CHAPTER V.—COMPARATIVE REVIEW.—ASCOMFYCETES. 235 
spermatia which must be supposed to be abjointed portions of such branches, are 
in function male sexual organs, and that the archicarps are female sexual organs, and 
that the Fungi which produce them possess the power of sexual propagation. 
This statement is not admissible in the case of all the other forms furnished 
with homologous members. Resting on what we know, we may suspect’ that 
in Polystigma the trichogyne and spermatia behave in the same way as in Collema, 
but we have no proof of the necessary material union. In Gymnoascus and the Ery- 
sipheae, especially Podosphaera, the two organs appear with the same constancy, 
one might say with the same morphological necessity, as in Pyronema, and the 
possibility of a material union of the protoplasmic bodies is not excluded by the 
known facts. The antheridium, it is true, always remains separated from the archi- 
carp by a membrane which, as far as we can see, is not perforated, but it 
is closely attached to it, and dissolved or very finely comminuted substance may 
pass through the membrane, as must be assumed in the case of the fertilisation of 
Angiosperms. But after all nothing is proved about the matter; the constant 
contact of the antheridial branch proves nothing; the envelope is constantly in the 
same position; we cannot get beyond probabilities and possibilities. Beneath the 
level of probability we arrive at last at species like Melanospora parasitica and 
Ascobolus, which needs revision however in this respect, with a beautifully developed 
carpogonium, but with the attachment of the antheridium not constantly or certainly 
observed. The conclusion on the whole is, that some of the forms in question have 
sexual organs which can be shown to fulfil their functions, others have organs 
perfectly homologous with the first, but with the sexual function not certainly 
ascertained or certainly wanting. 
We have secondly to enquire after the homologies of the Ascomyeetes, in which 
there is no distinct archicarp, as far as we at present know, when the sporocarp 
begins to appear. We will consider first the extreme cases, Pleospora and Claviceps. 
Here the question is, are the parts in these species to be considered as really homo- 
logous with those of the same name in the other series which has archicarps, or only 
as very similar to them in form and function ; or, expressed in terms of the phylogeny, 
do these Ascomycetes belong to a single series of forms descended from the same 
stock, or to a/ least two series descended from different stocks only with analogous 
ultimate construction? We can only advance probable arguments in deciding between 
these alternatives, but these are against the second of the two and in favour of the 
unity of the Ascomycetes. First of all the difference alleged is the only one, while 
they agree together in all other points of importance to a degree which is else- 
where found only in allied forms, and not in those which are merely analogously 
developed. Secondly, no other close affinity can be found for the Ascomycetes which 
have no archicarps than that with the others; and they must have some relation of 
the kind, some connection with other forms. Thirdly, the extremes are evidently 
connected together by intermediate forms. The first of such forms is to be found in 
Melanospora parasitica with its beautifully developed carpogonium but inconspicuous or 
absent antheridium ; other like phenomena appear to occur occasionally! in the series 
of the Sordarieae, and these therefore claim the attention of observers. Sclerotinia also 

1 See also Zopf in Sitzgsber. d. Brandenb. bot. Ver. 1877. 
