CHAPTER V.—COMPARATIVE REVIEW.—-ASCOMYCETES.—SPHYRIDIUM. 221 
and form asci. No paraphyses are formed. The whole process shows great simi- 
larity with that described by Bauke in Pleospora. 
The formation of the perithecia in the stroma of Epichloé is undoubtedly very like 
that of Claviceps; so probably, according to Fisch, is the same process in Cordyceps 
(C. militaris, C. ophioglossoides, and C. capitata). The perithecia also of Nectria, 
according to Janowitsch’s earlier observations and of Cucurbitaria according to Bauke’s 
report, are formed without initial archicarps, antheridia, or spermatia, but simply by late 
differentiation of portions of the stroma which were at first uniformly parenchymatous 
or consisted of closely woven hyphae; in both genera there is also a dissolution of 
the original central pseudo-parenchyma to make the inner cavity and a formation of 
paraphyses between the asci. But these older investigations require to be repeated at 
the present day. R.Hartig’s account of Nectria mentioned above (page 217) is specially 
deserving of attention ; he suspects that the perithecia in N. ditissima.are produced from 
archicarps which are formed originally superficially on the stroma under a covering 
of gonidia-forming hyphae, and are then inclosed by branches from adjacent hyphae, 
and that in conjunction with these latter hyphae they then give rise to the primordial 
pseudo-parenchymatous formations from which Janowitsch’s investigation sets out. 
The possibility of similar processes is not entirely excluded by the accounts which we 
possess in the case also of Epichloé. 
15. Van Tieghem gives the name of Ascodesmis to two small Discomycetes 
which in the full-grown state look like small Ascoboli and are distinguished by 
reticulate thickenings of their spore-membranes. He describes the development 
of their apothecia from specimens cultivated on microscope-slides in the following 
manner. A slightly bent lateral branch rises from a cell of a filament of the mycelium, 
and, after a short increase in length, branches in a pseudo-dichotomous manner ; this 
mode of branching is repeated through several orders in planes which intersect each 
other alternately, and the successive branches have a similar curvature. At length they 
all become woven together into a cushion of compact pseudo-parenchyma, which is 
attached on one side to the mycelial filament by a short stalk. Then closely crowded 
paraphyses shoot out from the superficial cells on the opposite side, and then the asci 
one after another from the same surface and between the paraphyses. We are not 
told whether any difference appears between the ascogenous cells and those which 
form paraphyses, or if the asci at least which follow one another spring from distinct 
ascogenous hyphal branchlets. 
16. The apothecia of Sphyridium fungiforme, S. placophyllum and 
Cladonia Papillaria consist in the mature state of close-set paraphyses and of asci 
inserted between them, and the asci arise from distinct ascogenous hyphae in the 
hypothecium. According to Krabbe?! the commencements of these apothecia are 
peripheral shoots from the outer surface of the thallus, and the layer of paraphyses 
first makes its appearance and afterwards the ascogenous hyphae with the asci. No 
trace was observed of a distinct carpogonium or archicarp, as the source of the 
ascogenous hyphae, or of any co-operation of spermatia; on the contrary, the 
ascogenous hyphae are branches of ‘ordinary’ hyphae, hyphae, that is to say, which 
aré not distinguishable from vegetative hyphae and from those which form 

1 Bot. Ztg. 1882. 
