214 DIVISION II,—COURSE OF DEVELOPMENT OF FUNGI. 
the thallus which is in their way, till at length the space between the excipulum and 
the surface of the thallus is filled by an incipient hymenium consisting of paraphyses 
standing side by side with no gaps between them. The ascogonium has meanwhile 
at first slowly followed the growth of the excipulum by intercalary growth accompanied 
by a loosening of the turns of the spiral. As the development proceeds the asco- 
genous hyphae sprout from it, and spread their abundant ramifications through the 
zone of origin of the paraphyses, the subhymendal layer, in essentially the same 
manner as in Ascobolus, and thrust the asci as branches of the last order one 
after another in between the paraphyses (Fig. 102). 
The species of Physma also examined by Stahl agree with Collema except 
in the following peculiarities. The archicarps here spring from the hyphae which 
form the protuberant base of the spermogonia, from four to eight on each spermo- 
gonium. The ascogonia are but slightly curved and are inclosed in the hyphal 
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FIG. 102. Collema anicrophyllum. Median section through a young apothecium imbedded in the thallus; 4 and g as 
in Fig. 108, d—c excipulum and hypothecium ; from the latter proceed crowded upright paraphyses, between which asci are 
beginning to be formed on the ascogenous hyphae above the hypothecium. After Stahl, Magn. 530 times. 

weft of the wall of the spermogonium, and the trichogynes protrude beyond the outer 
side. The discharge of the spermatia of a spermogonium coincides as a rule with 
the completion of the trichogynes which belong to them, and these become covered 
with the spermatia adhering to them. Then paraphyses grow out from the wall 
of the spermogonium into its now empty cavity, displacing the sterigmata, and soon 
fill it up in the form of a tuft of filaments which converge towards the former orifice 
and are so closely packed as to leave no spaces between them. Into the subhymenial 
zone, which is thus defined, ascogenous branches shoot out from the archicarps and 
push the asci in between the paraphyses; the spermogonium is thus converted into 
the apothecium. 
Borzi has repeated Stahl’s observations on other species of the Collemaceae with 
confirmatory results. 
g. Incipient sporocarps or archicarps, of doubtful character and requiring a 
fresh examination, have been assigned by Woronin to Sphaeria Lemaneae, Sordaria 
