TERMINOLOGY OF REPRODUCTIVE ORGANS OF CRYPTOGAMS.
413
A REFORMED SYSTEM of TERMINOLOGY of the REPRODUCTIVE ORGANS of the CRYPTOGAMIA.
By ALFRED W.
BENNETT, M.A., B.Sc, F.L.S., Lecturer on Botany at
St. Thomas's Hospital; and GEORGE MURRAY, F.L.S.,
Assistant, Botanical Department, British Museum.1
W E have been led to the following attempt at obtaining a
symmetrical system of terminology among Cryptogams by the
undoubted fact that the anomalies at present existing greatly
retard the prosecution of the study of this most interesting
group of plants. A more striking instance of the want of
accuracy in the use of the commonest terms could not be
afforded than by observing the different meanings, often
quite irreconcilable with one another, applied by the most
approved writers to the term " spore." Thus, Le Maout and
Decaisne (Hooker's edition of 'Descriptive and Analytical
Botany,' p. 14) and Professor Asa Gray (f Botanical Textbook,' sixth edition, p. 434) speak of spores as " the analogues of seeds j " Sachs (' Text-book,' English edition, p. 203,
but modified in the most recent German edition) defines
them as " asexual reproductive cells." In direct opposition
to each and both of these definitions, Berkeley ('Micrographic
Dictionary,3 third edition, p. 327) describes the unfertilised
ova or oospheres of Fucus as spores; and Huxley and Martin (' Elementary Biology,' p. 45) call the archegonium of
Characese a spore-fruit or sporangium. A still more singular example occurs in the most recent text-book of botany
introduced to English readers (Vines's edition of ' Prantl's
Text-book" where we read on one page (p. 97) " Reproduction of Cryptogams is effected asexually by cells termed
gonidia, conidia, or spores ;" and on another page (p. 115),
" Fungi are reproduced sexually by means of spores."
The object kept before U3 in this attempt at reform has
been to arrive at a system which shall be symmetrical and
in accordance with the present state of knowledge, and which
shall, at the same time, interfere as little as possible with
existing terms. In preparing such a system it has been
impossible to avoid introducing several new terms, but these
are associated with one another on an etymological plan
which will not burden the memory of the student, while the
total number of terms in cryptogamy will be greatly reduced
1
Head at the Swansea Meeting of the British Association, Aug. 26th,
1880.
VOL, XX. —NEW SER.
E E
414
ALFRED W. BENNETT AND GEORGE MURRAY.
by the abandonment of a large number that are absolutely
useless.
So far as we know, the first systematic attempt at placing
cryptogamic terminology on a more satisfactory footing was
made by Sachs in the fourth edition of his ( Lehrbuch' (not
yet published in English), which is deserving of commendation, though it does not appear to us altogether successful.
Sachs proposes (p. 243) to define a " spore " as a reproductive cell produced " directly or indirectly by an act of fertilisation," reserving the term " gonidium " for those reproductive cells which are produced without any previous act
of impregnation. As far as Vascular Cryptogams and Muscinese are concerned, Sachs's proposal involves no change,
since he regards the spores, which are a part of the nonsexual generation, as the indirect result of the act of fertilisation which closes the sexual generation. In the Basidiomycetes he is able to retain the term spore for the
familiar bodies commonly so called, only by the assumption
—for at present it is nothing more—that the structure of
which the hymenium forms a part is the result of a
yet undiscovered process of fertilisation on the mycelium.
In the lower fungi the changes involved in the proposal
are considerable. Thus the " spores" of Penicillium,
similar as they are to those of Agaricus, can no longer be
called spores, because they do not result from an act of fertilisation, but become " conidia " or " gonidia;" and for the
same reason the familiar " zoospores " of the lower Thallophytes become " zoogonidia." It is obvious that one practical
defect of this suggestion is that it may necessitate a perpetual change of terminology as our knowledge advances.
Every fresh extension of the domain of sexual fecundation—
and it is probable that many such will take place—will
involve the removal of a fresh series of reproductive cells
from the category of gonidia to that of spores, even though
they may not be the immediate result of an act of fertilisation. Again, if the spores of Ferns and Mosses are the
indirect result of impregnation, it is difficult to say why the
term should not ultimately include all reproductive bodies
whatever, except the spores of the " apogamous ferns " with
which Farlow and De Bary have recently made us acquainted, and of other similar abnormal productions, which
are certainly not the result of impregnation, direct or indirect.
It seems a sounder principle—and is certainly more convenient to the student—to base a system of terminology on
facts which can be confirmed by actual observation, rather
TERMINOLOGY OF REPRODUCTIVE ORGANS OF CRYPTOGAMS. 4 1 5
than on unproved hypotheses. We propose, therefore, as
the basis of our terminology, to restore the term spore to
what has been in the main hitherto its ordinary signification, and to restrict its use to any cell produced by ordinary
processes of vegetation, and not directly by a union of sexual
elements, which becomes detached for the purpose of direct
vegetative reproduction. The spore may be the result of
ordinary cell division or of free cell formation. In certain
cases (zoospore) its first stage is that of a naked primordial
mass of protoplasm. In rare instances it is multicellular,
breaking up into a number of cells {polyspore, composed of
merispores, or breaking up into sporidia).
The simple term spore will, for the sake of convenience,
be retained in Muscinese and Vascular Cryptogams; but in
the Thallophytes it will always be used in the form of one
of those compounds to which it so readily lends itself, expressive of the special character of the organ in the class
in question. Thus, in the Protophyta and Mucorini, we
have chlamydospores ; in the Myxomycetes, sporangiospores ;
in the Pevonosporeae, conidiospores; in the Saprolegniese,
Oophyceee, and some Zygophycese, zoospores; in the Uredinere, teleutospores, cecidiospores, uredospores, and sporidia ;
in the Basidiomycetes, basidiospores; in the Ascomycetes
(including Lichenes), conidiospores, stylospores, ascospores,
polyspores, and merispores; in the Hydrodictyese, megasporcs; in the Desmidieje, auxospores; in the Volvocinese
and Mesocarpete, parthenospores; in the Siphonese and
BotrydiefE, hypnospores,' in the Oedogoniacese, androspores ; in the Floridese, tetraspores and octospores. The cell
in which the spores are formed will, in all cases, be called a
sporangium. It is obvious that, if greater precision is desired,
this term might be compounded in the same way as spore;
but the words thus formed would be needlessly cumbrous for
ordinary use.
The male organs of fecundation are so uniform in their
structure throughout cryptogams that very little complication has found its way into their terminology. The cell or
more complicated structure in which the male element is
formed is uniformly known among Cormophytes as well as
Thallophytes as an antheridium ; the fecundating bodies are
almost invariably naked masses of protoplasm, provided
with vibratile cilia, endowed with apparently spontaneous
motion, and bearing the appropriate name of antherozoids
or " spermatozoids." The former of these is preferable for
two reasons; from its etymological connection with antheridium, and because the use of terms compounded from
416
ALFRED W. BENNETT AND GEORGE MURRAY.
" sperm" should, for reasons to be detailed presently, be
avoided for male organs. In only two important groups,
Floridese and Lichenes,are the fecundating bodies destitute of
vibratile cilia and of spontaneous motion; in the former
case they are still usually termed antherozoids ; in the latter
" spermatia," and their receptacles " spermogonia." In
order to mark the difference in structure from true antherozoids, it is proposed to designate these motionless bodies in
both cases pollinoids ; the term spermogonium is altogether
unnecessary, the organ being a true antheridium.
A satisfactory terminology of the female reproductive
organs presents greater difficulties, from the much greater
variety of structure, and the larger number of terras already
in use. The limits we have placed to the use of the term
" spore" and its compounds require the abandonment of
" oospore " for the fertilised ovum or oosphere in its encysted
state (enclosed in a cell-wall), anterior to its segmentation
into the embryo; and this is the most important change
involved in the new system.
In devising a term which shall include all those bodies
which are the immediate result of impregnation, it was
necessary to take two points specially into account. Firstly,
the term must be capable of defence on etymological grounds;
and secondly, it must, like spore, be capable of ready combination. After much consideration we have decided on
proposing the syllable sperm. No doubt the objection will
present itself that the Greek (jnip/xa, like the Latin" semen,"
and the English " seed " (as used, by old writers), while
originally meaning the ultimate product of fertilisation,
came afterwards to signify the male factor in impregnation;
and hence, in zoology, terms derived from these roots are
used for the male fertilising bodies. But the objection applies
to a much smaller extent to phyto-terminology. Some terms
compounded from " sperm," as gymnosperm, angiosperm,
&c, are already familiarly in use in a sense similar to that
•we would indicate; while of those used in the reversed
sense, " sperm-cell," for antherozoid or pollen-grain, has
never come into general use in this country; " spermatozoid "
is easily replaced by antherozoid; " spermogonium" is
simply a peculiar form of antheridium, and "spermatium"
has already been referred to. Accepting this term as the
least open to objection of any that could be proposed, it will
be found to supply the basis of a symmetrical system of terminology, which will go far to redeem the confusion that at
present meets the student at the outset of his researches.
For the unfertilised female protoplasmic mass the term
TERMINOLOGY OF REPRODUCTIVE ORGANS OF CRYPTOGAMS. 4 1 7
oosphere is already in general use ; and, though not all that
could be desired, it is proposed to retain it, and to establish
from it a corresponding series of terms ending in sphere.
The entire female organ before fertilisation, whether unicellular or multicellular, is designated by a set of terms
ending in gonium, again following existing analogy.
As will be seen from another paper presented to the Association, we propose, in our forthcoming " Handbook of
Cryptogamic Botany," to make the primary division of the
Thallophytes into the three great classes of Protophyta,
Fungi, and Algse, each of the two last being again divided
into three parallel series of Zygospermeae, Oospermese, and
Carpospermesei, corresponding nearly to Sachs's Zygosporese,
Oosporese, and Carposporese. In the Zygomycetes and
Zygophycese, the conjugated zygospheres, or contents of the
zygogonia, constitute a zygosperm ; in the Oomycetes and
Oophycese, the fertilised oosphere, or contents of the oogonium, is an oosperm; in the Carpophycese, the fertilised
carposphere, or contents of the carpogonium, constitutes a
carposperm. In this last class the process is complicated,
being effected by means of a special female organ, which, to
keep up the etymological analogy, may be called a trichogonium rather than a " trichogyne." The ultimate result
of impregnation is the production of a mass of tissue, known
as the cystocarp (or " sporocarp "), within which are produced the germinating bodies, which must be designated
carpospores, since they are not the direct result of fertilisation, but which must be carefully distinguished from the
so-called " carpospore "—properly an archesperm—in the
Characese. Any of these bodies which remains in a dormant condition for a time before germinating will be a
In the Zygospermese it is no doubt the case that the two
conjugating bodies are really a zygosphere and an antherozoid (or pollinoid) ; but, as they are at present absolutely indistinguishable, it seems best to sacrifice theory, and call
them both zygospheres.
It may be mentioned, by way of completing the analogy,
that a precisely analogous set of terms will be proposed for the Cormophytes (Characese, Muscinese, and
Vascular Cryptogams), throughout which the fertilised
archesphere, or contents of the archegonium, is called an
archesperm. The latter term may be objected to as nearly
identical with " archisperm," used by Strasburger and
others as a synonym for gymnosperm ; but the term has not
come into general use, and no confusion between the two
418
ALFRED W. BENNETT AND GEORUE MURRAY.
seems possible. In the proposed system zygosperrn will
replace Strasburger's " zygote," and the " gametes " of the
same writer will be zygospheres ; while his " zoogametes " or
" planogametes " must enjoy the somewhat cumbrous name
of " zoozygospheres," the prefix " zoo" or suffix " zoid "
being always used to denote an apparently spontaneous
power of motion.
In the Basidiomycetes, Ascomycetes, and some other
classes of Cryptogams, the entire non-sexual generation
which bears the spores is frequently called the " receptacle,"
a term which is for several reasons objectionable. In the
first place it has no meaning etymologically in this connection; and secondly, it suggests a false analogy with the
receptacle in flowering plants, a structure which supports
the sexual reproductive organs. A convenient expression
for that portion of the non-sexual generation which bears the
spores is the fructification, corresponding to the German
equivalent " Fruchtkorpev," and already popularly used in
this sense in the case of mosses, as well as for the sori of
ferns. Except, as far as is yet known, in the case of the
Basidiomycetes, the fructification is always the result of impregnation ; and, according toReess, Eidam, and others, the
same is the case also in that class of fungi.
To illustrate the simplification effected in cryptogamic
terminology by the proposed reform, two comparative tables
are appended; and the following list is given, which enumerates some of the terms in more frequent use by various
writers as respects Thallophytes and Characeec, all of which
are disused in the proposed system.
Non-sexual organs,—Gemma, conidium, gonidium, endogonidium, zoogonidium, macrozoospore, acrospore, ectospore,
swarrnspore, pycnidium, perithecium, apothecium, theca,
receptacle.
Male sexual organs.—Spermatozoid, spermatium, spermogonium, globule.
Female sexual organs.—Oospore, zygospore, zygogonidium,
zygozoospore, zygote, gamete, planogamete, aplanogamete,
ascogonium, nucule, sporocarp, ceramidium, coccidium,
favella, favellidium, sphaerospore.
TERMINOLOGY OF KEPBODUCTIVE ORGANS OF CRYPTOGAMS.
419
Modes of Fertilization in Cryptogams.
Conjugating Bodies.
Zygogouia, containing Zygospheres.
ZYGOSPEKMEJS.
(fertilised) Zygosperm.
Male Organ.
Female Organ.
Antheridium, containing
Oogonium, containing
Antherozoids or \
Pollinoids.
f
=
Oosphere.
OOSPERUEiE.
(fertilised) Oosperm.
CAEPOSPEEMEJE.
Antlieridium, containing
Antherozoids or")
Pollinoids.
i
=
CORMOPHYTA.
Antlieridium, containing
Antherozoids
Carpogonium, containing
•
n .
Carposphere.
(fertilised) Carposperm.
Archegoninm, containing
Arcuesphere,
(fertilised) Archesperm.
Productive Organs of Thallophytes.
. Female.
PHOIOPnYIA.
Zoospore.
Sporangiospore.
MYXOMYCETES.
MTJCOMXI.
PEKONOSPOBEiE.
Zygogonium.
Zygosphere.
Zygosperm.
fOogoniuin.
Oosphere.
j Oosperm.
SAPEOLEGSIEiE.
UEEDINBiE.
Non-sexual.
Chlamydosnore.
Sporangium.
Chlamydospore.
Sporangiospore.
Sporangium.
Conidiospore.
Zoospore.
Zoospore.
Carpogoniiim.
Carposphere.
Carposperm.
Teleutospore.
Aecidiospore.
Uredospore.
Sporidium.
Telentospore.
Sporidiura.
BASIDIOMYCEXES.
Basidiospore.
Sterigraa.
Basidium.
420
ALFRED W. BENNETT AND GEORGE MURRAY.
ASCOMYCETES,
Trichogonium.
including LICHENES. Pollinodium.
Conidiospore.
Stylospore.
Ascospore.
Polyspore.
Merispore.
ZYGOPHYCE*.
Zygogonium.
Zygosphere.
Zoozygosphere.
Zygosperm.
Hypnosperm
(Hydrodictyete
Zoospore.
Megazoospore (Hydrodictyere).
Auxospore (Diatomacese).
Hypnosporangium}^,.^;^
Hypnospore
Parthenospore (Mesocarpese).
OOPHYCB^;,
Oogonium.
Oosphere.
Oosperm.
Conceptacle.
Hypnosperm.
Zoospore.
Partlienospore (Volvocineas).
Androspore (Oedogoniacesc).
Hypnospore (Siphonete).
CARPOFHYCE/E.
Carpogonium.
Carposphere.
Caiposperm.
Trichogonium.
Tricliophore.
Cystocarp.
Zoosporangium.
Tetraspore.
Octospore.
Carpospore.