. 3. MELANOSPERMEX,—Spores olive. Dicecious or Monecious. Spermatozoids, general, or represented by similar zoospores. ALG. 89. It will be observed that there are two distinct modes of propagation amongst Algz, the one by zoospores, the other by inactive spores. This circumstance is proposed by Thuret and others as the foundation of a system. It seems, however, that by such an arrangement, plants of close affinities are widely sepa- rated. No one, for instance, can deny that the species included under the old genus Vaucheriu are closely allied; and yet,if this system is adopted, the species must be widely separated from each other. Caulerpa propagated by zoospores will then have nothing to do with Vuucheria propagated by inactive spores ; while Laminaviw will be separated from Fuci, with which INTRODUCTION TO CRYPTOGAMIC BOTANY. 109 they are so evidently connected. Besides, the zoospores occa- sionally arise from impregnation, as in dogoniwm and Bul- bochete. The same objections apply to the zoosporous and aplosporous divisions of Decaisne. 90. There is something attractive in the main divisions pro- posed by Kiitzing of Isocarpeee and Heterocarpew, but strictly speaking, the tetraspores of the rhodosperms are not fruit at all; they are only a sort of buds, and in consequence, the plants which bear them are more luxuriant than those which bear the true fruit. Neither is the fruit always of one kind only in the other division. Stilophora, for instance, with seve- ral other allied Algae, bears two distinct forms of fruit, each con- taining zoospores, both of which reproduce the species. Bangia, moreover, and Porphyra ought by no means to be in distinct main divisions, while the red-spored species of Hematococcus pass gradually into Bangia. Besides which, the seaweeds (Fucoidec) are scarcely more nearly allied to Conferva than they are to Chroolepus. If, however, such names as Chlorospermec and Rhodospermec were substituted, we should, with a few modifications, have undoubtedly two tenable groups, and the first of these, when divided into two, would make two equivalent with the first and third of Harvey. As regards the subordinate divisions, they are far too nu- merous, and separate plants closely allied to each other. I see no advantage, therefore, whatever in adopting Kiitzing’s rather than Harvey’s arrangement. The arrangement of Fries into Fucacee, Ulvacee, Diatomacee, is far inferior. It is universally admitted that the divisions of Decaisne are not tenable, but perhaps no one has contributed more than that excellent botanist, especially in conjunction with M. Thuret, to an accurate knowledge of these plants. It is scarcely neces- sary to notice that of Zanardini,* which has the disadvantage of joing Fucoidee and Floridee in one group, while it separates nearly allied species into another. Endlicher divides Alge into three orders: 1. Confervacew, 2. Phycordew, 3. Floridew, which are, as nearly as possible, synonymous with * Saggio di Class. delle Ficee, 4to, 1843. 110 INTRODUCTION TO CRYPTOGAMIC BOTANY. those of Harvey; and his names might be adopted, should those of Harvey displease. I do not, however, approve of Vaucheria being arranged with Phycoidec, or separated from Caulerpa, nor of several of the other details. It remains only to notice the system of Montagne in his article Phycoidées, in Orbigny’s dictionary. He divides Algze into three families : 1. Zoospermées, 2. Floridées, 3. Phycoidées ; which, with excep- tions as to details, are equivalent to Harvey’s three divisions. The Vaucheriw and Spongodic are, however, as truly zoo- spermic as any of the first division, and cannot, I think, be separated from it; and certainly Caulerpa ought not to be in a different main division from Vawcheria. 1, CHLOROSPERMEA.— Harv. (1841. 1852.) CHAoDINL= and ConFrerv#, Bory. 1823.—Hyatin# and Viripgs, Ag. 1824.—Utvace# and Diatomacn, Fr, Fl. Scan.1835.—ZoospERMEA, J. Ag. 1842, Mont. 1847.—Zoosporn& and Synspores, Decaisne, 1842. —TZoosPorE®, Thuret, 1851.—Conrervacea, Hndl. 1843,—Isocarrnm (Gymnospermeze), in part, Kitz. 1847 —GontpiopHycum, Zanardini, 1847.—Diatomacre® and ConFrervacres, Lindt. 1853.* For the most part herbaceous-green, but varying occasionally to olive, purple, and other tints. Extremely various in form and appearance, often filiform, propagated by the simple divi- sion of the endochrome, by the transformation of particular joints, or by the metamorphosis of the endochrome into zoo- spores. Sexes rarely distinct. 91. When a piece of stone is exposed to the air, and shaded from the sun, or a stream of water flows down a rock, or a bed of snow is long subjected to radiation, greenish or olivaceous and sometimes reddish matter is formed, consisting of variously organised bodies, which belong to this primary group of Alge. Together with Lichens, they are the first heralds of vegetation ; * None of these are the precise synonyms of Chlorospermec, because all the authors understand the affinities of certain groups and species differently. INTRODUCTION TO CRYPTOGAMIC BOTANY. 11] their decay forms a nidus for the growth of minute mosses ; soil gradually accumulates from their decomposition, and that of minute Phenogams which succeed them, till the whole surface is covered; the rock itself, if like granite, composed of parts readily subject to deintegration, is by degrees coarsely pul- verised, soil is formed, and the surface is ready to supply the wants of man, and the various members of the animal world which administer to his needs, or concur in the pre- servation of the balance of the organised world, and of the elements by which it is supported. Unimportant, then, as these minute beings may be at first sight, for many of them are quite microscopic, even the more obscure perform an impor- tant part in the economy of creation. Physiologically they are of much interest, because they represent the component Fig 27. a. Hematococcus sanguineus, Ag., from an authentic specimen. b, Bangia atropurpurea, Lyngb. e. Porphyra Boryana, Mont., from an authentic specimen. All more or less magnified. parts of which the larger species are formed. It is impossible, for instance, to trace the connexion between Navicula and Schizonema, Gleocapsa and Seirosiphon, or by a threefold bond between Hematococcus, Bangia and Porphyra, without acknowledging that this is the case, though we may not proceed so far as Agardh in his notions, which extend to the point of considering even Phenogams as made up of Cryptogams. The Cryptogams may indeed be representatives or analogues of their organs, and the study of the one may be illustrated by the other; but we cannot go further consistently with sound philosophy, and perhaps it may not have been the intention of Agardh, after all, however strong his language may be, to 112 INTRODUCTION TO CRYPTOGAMIC BOTANY. convey any profounder notion. In fact the differently coloured species which are referred to one genus on account of perfect similarity of structure, may not, as observed before, in reality'all belong to the same category; but as we are restricted in natural history to certain definitions, and bodies which agree with one another, as far as those definitions, go, must needs be asso- ciated, we must be content to leave the matter as it is, till a profounder knowledge of the objects of creation may enable us to unravel the order which has been observed in their crea- tion, and the natural relations by which small and great form one harmonious whole. 92. Chlorosperms are divisible into several distinct and well-marked groups, which are again divisible in accordance with nature. The object of the present treatise, however, is not go much the description of each individual form, as such an indi- cation of the more prominent features as may either give some general knowledge of the structure of Cryptogams, or render comparison with higher types simple, and at the same time certain. I shall therefore confine myself to the larger divisions, referring those who wish for more specific information to par- ticular treatises, for which some facility will, I trust, be given by the subjoined lists of the more prominent works and memoirs in each subject. 93. Now there are at least twelve salient groups which cannot fail to attract the attention of every student, of which that which contains the simplest forms shall come first. The others cannot follow exactly in the order of their affinities, as no ‘linear arrangement can possibly be consonant with nature. The groups will be the following. 1. Palmellew. 2. Desinidiacee. 3. Diatomacee. 4. Con- fervacee. 5. Batrachospermee. 6. Hydrodictyw. 7. Nos- tochine. 8. Oscillatorie. 9. Conjugate. 10. Bulbochetec. 11. Siphonew. 12. Ulvacew. These again form three dis- tinct groups, the first consisting of those species in which the individual cells, rarely forming compound threads or expansions, are the prominent features; the second of those which are essentially filamentous; and the third of species essentially foliaceous. CHLOROSPERMES. Foliaceous Cellular (Diatoma), Filamentous (Conferva). (Ulva). INTRODUCTION TO CRYPTOGAMIC BOTANY. 113. Articulate. Inarticulate. Ulvacee. mation of two new cen- tral half cells. Zoospores, minute. Zoospores, large. Siphonee. Cells dividing by a simple dissepiment. \ Palmellee. Cells dividing by the for- Desmidiacee.—Green. Cells free from silex, Diatomacee.—Y ellow-brown. Cells siliceous. Confervacee.—Without any com- pound axis. Articu- lations mostly longer than their diameter. Batrachospermee.—Threads partly incorporated into a solid axis. Hydrodictye —Reticulated. Nostochinee—Threads very slen- der, moniliform, in- vested with mucus, or surrounded by a gelatinous mass. Oscillatorie—Cells very narrow, Threads free, fascicu- lated, or compacted, simple or branched by apposition. Conjugate.—Zoospores from the union of two endo- chromes, in the same or contiguous threads, or from division of a single primary endo- chrome. Bulbochetece —Zoospores from divi- sion of a secondary impregnated endo- chrome, J14 INTRODUCTION TO CRYPLOGAMIC BOTANY. 1. PatmeLLen. Dye. Kiitz. Mont. Harv. (Protococeoidee Endl.) Cells free, or surrounded by a gelatinous mass, some- times stipitate, propagated by the division of the endochrome, which is mostly quaternary, and sometimes transformed into ZOOspores. 94. The essential foundation of every vegetable is acell: the very simplest mode therefore of vegetable life which can be conceived, is that of a mass of free cells increased either by partition of the endochrome, or by pullulation from the sides, as in the yeast plant. The two modes, however, seem to indi- cate two separate types, which may diverge from a common point so as to produce distinct series, while in other cases both modes of increase may be united in the same indivi- dual. No true Palmelloid will increase its cells by pullu- lation, and therefore in the very outset such productions as the yeast plant will be looked upon with suspicion—suspicion which is more than confirmed by an intimate study of its dif- ferent stages of development. There are, moreover, other pro- ductions, as Palmella prodigiosa, which, from their peculiar habit, seem rather. to indicate affinity with fungi. The rapi- dity with which Palmella prodigiosa spreads over meat, boiled vegetables, or even decaying Agarics, is quite astonishing, making them appear as if spotted with arterial blood; and what increases the illusion is, that there are little detached specks, exactly as if they had been squirted in jets from a smal] artery. The particles of which the substance is composed, have an active molecular motion, but the morphosis of the production has not yet been properly observed, and till that is the case it will be impossible to assign its place rightly in the vegetable world.* Its resemblance to the gelatinous specks which occur on mouldy paste, or raw meat in an incipient state of decomposition, satisfy me that it is not properly an Alga. Neglecting these, we have still a multitude of species, varying greatly in colour, and some- times assuming tints of red, blue, and yellow, with an admix- ture of olive, produced, too, in situations where Alge and not Fungi are to be expected, which, from their simple struc- * See Stephens in Ann. of Nat. Hist., p. 409; and Berk. in Gard. Chron., 1853, p. 15. INTRODUCTION TO CRYPTOGAMIC BOTANY. 115 ture and- mode of propagation, are united under one common name of Protococcus. One of the most familiar examples is the P. cruentus, which is to be found at the northern base of almost every wall, provided it be sufficiently damp, looking as if venous blood or the sediment of port wine had been poured upon the ground or stones. Such productions may sometimes be the infant state of more complicated organisms, but there is no reason to believe that such is the case in the present instance, nor in several other similarly constituted species. They are more or less gelatinous, in proportion as a greater or less quantity of mucous matter is secreted from the surface of the spores, or from the greater or less degree of solubility of this matter; but the gelatinous substance is by no means to be considered as primary, or approaching in any respect to what the Germans call wrschleim, a primitive jelly, which they conceive to arise from chemical combinations, and so in process of time to give rise by spontaneous generation to reproductive globules. In some cases, it is not possible to see the mode of propagation very clearly, in consequence of the diminutive size, but wherever it is visible it seems always to arise from division of the endochrome. At any rate, in the red snow, Protococcus nivalis, we havea distinct and repeated division of the endochrome into four, and attended by such curious phenomena, as to have made it a question whether it belongs to the vegetable kingdom at all.* The red snow has long been the wonder of our Arctic voyagers, and travellers among the Alps, but its curious characters do not admit of examination from dried specimens merely, Fortunately a similar, if not the very same production (Fig. 8,9), grows abundantly in many ex- posed situations, and living specimens have afforded Cohn and others opportunity of study. In the very confines of the order, we thus become acquainted with the striking resemblance which is exhibited by certain states of Algze and Infusoria: resem- blances which are so close as to be perfectly convincing that we must greatly modify our notions of the distinctness of * Shuttleworth sur la matiére colorante de la neige rouge, Bibl. Univ. de Genéve, Feb. 1840. 8 * 116 INTRODUCTION TO CRYPTOGAMIC BOTANY. animal and vegetable life, if we wish them to agree with fact, and not with mere arbitrary theories. 95. If the genus Protococcus is to be confined to simple forms, it is clear that several of the so-called species referred to it by Kiitzing, must be erased ; it is, however, certain that some of the substances in question are mere elements of other pro- ductions, and that, inasmuch as the species must either be propagated by the individualising of the granules contained in their protoplasm, or by the division of the protoplasm by dis- sepiments, we must either have two series of forms, or two modes of propagation must be common to the genus, if not to every individual in it.* The phenomena exhibited by P. pluvialis are rather in favour of the former view ; and if so, 1t will be impossible to distinguish some of the larger Pro- tococet from such genera as Glwocapsa, the characters of which depend upon the higher development of the spores, and the numerous coats of which the cellular walls consist. The fact is, however, that the limits of the numerous genera proposed by authors, and more especially by Kiitzing, are by no means fixed. Indeed, Kiitzing himself looks upon many of his species as mere forms, but if every form is to have a name, there will be no limit to spurious species, and no chance of ever arriving at a natural arrangement; for it is clear that, if in nature there is really a distinct plan, every intrusive species must tend to derange it, or to render the plan itself obscure. Kiitzing indeed points out, in his work on German Alga, different species of Scytonema, of which he believes certain kinds of Gleocapsu to be forms. This and many other similar points were long since detailed to me, by Mr. Thwaites, in the course of an almost daily correspondence ; but unfortunately he was unable to publish the full result of his observations * It is probable, that wherever propagation takes place by the mere division of the endochrome without any transformation, we have either early stages of other Algz and Cryptogams, or mere propagation by ger- mination. In some species, Zoospores are produced, in others, spores by copulation, and similar appearances may hereafter be discovered in all, Some Desmidiacee and Diatomacee may grow for years without forming a spore, the propagation being carried on meanwhile by mere division. INTRODUCTION TO CRYPTOGAMIC BOTANY. 117 before he went to Ceylon, and the duties of his station require so much active labour, that he has been obliged to confine his thoughts and care principally to them, to the neglect of his former studies, a circumstance of much regret to all lovers of Crytogamic Botany. Some Gleocapse, undoubtedly, are states of more highly organised forms, as Ephebe, which clearly does not belong to Alge at all, but to the gelatinous Lichens. It is probable, however, after all, that there may be real species of these lower genera; species, that is, which do not undergo any further transformation ; for mere similarity of form or structure does not always point out similarity of essence, or we could not distinguish the cellular state of some animal organisms from their analogous forms amongst vege- tables. Whatever be their nature, few objects are more beautiful under the microscope, than some of the higher and more perfect forms, and few give a better opportunity of stu- dying the development of cells, whether as regards their division or the nature of the walls. One of the most curious forms, perhaps, is that assumed by some species of Gleocapsa, in which the inner membrane repeatedly bursts through the outer, though always adherent behind, so as to form a gelati- nous mass of annulated threads, with a bright eye at the tip of each.* The endochrome is occasionally bipartite, and then each new endochrome acts for itself The species which I Fig. 28. Gleocapsa Hookert, Bork. & Hass. Threads and spores highly magnified, from specimens communicated by Sir W. J. Hooker. * Dr. Gieswald has figured a similar appearance in the mother-cells of the pollen of Cucurbita, Linn. xxv., tab. 1, fig. 30. 118 INTRODUCTION TO CRYPTOGAMIC BOTANY. have chosen for illustration, is one detected on the chalk cliffs of Norfolk, by Sir W. J. Hooker, and, perhaps, the group is incapable of any higher development. Other forms depend upon the comparative compactness of the gelatinous mass in which the reproductive bodies are contained, and on the cellular structure assumed by some, as in Botrydina, from the close pressure of the several component cysts. 96. The next group is that of Palmella. Ifthe figures of Kiitzing,* relative to this group, be examined, there will be seen in many, an evident trace of slender, supporting threads. Mr. Thwaites,+ however, seems to have been the first who properly described this structure, and it is probable Fig. 29. Palmelia botryoides, Greville. A portion of the threads which radiate from a large central cell, forked at their tips, and supporting on them elliptic cells, surrounded with gelatine, highly magnified. From a specimen communicated by Mr. Thwaites. Compare Nageli Gattungen Einzelliger Algen, tab. 2. E. that it belongs to the greater part of the species,t and that some which do not really possess it, would be better associated with the group first mentioned (95). There seems in these to be rarely any such multifold division of the endochrome, or adhe- rence after division, as often prevails there. The spores them- * Tab. Phycologice, tab. 19, iv. 21; v. 25; i. and v. 26; i, and ii. t+ Ann. of Nat. Hist., vol. xi. p. 312. + A figure of a new species of Coccochloris, C. Brebissonii, Thw., is given in Ann. of Nat. Hist., March and April, 1849. This possesses the same filamentous supporters as P. botryoides. The structure of the frond of Synadissa and Paulia, two gelatinous Lichens, exactly accords with that of Coccochloris, INTRODUCTION TO CRYPTOGAMIC BOTANY. 119 selves, too, are for the most part oblong, and point already to some of the lower Desmidiacew. In Palmoglea Mene- ghinii, at least, there is a distinct coupling of neighbouring spores; and Brébisson has noticed a similar fact in Coccochloris protuberans and rubescens, while the transparent peduncles point in the direction of certain Diatomacew. The limits of this group are uncertain, from the true nature of all the spe- cies being at present imperfectly known, and, consequently, some of the more compact forms, such as Entophysalis, Hy- drococcus, and Palmophyllwm, may, for the present, oscillate between this group and the last. In such plants as Palmellu botryoides, Mr. Thwaites does not consider the bodies figured at the tips of the threads as spores, but as more properly buds, since true fruit is formed in some, by conjugation, and in others, by the conversion of the endochrome into zoospores. The suggestion is one of considerable value, and has an im- portant bearing on those Algae, which, like Glwocapsa and Nostoc, seem multiplied solely by division of the endochrome. It should be observed that these bodies, after a time, put on a form precisely like that represented in Glewocapsa Hookevi (Fig. 28). The curious genus, Lntospeira, leads through Spi- rotenia to Zygnema. Palmodyctyon, Kiitzing, which is pre- cisely the same thing with 7’rypothallus, Hook. and Harv., is evidently a member of the Protococcoid group. According as the endochrome divides, vertically or transversely, the mass increases in width or length; and as this division alternates after some tolerably fixed law, a network of greater or less width is formed, according to the proportion of vertical to horizontal division. 2. Desmipiace&. Ralfs. Cells void of silex, free, or forming brittle threads or minute fronds, increased by the formation of two new half cells in the centre, so that the two new cells consist each of a new and old half cell. Spores generated by the conjugation of two distinct individuals. 97. The genus Entospeira leads directly to Sprrotenia, a member of one of the most beautiful, varied, and singular group of Algze, which has been admirably illustrated by Mr. 120 INTRODUCTION TO CRYPTOGAMIC BOTANY. Ralfs.* All agree in their increase by the partition of the mother cell, accompanied by the growth of two new half cells (Fig. 30, a. b.). In many cases, the division goes no further, but each half, with its new lobe grows into a perfect whole, and Qo @, “aangonn> “gga TUONO 8888p Fig. 30. a. Micrasterias denticulata, Bréb. b. Scenedesmus quadricaudatus, Turp., after Mr. Ralfs, both shewing the origin of the new half cells. ce. Threads of Wostoe verrucosum, after Thuret. All more or less magnified. b Fig. 31. Fig. 32. Fig. 33. Penium Jenner, Closteritum acutum, a. Euastrum ele- Ralfs, with its spore Bréb. free and in gans, Kiitz. magnified. From conjugation, magni- b. Spore of the Mr. Ralfs. fied. From Mr. same, magnified. Ralfs. From Mr. Ralfs. * Ralfs’ British Desmidiacem, 8vo. 1848. INTRODUCTION TO CRYPTOGAMIC BOTANY. 121 again divides. But this is by no means the case with all, for the two original halves do not always separate, but remain united with their progeny for many generations, thus forming a fili- form body (Fig 7, a), in which the two primary halves are at either extremity, and the youngest in the middle of the thread: a mode of increase which we shall meet with again in the fol- lowing tribe. Nor is the connection always confined to deve- lopment in a straight line. In those species which divide obliquely, an orbicular frond is sometimes formed, as in Pedi- astrum, though seldom one of any remarkable size. The fronds, if they may be so called, or cells, differ in almost every conceivable way, from a right-lined parallelogram or curved bow, to a deeply pinnate or strongly serrated thread. They are, for the most part, strongly constricted, so as to appear like two dis- tinct cells; but this is by no means universal, for in Closterium there is no greater constriction than in many species of Con- ferva. They are either smooth, finely granulated, verrucose, or beset with forked spines, insomuch that nothing can well be more curious than the varied outlines which they present under the microscope. Besides the spines, in the genus Xan- thidiwm, there is, in the centre of each half-cell, on either side, a curious tubercle, the edge of which is sometimes granu- lated, but whether it has any especial function or not, is un- known. Mr. Ralfs doubts whether the increase of the fronds, by separation, can be called propagation, but if it be considered in the following way, it will be clear, I think, that it is properly a propagation, though not a fructification. Supposing the two original lobes to be called A, the second B, the third C, and so on, the mother frond will be represented by AA, the second by AB BA, the third by AC CB BC CA, of which CB BC have no part of the original frond, and may, therefore, be considered as entirely new individuals. Another mode of increase is from the swarming of the grains of the endochrome, which become individualised as in other Algee, and so give rise to a new gen- eration. These bodies are figured with filiform appendages by Braun* in Pediastrum granulatum. But, besides these modes of propagation, there is another, respecting which we shall have * Algarum unicellularium genera nova et minus cognita, tab. 2 B. 122 INTRODUCTION TO CRYPTOGAMIC BOTANY. more to say under another group, which consists in the union of the endochromes of two contiguous vesicles, in consequence of which, a single large spore is formed in the connecting tube. These spores are mostly globular, but like the fronds themselves, exhibit great differences of surface, so that, apart from the matrix, they may be taken for the sporidia of truffles, or other heterogenous bodies. In many cases, they have no resemblance whatever to the parent frond, and though mixed with them, would never be suspected to have a common origin, until the union of two vesicles, and the consequent spore, should be ob- served. These, however, when once formed, are propagated by division, exactly after the fashion of the ordinary cells, and in the third generation acquire their normal form, which they may continue to propagate for years, without ever forming a true spore. They differ most materially from the following tribe, in the constant absence of a siliceous coat,* and though it has been attempted to shew that it does exist in the fossil species, more accurate observations have detected deflection of the spines, without fracture, which is inconsistent with such a notion. In one particular group (Closterium), distinguished for the more or less entire outline, which is either straight or arcu- ate in most of the species, there is a peculiar organ at either ex- tremity, consisting of a hyaline or straw-coloured cell, containing a multitude of active molecules, possibly of sexual import. Many of the species of Clostertum are remarkable for the close-set longitudinal strie with which the cells are marked. Traces of striee have, however, been found in a T'yndavridea, by Mr. Jenner, and in Tiresias, by Mr. Bowerbank. Desmidiacee are confined almost exclusively to fresh water, though Mr. Thwaites has found one or two species in brackish water, but in every case such species only as also occur in fresh water. Little can be said about their distribution, for few extra-European species are known; and as we travel to the South of Europe, the species appear to diminish in number, their central point, perhaps, being the South of England. There was a trace merely of some Clos- teriwm in the Himalayan collections of Dr. Hooker and Dr. * Tt is conjectured, however, that a small portion of silicate of iron does exist in some species of Closteria, communicating a ferruginous tinge. INTRODUCTION TO CRYPTOGAMIC BOTANY. 123 Thomson. In the United States, a few species occur, and are described by Bailey, and probably the number of these will be much augmented. Arthrodesmus tania, Ehrb., is recorded amongst others, They occur principally where there is some ad- mixture of peat,andin clear pools rather than in running streams, and never where the water is muddy. In limestone countries, where the soil is merely alluvial, they are comparatively rare. This is, however, true, only of the more noble species. Such genera as Scenedesnvus are, perhaps, more common in limestone districts, than elsewhere, and scarcely a glass of water can be set aside, exposed to the influence of light, which does not produce a host of forms or species. A few species are preserved in a fossil state, in flints and other transparent minerals. It is diffi- cult, at least in comparing recent and fossil specimens, to deny their identity, so precisely similar are they in form. They are, however, principally spores, and not, as Ehrenberg supposes, perfect forms of Xanthidiwm. Several species are described by Mr. H. H. White, in the Microscopic Journal, vol. ti. p. 35. Baily has detected cells of various species of Closteriwm and Euastrum, in fossil marls of New Hampshire and New York, and in the marl of Scotchtown, N. Y., below the Mastodon giganteus. Spores have been found by Mantell in the grey chalk of Folkestone, 98. Much controversy has existed with respect to their true nature ; but at the present day, few advocates will rank on the side of Ehrenberg ; for if in some points there be anomalies, as in Closteriwm, their whole history is so evidently vegetable, their mode of increase, growth, &c., that if we refuse them the title of vegetables, we may as well dispute that of the whole tribe of zoosporous Alge. As for their producing occasionally bodies, endowed with active motion, it is now a matter of cer- tainty, that such bodies exist in a variety of Algz of very different construction ; and it is by no means a fact without exception, that membranes, unless cleansed from every extra- neous matter, will not exhibit the reaction peculiar to cellulose, on the application of the proper chemical tests. But, perhaps, the most important point of all, is the fact that, under the in- fluence of light, they give out oxygen, which, added to other 124 INTRODUCTION TO CRYPTOGAMIC BOTANY. matters, is quite convincing. Some of Ehrenberg’s arguments we do not think of sufficient importance to bring forward here. As regards practical use, none at present is known; though doubtless the species exercise their proper part in the general economy of the world, helping to purify the water, and to afford food to mollusca and other animals. In some species of Closteriwm, a distinct circulation has been observed. 3. Diatomaces&, Ag. (Naviculacea, Ehrb.)* Propagation and division of cells asin Desmidiacee. Walls of cells containing a large quantity of silex, often beautifully sculptured. Endochrome golden brown. 99. These curious productions are often united with the fore- going into asingle group, but they seem so clearly distinguished by the flinty shell, which is almost always curiously striated, and the absence of pure green colouring matter, that they seem to me to form a group of at least as much importance as the others adopted in this place. As in Desmidiacee, there are solitary species, and others grouped into lines or membranes ; and in the few which have been observed to produce new plants by means of spores, the new productions do not exhibit at first the normal character of the species. The division of the fronds or cells, where it can be observed, takes place precisely in the same way as in Desmidiacece, and no genus perhaps exhibits this more distinctly than Isthmia (Fig. 7, b). The genera are more numerous than amongst the Desmidiaceaw, and are fre- quently most acutely characterised ; and not only from their peculiar striation, or singular form, but perhaps also from the perfection in which dried specimens exhibit the minutest cha- racters, they are favourite microscopical objects. Both in the solitary and associated species there is frequently a distinct pellucid peduncle, which in those which have a flabelliform frond is dilated above, and in some cases forked, or repeatedly dicho- tomous. In such cases every new frustule remains attached, the base dilating as need requires ; but in the filiform species, the attachment is confined to a single corner, and probably the * The work of Mr, Smith on Diatomacee may be quoted here with the same praise as that of Mr, Ralfs on Desmidiacee. Like that, it is perfectly origina], and an important contribution to science. INTRODUCTION TO CRYPTOGAMIC BOTANY. 125 stem is never developed, except where the plant has sprung from a spore. The siliceous coats of the cells are not only variously marked, but beneath these and the lining membrane there are often little channels) Along the line of suture in disciform or circular frustules, but more generally at the extremity of the valves only, when oblong, linear, or elongated, there exist perforations in the silex, which permit the sur- rounding water to have access to the surface of the internal cell membrane. Without some such provision, it is almost impossible that there should be any interchange between the contents of the cells and the surrounding fluid. Diatomacee were long Fig. 34. Epithemia gibba, Kiitz. From Mr. Thwaites, in Ann, of Nat. Hist., vol 20, tab. 22.* The two original individuals have each split up into two frustules. believed to be animals, and this view has more especially been maintained by Ehrenberg ; but the discovery of the coupling of fronds by Mr. Thwaites, and the confirmation of the fact by * [have two or three mounted specimens of different species, and from amongst them, Z. gibba, from Mr. Thwaites, of Diatomacee in con- jugation, confirmatory in every respect of his observations. 126 INTRODUCTION TO CRYPTOGAMIC BOTANY. myself, Mr. Broome and others, leaves no doubt that they belong to the same order of beings as Desnuidiacee and Conju- gate. The process of conjugation as described by Mr. Thwaites in Kunotia turgida, takes place in the following way. The two frustules being brought near to each other by their concave surfaces, two little swellings arise in each, meeting two similar ones in the opposite frustule. These soon unite and elongate ; the dissepiment is absorbed, and the endochromes of the two frustules mix. A spore is then formed in each of the two connecting tubes, which increases in size til] it resembles in every respect the parent, except in its much larger size. In the same group, therefore, frustules of very different sizes may occur, especially as the new frustule will divide several times before it acquires the normal dimensions of the species. In some species, as in those which form threads, the new indivi- duals do not resemble the old, but put on very different forms, as in the Desmidiacec, and have in consequence been referred by authors to different genera. A large quantity of mucus is often generated during the process, in consequence of which, as in our figure, the old and new frustules are bound together in a common group. This jelly is of consequence in deter- mining the difference between old and new frustules in those genera in which they do not differ materially from each other. In Fragiluria, only a single spore is formed. In every case, the two parent frustules are split in half by the swelling of the spore. In some cases the new spores acquire a stem, even where the frustules are not normally stipitate. At present, as far as I know, active granules have not been discovered in the cells; and it appears that true spores are far less common here than among the group just described. The species are far more widely diffused, and extend beyond the limits of all other vegetation, nor is there probably a portion of the world where there is sufficient water to allow of their production, from which they are entirely excluded. They flourish both in standing and running water, but they are found, also, on the bare surface of the ground, or on objects, as ralbits-dung, lying upon it ; and in South America they occur amongst lichens, upon the trunks of trees. While, on the one INTRODUCTION TO CRYPTOGAMIC BOTANY. 127 hand, they do not altogether avoid thermal springs, they abound amongst the pancake ice of the South Pole, as far south as seventy-eight degrees, where they must occasionally be subject to very low temperature. “Though much too small to be discernible to the naked eye, they occur in such countless myriads, as to stain the berg and pack ice, wherever they are washed by the swell of the sea; and when inclosed in the con- gealing surface of the water, they impart to the brash and pancake ice, a pale ochreous colour.” As the siliceous coats are indestructible under ordinary circumstances, even when these productions have been swallowed by animals, they are readily distinguished, either on examination of the contents of the stomach or of voided excrement. Consequently, where- ever these substances are deposited, they are to be found, as in the penguin rookeries, and other sources of guano, where they remain for ages, having been in the first instance swallowed with the mollusca, of which the food of the birds mainly consists. The shells of the dead animals also gradually subside, and in conse- quence, myriads are in some situations brought up with sound- ings. It can be no matter of surprise, therefore, that these bodies, though so minute, are perfectly preserved in a fossil state in several strata, in some instances in such abundance, that they are collected and sold under the name of Tripoli polishing powder, for which purpose they are admirably adapted. Dr. Ehrenberg even asserts, that species are to be found in a living state in situations where they have been propagated from times far anterior to the present modification of the earth, to which man has been assigned as an occupant; but such fancies require the very strongest proof before they can be received as certain verities. Some notion of the extent to which they are depo- sited in modern days may be conceived from the facts adduced by Dr. Hooker. “The Phonolite stones of the Rhine and the Tripoli stone, contain species identical with what are now contributing to form a sedimentary deposit (and perhaps at some future period a bed of rock), extending in one continuous stratum for four hundred measured miles. I allude to the shores of the Victoria barrier, along whose coasts the soundings examined were invariably charged with Diatomaceous remains, 128 INTRODUCTION TO CRYPTOGAMIC BOTANY. constituting a bank which stretches two hundred miles north from the base of the Victoria barrier, while the average depth of water above it is three hundred fathoms, or one thousand eight hundred feet.”* 100. But not only are species found in a fossil state which are identical with recent forms, but the trade winds bring over large quantities in what Ehrenberg calls Passatstaub, or trade wind-dust, which, sinking through the upper current, streaming from America, into the lower stratum, falls in the form of fine powder. This, however, does not contain for the most part African forms, though apparently coming from that coast, but truly American species, many of which are identical with those from the Antarctic. Another curious fact is, that they are thrown up with volcanic ashes from active craters; but the same power which in certain instances would carry the fish from the sea, would be sufficient to waft such far less perishable bodies, in a state capable of recognition. It would take many pages to go through the different lists of species peculiar to the different parts of the globe; many forms, how- ever, which do not occur at present in our own country, are abundant in certain fossil deposits, and in exotic lands, but by no means to the exclusion of Mediterranean forms from the cold southern latitudes. In the collection made by Dr. Hooker in the Himalayas, whether in hot springs, or in the mountain frosts and streams, the species resemble closely our own; and probably, when theyshall have been sufficiently examined, few new species, and certainly no novel forms, will be detected. A few instances will shew in what distant localities the species are found. E’pithe- mia gibba, a very common British species, occurs also in Italy and Ceylon; Epithemia Westermannt at Warehamand Ceylon; Actinocyclus undulatus, Kiitz., in various places in England, also in Peruvian guano, and in Virginia; Triceratum alternans, Bail., at Poole and Folkestone, and also in Peruvian guano. 101. It is quite impossible to notice every form, we must therefore content ourselves with passing in review merely such as may be most characteristic. There are three principal groups, * There is a bed of Diatomacee, at Richmond, in Virginia, on which the town is built, eighteen feet thick. INTRODUCTION TO CRYPTOGAMIC BOTANY. 129 the first of which contains those with smooth or transversely striate frustules, but neither vittate nor areolate, the second with vittate and the third with areolate frustules. The first compre- hends far the larger number of species and the least interesting forms. Some are perfectly free, as Vavicula, others attached by one surface, as Cocconeis; some form long threads, the frustules of which adhere tolerably firmly at their commissures, as F'ra- gillaria, or separate alternately, being suspended at a single point so as to form curious chains, as Diatoma; a few, in conse- quence of assuming a circular disposition, are cuneate, as Merv- dion ; others approximate some species of Conferve, forming straight lines with more or less cylindrical frustules, as Melo- seira ; some, again, have singularly curved discs, as Swrirella campylodiscus ; one group has strongly developed, and some- times branched stems, as Gomphonema ; one curious set is always surrounded by copious mucilage, so as to form distinct, and often branched fronds, as Schizonema; while Dickiea takes the habit of an Ulva. They are produced both in fresh and salt water, and even those genera like Schizonema, which were once supposed peculiar to the sea, have their fresh water representatives.* 102. We now come to the vittate species, which are known by the fillet-shaped markings on their disc. The species are far less numerous than in the last group, and more common in salt than in fresh water. They grow on Algz or other marine substances. Many, as Licmophora, exhibit beautiful fan-shaped groups, seated on gelatinous branched threads, the tips of which are dilated to bear the frustules. Licmophora flabellata is one of the finest microscopic ornaments of our coasts, but it is very easily injured. Climacosphenia, remarkable for the moniliform marking on its disc, has at present occurred only in New Hol- land and Mexico; and Terpsinoe in the latter country and tropical America. Several other genera occur on our coasts, as Striatella, and one or two beautiful allied objects in fresh water, as Tetracyclus lacustris, and Tabellaria flocculosa. * The genus Schizonema is not confined to the northern hemisphere. Schizonema crispum, Mont.,is found in Lord Auckland’s group and elsewhere, attached to the fronds of the smaller marine Alge. 9 130 INTRODUCTION TO CRYPTOGAMIC BOTANY, 103. The third group contains many exquisite microscopic objects, some of which may be contemplated with fresh admi- ration every time they are submitted to the magnifier. We have no longer simple, linear, or vittate markings, but the cuticle is cellular or areolate. Some are simple and disciform, as Coscinodiscus, or the discs are marked with radiating lines, as Actinocyclus and Actinoptychus ; others angular, as Amphi- tetras antediluviana, which occurs not only in a fossil state, but recent, in England and Jamaica; but curious as these are, the crown of all are such genera as Isthmia, (Fig. 7, },) and Biddulphia, both of which show, in the most admi- rable way, the mode of increase of the frustules. In some of these, every frustule is attached by a short stem to its neigh- bour. Sporangia are rarely formed. As such genera as Cosci- nodiscus and Actinocyclus, &c., abound in the Baltic, they are probably not rare in Great Britain. A few words must still be added respecting the curious Bacillaria parudoxu, the motions of which I have had more than one opportunity of observing. The frustules, which are long and slender, slip over each other, yet so as always to adhere, so that the whole mass is in motion, though at the same time several groups of frustules are moving in contrary directions. The cause of this motion is wholly unknown, but it is most probably mecha- nical, and not vital. It consists of a succession of jerks, the return being almost in the same path as the procession. The motion is more or less perfectly isochronal :—“ An obstacle is not evaded, but pushed aside; or, if sufficient to avert the the onward course, the latter is detained for a time equal to that which it would have occupied in its forward progress, and then retires from the impediment as if it had accomplished its full course.” —Smith, 1. c. The same author estimates the motion of different species as follows :—- Bacillaria paradoxa, 34 inch per second. Pinnularia oblonga, amo» es Pleurosigma strigosum, 3, ,, ‘ Niteschia linearis, mm » o Pinnularia radiosa, a» r As regards utility, it is certam that myriads of mollusca feed INTRODUCTION TO CRYPTOGAMIC BOTANY. 131 upon Diatomacee almost exclusively. Dr. Hooker tells us that he does not remember to have examined the contents of the stomach of any Salpa between the latitudes of the N. Tropic and 80° S. which did not contain the remains of Dia- tomacee. Dictyocha aculeata was universally found in the stomachs of those he opened when off Victorialand. Tripoli powder is largely used for polishing, in consequence of its being composed of silex, and some species form valuable tests of the power and clearness of microscopes. Though the greater part of Diatomacee do not readily enter into a state of decom- position, the Cymbellew form an exception, probably from comparative defect of silex. 4, CONFERVACEE, Ag. Threads articulated, simple or branched, attached or more rarely free; mostly of an herbaceous green. Cells generally longer than their diameter. Propagation by minute zoospores, or metamorphosed joints. 104. This is a vast tribe consisting of very numerous species, which are in general of very simple structure, but according to their mode of aggregation, or branching of the threads, exhi- bit extremely varied aspects. They grow in various situations, both in fresh and salt water: in thermal springs, on the bare soil, when sufficiently moist to afford nutriment, on exposed rocks, on the leaves or fronds of aquatic plants, indeed, in almost every situation in which vegetable life can be sustained; but we must not extend the term to those productions which affect mineral solutions and liquids, impregnated to a greater or less degree with organic matter, for they are mere states of different moulds, which may occasionally be detected in the act of bearing normal fruit. Nor am I inclined to include those nearly colourless species which grow parasitically on dead or diseased animals, as I feel convinced, notwithstanding the very curious phenomena they exhibit, that they are really states of Fungi. If, however, they are to be considered as true Alge, their place will be here, and I shall, therefore, describe the * peculiarities they exhibit under this head. 105. The threads are either simple or branched, and contain a nearly colourless endochrome, as in moulds; and, indeed, it was 9 * 132 INTRODUCTION TO CRYPTOGAMIC BOTANY. long since observed by Carus,* that the portions of a salaman- der which were above the surface of the water produced a Mucor, while those immersed gave rise to an Achlya. In the simple species, the endochrome in the clavate tips gradually becomes organised, producing subelliptic bodies with two lateral appendages, by means of which they are enabled to move with great celerity. These escape either by a lateral, or more frequently by a terminal aperture; and as soon as the contents are discharged, the dissepiment becomes convex, the penultimate joint swells, and gives rise to a new fertile articula- tion. This process is repeated till the vital powers of the threads are exhausted. In Achlya prolifera, however, the new sporangia are formed after the manner of the branchlets of a Cladophora, on either side, at the base of the effete joint ; and this process being repeated, we have a bifid thread. In this case also, the spores have two flagelliform appendages, and in both they give rise to new plants, sometimes germinating im situ, sometimes after the discharge of the spores, when de- tained by means of a delicate membrane, in the shape of a glo- bose head. The flagelliform appendages in Suprolegnia feraz, as observed by Thuret, are terminal, The globular sporangia, observed by the same admirable writer, with their spores, re- semble so closely those of some of the mucorine Fungi, that I should not hesitate, were there any other instance of the produc- tion of zoospores with flagelliform appendages amongst Fungi, about their removal from Algw. There is still room for further investigation, and, perhaps, some light may be thrown upon the question by examining the growth of the mould, which attacks living flies in autumn under different circumstances. It will, I think, eventually appear that the Empusa of the fly is but a form of Botrytis Bassiana, and if so, the fungal nature of these productions will be placed beyond doubt. The cellulose of which their vesicles are composed, presents a beau- tiful blue tint under iodine, and is apparently far purer than in most Fungi or Alge. 106. A large quantity of the Confervacee consist of simple unbranched articulated threads, increasing in length by con- * Act. Nov. Leop. 182 INTRODUCTION TO CRYPTOGAMIC BOTANY. 133 stant division of their endochrome, and propagated either by the rupture of the threads, or by active granules formed within their articulations, and escaping by a regular aperture. They vary in the consistency or breadth of the common tube, which is sometimes gelatinous, sometimes membranaceous, sometimes almost cartilaginous; in the length and constriction of their joints; in the abundance and depth of tint of their endo- chrome. None of the more typical species seem to form any distinct spores, apart from the zoospores. The branched Con- Jerve are very often marine, but by no means exclusively so, and sometimes attain a considerable size, The tufts which they produce vary much in density, as do their filaments in rigidity ; and in one species, which occurs in mountain streams, they are so dense as to present the appearance of solid balls of various size, resembling strongly, in some respects, the hair balls which are formed in the stomachs of some ruminating animals. One species, C. mirabilis, Ag., is so large and rigid, as to form a convenient matrix for the development of the spores of one of the red seaweeds, and hence it has been main- tained by the elder Agardh, in accordance with his notions as to the metamorphosis of one species of Alga into another, that a Conferva is capable of assuming a higher degree of organ- ization, and attaining the dignity of one of the Rhodosperms. A minute inspection, however, of specimens soon detects the fallacy, and exhibits the true nature of the phenomenon. It was said above, that the gelatinous element varies very much. This is the case both in the simple and branched species. In the former instance, the effect is only that of making the com- mon mass more slippery; but where the threads are branched, the increase of this element in quantity and consistence will at length produce fronds, according to the degree of condensa- tion, more or less comparable to those of Nostoc. We have, accordingly, delicate Draparnaldiew and Stygeoclonia, which hardly hang together, and whose masses are destroyed by any- thing except the most delicate handling; while in Chetophora, the jelly is so firm as to form globose or corniform masses, approaching even the firmer Rivulariw in consistence. In point of structure, there is no material difference, and the endochrome is frequently resolved into active granules. In 134 INTRODUCTION TO CRYPTOGAMIC BOTANY. Stygeocloniwm, however, the endochrome sometimes puts on another appearance, and is divided into new endochromes, after the fashion of some of the simple Alga, and in Cheto- phora, as first discovered by myself, when a very young botanist, near Dunstaffnage Castle, the threads are studded with globose lateral cysts. Miller* informs us that in C. tuberculosa, he has repeatedly seen two kinds of cysts, one scarlet, and constituting antheridia, the other larger, and at length producing spores. He further asserts that the female cysts germinate, that the protruded thread is at length incor- porated with the elongated antheridium, and that reproductive spores are generated by the mixture of the two endochromes. This requires confirmation, and the more so, because what he describes as the process of germination and development evidently belongs to some Rivularia. Kiitzingt considers his report as fabulous, and I am inclined to adopt his opinion. He confirms his observations, however, so far as the female cysts are concerned, Processes distinct from the branches were many years since pointed out to me, by Mr. Broome, in Cladophora glomerata, but not in such a condition as to con- vince me that they were really fruit. 107. Having once obtained a sporangial form of fruit, the transition to those plants which Kiitzing has placed in a separate section, under the name of Chantransie, is very easy. Chlo- rotyliwm, which has, I believe, been found in Great Britain, is a higher form of Chetophora, with a differentiation of certain joints after the manner of Stygeocloniwm, and fruit like that of Chetophora. The fertile joints form concentric zones, in the convex gelatinous mass, according, probably, with successive periods of growth. Chantransia, which has clusters of such cysts, is distinguished by a purple tint, and approaches Calli- thamnion in habit, while Chroolepus differs from all in its golden colour (changing, however, in the herbarium, to grey- ish green), and its affecting damp walls, trunks of trees, leaves, and other objects, and never, I believe, growing in water. The fruit of these plants wants further study. Gongroseira is at present imperfectly known, but if Kiitzing’s account be quite * Flora, 1842, p. 513, tab. 3. + Phycol. Gen. p. 325, tab. 10, fig. ii. INTRODUCTION TO CRYPTOGAMIC BOTANY. 135 correct, each joint of the terminal bundles of threads is a dis- tinct female cyst. 108. A number of Algz occur in warm climates, whose real nature is masked by an abundance of calcareous matter. These were formerly, with a few exceptions, referred as coral- lines to the animal kingdom. Like the underground Fungi, they vary much in structure, and have very different affinities. Some of these seem to be closely related to true Conferve, though often classed with Siphonee.