Introduction to cryptogamic botany

Introduction

TO

ORYPTOGAMIC BOTANY.

4 fi \. S ae a.

BY THE

REY. M. J. BERKELEY, M.A, F.LS.

KAARPLPAAL AARP LASS

WITH 127 ILLUSTRATIONS ON WOOD, DRAWN BY THE AUTHOR,

LONDON:

‘sem, H. BAILLIERE, PUBLISHER, 219, REGENT STREET; AND 290, BROADWAY, NEW YORK, U.S.

[ THE RIGHT OF TRANSLATION Is RESERVED.

TO

CORRESPONDING MEMBER OF

Whe Academivs of Sriewre of Paris, Berlin, Xe.,

THIS WORK IS DEDICATED,

[IN TOKEN OF

THE MOST SINCERE GRATITUDE AND RESPECT,

BY HIS OBLIGED SERVANT,

M. J. BERKELEY.

ERRATA.

Page 4, for Cycads read Zamic. 8, for Hastig read Hartig. 10, for Browne read Broome. 27, for paradoran read paradozum. 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 Geppert read Berendt.

ADDENDA.

Page 77. Meneghini has figured annular vessels in Sargassum linifolium See Alghe Italiane, &c., Tay. 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 perithecia are termed pyenidia, 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 notinclosed 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.

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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 Oryptogamic 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 information, 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 Micrographie 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 completely 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 Einleitung 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 sight 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.

Vili

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 ascribable to carelessriess. An incredible amount of labour has been bestowed upon its preparation, in the examination 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 more 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 information 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 caleulated 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.

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 apprehended 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 misplaced, 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 Nymphca will be supposed to have something to do

: ¥ 1

Introduction To Cryptogamic Botany

bo 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 erand class,+ more distinctly indicated perhaps even than the other two, though composed of parts still more widely differmg 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 @Mce 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 Phenogams amongst which they grow, and

* After a patient examination of germinating plants, and an attentive 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 Gymnogens) as 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. Ifthe 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 multitudinous 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 production of perfect seeds.» He will indeed be liable at first,

Fig. 1.

A single leaflet of Stangeria paradoxa, 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 * 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 distinguish 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, perhaps, 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 filictfolia, from the Kew Gardens.

the bipimnate 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-

Piln 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. 5 temads (Fig. 3), as Algze or Liverworts (Fig. 4);* and again,

Fig. 3. a Apinagia pusilla, Tulasne. b Mniopsis Hookeriana, Tul. e 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 Deutschland’s Flora, Tab. xxxiii., Nos. 26, 27, of Blandovia striata, Cda. Dicrea Wallichii, Tul. was described by Taylor under the name of Polypleurum orientale, Tayl. 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.

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 Rafflesia, 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 anothet® The difficulty is just as great when in extensive 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 factiis exhibited in the vegetable kingdom, because for the most part they have only very imperfect materials, and therefore suppose that the distinctions between species are far more definite than they really are. Ina 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 hairsplitter 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 opportunities 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 productions are evidently distributed. In all these cases, definitions 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 Hepatice; 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 in all plants the early embryonic state consists of cellular tissue only, and

Fig. 5.

a Threads from peridium of Batarrea phalloides, P. magnified, b A portion more highly magnified. c 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-ascertained 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 Algse, may be consulted on this point. Hastig figures this spiral pleurenchyme under Pinus pumilio. — - :

+ A ready example to the contrary may be found in the fruit of the Horse Chesnut.

INTRODUCTION TO CRYPTOGAMIC BOTANY. 9 part, and not to their fruit ; but even then the law is far from - general. - In such, Diatomacee 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’s} views of the development of Exogens be adopted, the mode of increase of the woody tissue resembles perfectly that of many Conferve, 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 doubtful, 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 differences 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.

t Trécul in Ann. d. Sc. Nat. Sér. iii., vol. 17, p. 250; vol. 19, p. 157, 258. .

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 Alge, in the first instance by Thuret,* and afterwards by Pringsheim+t and his followers. Where the flagelliform appendages characteristic 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, or 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’observations sur les Anthéridies des Algues. Ann. d. Sc. N at., Sér. iv., vol. 2, p. 273. |

} Pringsheim in Monatsbericht der Kin. 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 Jower Algs and of such fungi as Antennaria Robinsonti, 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, &c. (Fig. 6), indicated by spots or apertures in the outer integument, through which the germinating 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.t 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 Prodromus, 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 Olintonia, much reduced as in endogens, or obsolete as in Cuscuta, 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.

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 necessary is uncertaint 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 Phznogams; 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 Cytisus 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 individual; 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 characters 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 exhibit a trace of the members of which it is constituted. No one would then hesitate to consider it an individual. Patches of moss might become confluent in the same way, but the commonest observer would at once see that they were mere masses consisting of a thousand or more [a plants, interlaced indeed, and almost inextricable, but still distinct.

INTRODUCTION TO CRYPTOGAMIC BOTANY. 13 flowers of two distinct species on the same branch intermixed with others partaking 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 irreconcilable with their truth, are to be regarded as true: visions which are now happily exploded by the brillant observations of Trécul.*

8. We have now then arrived at some general notion of the large mass of plants known under the name of Cryptogams, 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 Phenogams 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-