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 subhymenial 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 



FIG. 102. Collema microphyllum. Median section through a young apothecium imbedded in the thallus; h and g as 

 in Fig. 101, b — 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. 



9. Incipient sporocarps or archicarps, of doubtful character and requiring a 

 fresh examination, have been assigned by Woronin to Sphaeria Lemaneae, Sordaria 



