REVIEWS.
On the Germination, Development, and Fructification of the
* Higher Cryptogamia, and on the Fructification of the
Coniferce. By Dr. WILHELM HOFFMEISTER.
Translated
by FREDERICK CCRREY, M.A., Sec.L.S. London : printed
and published for the Ray Society, by Robert Hardwicke.
WHETHER or not Linnaeus intended by the term Cryptogamia to express a doubt about the sexuality of flowerless
plants which one day might be cleared up, there is no doubt
that many of the earlier observers suspected that the same
conditions of reproduction existed in the lower as well as the
higher plants. It was not, however, till the remarkable discoveries of Suminski with regard to the fructification of ferns,
and the demonstration, not only of the existence, but of the
function of sperm-cells and germ-cells in these cryptogams,
that general attention was drawn to the subject. A host of
observers have come upon the field, and we are now almost
in a position to lay it down as a law, that throughout the
whole vegetable kingdom there is going on a reproductive
process, involving the union of two dissimilar cells—a germcell and a sperm-cell. In the lower cryptogamia there are
many cases in which this has not been demonstrated; but in
the higher cryptogamia it has been done for the whole series.
Science is largely indebted to the labours of Dr. Hofl'meister
for this result; and he has not only laboured as an original
observer, but has collected together, with an industry and
pains-taking diligence which is altogether German, all that
has been done by others on the subject. His first published
work on this subject was produced at Leipzig, in 1847. Since
that period, however, much has been done, and Dr. Hoffmeister, in the 'Transactions' of the Royal Academy of
Saxony, and in the ' Regensberg Flora/ has added much original matter to his first observations. In 1852, the Ray Society had brought before it a proposition for the translation
of Hoffmeister's work. This was, however, not entertained
at the time, as a London publisher advertised a translation of
the same. This translation, however, never saw the light;
and in 1859 Mr. F. Currey, who was himself well acquainted
with the subject, undertook to correspond with Dr. Hoffmeister on the subject of a translation of his labours on
CUKREY, ON THE HIGHER CRYPTOGAMIA.
67
Cryptogamic Botany, and the result has been the production
of this work. It should therefore he understood, that this
present volume is not a translation of Dr. Hoffmeister's original work, nor a new edition of it, but a new work. It is,
indeed, founded on the author's first work, but not only have
the papers before alluded to been added, but the author has
contributed also a large quantity of new matter, and revised!
the whole work, so that it is really a complete record of all
that is known at present. This is not only the case with the
letter-press, but also with the plates. The work is illustrated
with no fewer than sixty fine plates, all of which have been,
prepared for this work by the author, and engraved by Mr.
Tuffen West.
It would be impossible for us here even to give a sketch of
the grand series of observations of which this work is the exponent. Each group of plants belonging to the higher
cryptogamia is subjected to a searching investigation, sometimes by Dr. Hoffmeister, and sometimes by French, but more
frequently by German observers. We wish we could say that
we sometimes find the name of an English observer, but the
higher cryptogamia is not the field of English triumphs. Dr.
Hoffmeister commences with the structure of Anthoceros,
and passes on to the leafless and leafy Jungermannise. To
these succeed the Marchantiaceae, the mosses and ferns.
EquisetaceEe with Pilularia, Marsilea Salvinia, Isoetes, and
Selaginelia, are the groups which lead to the Coniferae, standing on the outside of the cryptogamic group. We may spare
ourselves any further review of the work by presenting the
author's own summary of his labours :
The comparison of the development of the mosses and liverworts on
the one hand, with that of the ferns, Equisetacese, Rhizocarpeaj, and
Lycopodiaceas on the other, discloses the most complete uniformity between
the fruit-formation on the one hand and the embryo-formation on the
other. The structure of the arehegonium of the mosses—the organ
within which the fruit-rudiment is formed—is exactly similar to that of
the arehegonium of the vascular cryptogams, the latter being that part of
the prothallium in the interior of which the embryo of the frond-bearing
plant originates. In both the large groups of the higher cryptogams
there is a cell which originates freely in the larger central cell of the
archegonium, by the repeated division of which (free) cell, the fruit of
the moss and the frond-bearing plant of the fern are produced. In both,
the divisions of this cell are suppressed and the archegonium miscarries,
unless, at the time of the opening of the top of the latter, spermatozoa
find their way to it.
Mosses and ferns therefore exhibit remarkable instances of a regular
alternation of two generations very different in their organization. The
first, generation—that from the spore—is destined to produce the different
sexual organs, by the co-operalion of which the multiplication of the primary mother-cell of the second generation, w.hich exists in the central
cell of the female organ, is brought about. By this multiplication a cellu-
68
CXJUREYj ON THE HIGHER CBYPTOGAMIA.
lar body is produced which in the mosses forms the rudiment of the fruit;
and in the vascular cryptogams, the embryo. The object of the second
generation is to form numerous free reproductive cells—the spores—by
the germination of which the first generation is reproduced. The leafy
plant in the mosses answers therefore to the prothalliura of the vascular
cryptogams; the fruit in the mosses answers to the fern in the common
sense of the word, with its fronds and sporangia. The pro-embryo, that
to say the confervoid process produced by the germinating spore of
.ost of the mosses and many of the liverworts, cannot be looked upon as
a special generation any more than the similar organ (the suspensor) in
phfenogams. It is to be remembered that when new individuals are produced
from single cells of the leaf of a moss, and also during the development
of the gemmse of many mosses, the formation of the rudiment of the
first leafy axis is preceded by the formation of a similar confervoid proembryo. This holds good as well in the mosses*'as in those liverworts
which possess a pro-embryo. When new individuals are formed from
the fragment of a leaf of Lophocolea heterophylla or of Radula complanata, the cell of the surface of the leaf which becomes the mother-cell of
the new plant produces in the former of the above-named plants a single
or double row ctf cells, and in the latter a cellular surface. In each case
the body produced is exactly similar to the pro-embryo which originates
from the germinating spore in both species.
The vegetative life of the mosses is confined exclusively to the first,
and the fructification to the second generation. The leafy stem alone
sends forth roots: the spore-forming generation draws its nourishment
from the first generation. The life of the fruit is usually much shorter
than that of the leaf-bearing plant. In the vascular cryptogams this
state of circumstances is reversed. It is true that the prothallia send out
capillary roots: this is always the case in the Polypodiaces: and Equisetacese, and frequently in the Rhizocarpeso and Selaginella:. But the prothallium lives a much shorter time than the leaf-bearing plant, which
latter, in most cases, does not produce fruit for several years. The contrasti however, is not so marked as it appears at first sight. The apparently unlimited life of the leaf-bearing moss depends merely upon continual renovation. Phenomena of a similar kind are met with in the
sprouting prothallia of Polypodiacese and Equisetacese. In the lowest
liverworts (Anthoceros and Pellia) the structure of the fertile shoots
is less complicated, and their duration little longer, than that of the
fruit. On the other hand the ramification of the prothallium of the
Equisetacese is very variable ; its life is not of shorter duration than that
of an individual shoot.
It is a circumstance worthy of notice that in the second or spore-forming generation of mosses and ferns, complicated thickenings of the cellwalls usually occur (witness the teeth of the peristome in mosses, the
capsule-wall and the elaters in liverworts, and the vessels in ferns), whilst
in the first generation these thickenings are rare and exceptional.
An unprejudiced consideration of the subject will show that the separation into two groups only of the plants comprising the mosses on the
one hand, and the liverworts (JungermannieaB, Marchantiea?, Anthocerotea?, and Ricciese) on the other, is not natural. There is no marked
feature by which these two groups can be distinguished. It is true that
a pro-embryo like that in the mosses is wanting in most of the genera of
liverworts, especially in all the leafless ones. Many leafy JungermannieEe, however, especially the true Jungermannisi, exhibit the phenomenon
i
* W. P. Schimper's excellent work, 'Recherches sur les mousses,'
renders it unnecessary for me to cite examples.
CURREY, ON THE HIGHER CRYPTOGAMIA.
69
of the conversion of the germinating spore into a single row of cells, one
of which cells, by repeated divisions in all three directions of space, becomes the rudiment of the leafy axis. This phenomenon is as well
marked as in any of the mosses. The outward form of the antheridia
and archegonia in the two groups differs very slightly. The first stages
of development of the fruit-rudiment of the mosses on the one hand and
the Jungermanniaj on the other, are, it is true, very different. In the
former the longitudinal growth is caused by the continually repeated
division of a single conical apical cell of the organ, by means of septainclined alternately in two directions; in the latter this growth is causett
by the repeated division by horizontal septa, of four cells constituting the
upper end of the fruit-rudiment. But the normal mode of cell-multiplication in the fruit-rudiment of the Marchantiea; (including the Targionieas), and of the Riccieas, coincides exactly with that of the mosses.
Lastly, Anthoceros exhibits a form of cell-multiplication of the endogoniurn which is the same as that of the punctum vegetationis of the ends
of the axes of a great number (probably the majority) of phsenogams.
The septa produced in the one apical cell of the organ, are inclined in
regular succession towards the four points of the compass. The presence
or absence of a columella, or of elaters in the ripe fruit, are points of no
characteristic value; Anthoceros has the columella, but this genus and
the Kiccieaj have no elaters. Kadula in the Jungermannieee has a vaginula, and so has Anthoceros.
Upon instituting a closer comparison between the mode of development of different forms, four types soon become conspicuous, around
•which all the phenomena hitherto sufficiently investigated may be conveniently arranged. We thus arrive at the following equivalent groups,
which are not however equally rich in the number of genera and forms.
1. Mosses according to the ordinary limits of the family, including the
Sphagnaceas.
2. Jungermannieaj; in which the leafy ones are connected with the
leafless ones by a succession of intermediate stages.
3. Marchantieje, Targioniese, and Riccieae; all intimately connected
with one another by the similarity of the earliest conditions of the fruit,
as well as by many vegetative phenomena.*
4. Anthocerotece.
The mode in which the second generation originates from the first is
much more various in the vascular cryptogams than in the others. AH
ferns however agree in the fact that the first axis of their embryo has only
a very limited longitudinal development; it is an axis of the second order
which breaks through the prothallium and becomes the principal axis;
and they all agree further in this, that the end of the axis of the first
order never forms the root. All vascular cryptogams are without main
roots; they have only adventitious ones.
In more than one respect the formation of the embryo of the Conifera
is intermediate between the higher crytogams and the phaenogams. Like
the primary mother-cell of the spores of the Rhizocarpeee and Sellaginellse
the embryo-sac is one of the axile cells of the shoot, which in the one case
becomes converted into the sporangium, in the other into the ovule. In
the Coniferse also the embryo-sac soon becomes free from any mechanical
connexion with the surrounding cellular tissue. The filling of the
embryo-sac by the endosperm may be compared with the production of
* As, for instance, the precisely similar succession of the shoots; the
separation of the tissue of the shoots into an upper layer with intercellular' cavities, and a lower layer without cavities; the occurrence of peculiar thickenings upon the inner wall of the eapillary roots, &c.
70
CURREY, ON THE HIGHER CRY2TOGAMIA.
the protliallium of the Rhizocarpese and Selaginella. The structure of
the corpuscula bears the most striking resemblance to that of the archegonia of the Salvinise, and still more of the Selaginellse. Irrespective of
the different mode of impregnation—'which in the Rhizocarpese and Selaginellae takes place by free spermatozoa, and in the Goniferje by a pollentube, in the interior of which spermatozoa are probably formed—the
transformation of the germinal vesicle into the primary mother-cell of the
new plant in the Conifers and the vascular cryptogams, only differs in
4he fact, that in the latter there is usually one single germinal vesicle
only, whilst in the former there are very numerous germinal vesicles, of
•which, normally, one only is impregnated. The embryo-sac of the Coniferse may be looked upon as a spore remaining enclosed in its sporangium;
the prothallium which it forms does not come to the light. In order to
reach the archegonia of this prothallium the impregnative matter must
make itself a passage through the tissue of the sporangium.
Moreover, the development of the pollen of the Coniferae, when dispersed, varies in a marked manner from that of phsenogams, and exhibits
vital phenomena similar to those met with in the microspores of Pilularia,
Salvinia, and Isoetes. The extinction of its sexual function (the protrusion of the pollen-tube) is preceded by a cell-formation in its interior, of
which no instance is to be found amongst monocotyledons and dicotyledons.
Two of the phenomena which have led me to compare the embryo-sac
of the ConiferiE with the large spores of the higher cryptogams, is common
to the embryo-sac of phsenogams, viz., the origin of the ovule frofti an
flxile cell, and the want of connexion with the adjoining cellular tissue.
This is very remarkable in the Rhinanthacese on account of the independent, growth of the embryo-sac. The Coniferse are closely allied to the
phsenogams in the fact that their pollen-grains develope tubes.
The phsenogams therefore form the upper terminal link of a series, the
members of which are the Coniferse and Cycadeae, the vascular cryptogams, the Muscineje, and the Characese. These members exhibit a continually more extensive and more independent, vegetative existence in
proportion to the gradually descending rank of the generation preceding
impregnation, which generation is developed from reproductive cells cast
off from the organism itself. The closing members of this series, the
Charscese, pass through their entire vegetative development in this geneoration, whilst the vital phenomena of the generation which follows
impregnation are limited to the filling with oil and starch of the newlyformed cell iu the central cell of the fruit-branch or archegonium. The
development of the latter generation in the Museineas is far more important, although in some instances, as for example in Riccia, it is very
limited in comparison with the first generation, that, namely, which precedes impregnation.* This state of things is reversed iu the Ferns, the
Equiseta, and the Ophioglossea:. From the Cbaraceje'up to these orders,
•there is an uncertainty in the different species as to the sexual function,
of the reproductive cells which are cast off from the organism itself, viz.,
* Anthoceros—which in the development of the second generation
stands very low in the scale—exhibits a remarkable analogy with the
Characese, in the fact that, as in the latter, the formation of its antheridia
commences by the growing out of the cells of the wall of an intercellular
cavity. The well-known red globules of Chara are manifestly states of
antheridia. Cavities communicating with one another are formed round
'the middle point of the hitherto solid globular mass of cells, within which
cavities the antheridia—or cellular threads in whose joints the vesicles
which produce the spermatozoa are formed—become developed.
CURREY, ON THE HIGHER CRYPTOGAMIA.
71
the spores. In these orders species nearly allied to one another are
partly monoecious and partly dioecious. Certain species amongst the
CharjE, Muscinesc, the Ferns, and tha Equiseta,* produce both kinds of
sexual organs, archegonia and antheridia, upon the same individual of
the generation preceding impregnation: the latter are always produced
before the former. In other Charaeete, Muscineae, and Equiseta, the
male and female sexual organs are distributed upon different individuals
— a separation which is very complete in certain species of mosses, and
not in others. The spores from which, in the Characese, Muscinesc, and
Equiseta, diascious prothallia are developed, exhibit no indication of the
sex of the individual to be produced from them. But there is often a
marked difference in the complete form between the male and female
individuals: the former are much smaller than the latter; they are
dwarfish. Extreme instances of this are to found, amongst mosses, in
Dicranum undulaium and Bypnum lutescens. In the Equiseta also the
male prothallia are always smaller than the females.
Lastly, the reproductive cells of the Rhizocarpece, Isoetes, and Selaginolla exhibit, according to their sex, the most remarkable differences in
their mode of development, size, and form, so long as they continue in
vital connexion with the organism belonging to the generation following
impregnation. In the Coniferre the reproductive cells differ in their
origin and formation but little from those of phjenogams; they differ
ooly hi the nature of the vegetative growth subsequent to their formation
—which growth in the Coniferee is in a high degree independent—in the
formation of the row of cells in the interior of the pollen-grain, as well as
in tlie formation of the endosperm, and of the corpuscula in the interior
of the embryo-sac.
There are so many essential points of agreement between the Coniferaj
and the phsenogams, that it is more to the point to get rid of the marked
differences in their respective processes of embryo-formation, than to
indicate in what they agree. One of these differences is the cell-formation inside the pollen-grain, but the principal one is the development of
the endosperm and of the corpuscula, a process exactly analogous to the
formation of the prothallia and archegonia of the vascular cryptogams,
aud which is entirely wanting in the phEBnogams. The whole series of
developmental processes which occur in the ConiferEe between the filling
of the embryo-sac with the cellular tissue of the endosperm and the production of the germinal vesicles in the corpuscula, is entirely passed over
in the phsenogams. Here the germinal vesicles are formed immediately
in the embryo-sac. In the phasnogams there is no vital phenomenon
analogous to the development of the prothallia and of the endosperm of
gymnosperns, just as in the cryptogams and the Coniferte there is no analogue to the endosperm-formation which takes place in so many phasnogams
after the arrival of the impregnating organ at the embryo-sac. The
breaking up of the pro-embryo of the Coniferse into a number of independent suspensors is a phenomenon of the most peculiar kind, to which
nothing amongst the vascular plants bears any resemblance,j" and to
which the division of the spore (i. e., the mother-cell of the oospores) of
* The greater number of the Chara and Muscineas, a few only of the
Equiseta, and all the known forms of Ferns and Ophioglossese.
j The formation of the pro-embryo of Loranthus Europceus out of four
l©r*gitudinal rows of cells may be looked upon as a slight indication of
this. One only of these cells, the terminal cell, becomes transformed
into an embryonie globule. (Hoffineister, in ' Abh. Kon. Sachs. Ges. d.
Wiss.,' vi, 543.)
72
CARFENTEK, ON THE MICROSCOPE.
Fucus into several cells capable of impregnation and development* is
hardly analogous, inasmuch as with the latter process the impregnation
of the free spore commences and forthwith terminates.
The Microscope and its Revelations. By WILLIAM B.
CARPENTER, M.D. Third Edition, London : Churchill.
THIS work, which has now reached its third edition, needs
no commendation from us. It is undoubtedly the best manual on the u3e of the microscope in the English language.
Nevertheless, this edition contains a large mass of new matter
which claims our recognition. The classification of the Diatomacece has been remodelled in accordance with the views of
Mr. Ralfs, and the account of that group has been considerably extended. The account of the Rhizopoda has been altogether rewritten, and that of the Infusoria has been augmented by a summary of Balbiani's recent researches on their
sexual reproduction. As might be expected from the extent
of the author's own researches on Foraminifera, the chapter
on these organisms has been rewritten and greatly extended.
Mr. Salter's researches on the teeth of Echinus, and those of
Mr. Houghton on the parasitic habits of the larva of Anodon,
have been embodied with the author's more recent views of the
structure of the shell in the chapter devoted to the Mollusca.
Additions have been made also to the account of the forms of
Annelida, and the description of the structure of the shells
of the Crustacea have been considerably modified. In the
section devoted to Insects, Dr. Hicks' researches upon their
eyes, and Mr. Beck's upon the Podura scale have been, described. Amongst the new accounts of structure among the
vertebrate animals, are those of Mr. Whitney on the circulation in the Tadpole. Mr. Rainey's important researches in
" Molecular Coalescence" are also noticed in this edition. The
work is still further improved by the addition of ten separate
plates, and twenty woodcuts. Two of the plates, representing chiefly the circular forms of Diatomacese, are on steel,
and form frontispieces to the work. It gives us much pleasure
to recognise, in so large a quantity of the new matter which
Dr. Carpenter has introduced into the present edition of his
work, the results of researches which the ' Quarterly Journal
of Microscopical Science' has been the means of introducing
to public notice. We feel that the study of this work will be
one of the best incentives to the student of the microscope to
pursue his investigations in a spirit which will enable him to
become a contributor to our pages, and a future helper of
Dr. Carpenter in the subsequent editions of his work.
* Thuret,' Ann. d. Sc. Nat.,' iv Ser., 1854, p. 273.