CONFERVOID FILAMENTS OF MOSSES. :>83 
marks between many Confervoids is very questionable, and thev have doul>tless led to 
much misconception and incorrect assumption. These plants being formed of very simple 
parts, their characteristics are necessarily ambiguous, and hence the difficulty of fixing 
their true position; and this is especially the case in those kinds which are composed of 
a single cell, whether belonging to those which have been designated by Braun as 
" true unicellular Algae," or " pseudo-unicellular," or to those which are multicellular, 
but which spring at some portion of their history from a single v» ei alive cell (spore, 
gonidium, &c). 
3. The third subject to be dwelt upon has already received some attention at the com- 
mencement of this paper, — namely, that the function and development of the cells 
separated from the filaments are evidently analogous to those of the gonidia of Lichens 
and also of many Alga?, and therefore the term gonidia* may be rightly applied to 
them. It is the office of the filaments to produce these gonidia; or perhaps it should 
rather be considered that each filament, in its most marked condition, is a series of 
gonidia developed in a linear form, each division of which is capable of becoming a 
gonidium : and this mode of viewing these filaments points out the analogous condition 
observable in the moniliform filament of gonidia in Collema, each cell of v hich, although 
generally segmenting linearly on the binary plan, can at any time assume the other 
actively segmenting states, as has been pointed out by me in the papers above alluded to. 
The position in which these filaments stand towards the rest of the plant is peculiar. 
Looking at them as a basis upon which the axis producing the organs of the true fruc- 
tification is supported, they have at first been considered as the homologue of the pro. 
thallium of Ferns; but they really represent only a portion of that organ. They cor- 
respond, indeed, only to the few confervoid cells first generated from the spore; while 
the heart-shaped Marchantia-expansion of the prothallium of the Fern is to be con- 
sidered as corresponding to the stem, leaves, antheridia, and arelngonia in the Mosses. 
They differ also in the respect of producing gonidia, at least so far as is kno^n at 
present, although it is quite possible (judging from analogy) to suppose that gonidia 
may be found to be produced from this position of the prothallium of Ferns, under 
certain conditions. Compared with Fungi, they seem to hold an analogous condition 
to the mycelium, more particularly apparent in the simpler forms of the Jbjphomycetes ; 
for it is questionable whether the so-called fruit of these Fungi is not rather analogous 
to the gonidium than to the growth which results from impregnation. It is at pre- 
sent uncertain whether any antheroids exist in the Fungi, and, if they do, whether the 
spores take any part in true fecundation. 
It is very necessary to bear in mind that the confervoid filaments play a yen- im- 
portant part, if not the most important, in the disseminating of -Mosses - — ■» 
than has been generally supposed. Considered quite independently of their powers oi 
producing gonidia, they tend to spread the order in eyery direction and cover very much 
larger surfaces than the species from whence they are derived could do by gamit ^repro- 
duction, whereby, simultaneously as it were, large spaces, even many feet m length, are 
• The distinction between - gonidium - and - spore" as marked out by Brann in ■ Rejuvenescence in Nature,' is 
borne out here and in the Lichens much better than in the Algae. 
much more so 
VOL. XXIII. 
4i 
