186 COMPARATIVE MORPHOLOGY OF FUNGI 



there grow thicker buds whose tips coil spirally (Fig. 117, G). On their 

 curved outer surface there arises a branch which curves upward, coils 

 and forms a new branch, etc., so that the different branches together form 

 a serpiform main axis on whose convex sides there appear small branches 

 (Fig. 117, 1). The cells of the branches become spherical asci. 



Besides these thick buds, thinner branches coiling like tendrils grow 

 out of the ascogenous hyphae (Fig. 117, G). They elongate rapidly and 

 penetrate the sterile ground tissue, thereby making room for the develop- 

 ment of the asci. They seem to be nurse-hyphae and in this sense are 

 analogous to the haustoria of the parasitic forms and the ooblastema 

 filaments of the Florideae. 



The animation of the sclerotia proceeds gradually from the center to 

 the surface. Four to six weeks after germination, the first ascospores 

 capable of germination are found in the sclerotia while the last asci still 

 form mature spores 5 months later. The ascus walls gradually degener- 

 ate and the spores lie free inside the brown perithecial rind, which consists 

 of two or three layers of periclinal cells. By rupture or decay of this rind, 

 the ascospores are liberated. They possess a double membrane and a 

 meridional furrow like most members of the Aspergillaceae (Fig. 117, L); 

 the exospore is ruptured at germination and the endospore develops one 

 or more germ tubes. 



Onygenaceae. — This family has so far been found on animal sub- 

 strates, hoofs, horns, hides, claws, feathers, teeth, etc., and in this sense 

 forms a group sharply limited biologically. In the well-known Onygena 

 equina the fructifications (Fig. 118, 1) are up to 1 cm. in height. They 

 consist of solid homogeneous hyphal knobs which abjoint on their upper 

 surfaces so many thick-walled gemmae (Fig. 118, 2) that they seem to be 

 covered by a brownish powder. Later they are differentiated into a 

 solid stipe, composed of parallel hyphae, and a somewhat looser head, 

 consisting of radiating hyphae. Around the latter, on its outer surface 

 and toward the stipe, the hyphae intertwine to a firm pseudoparenchyma- 

 tous peridium. Their connection with the central ground tissue, however, 

 lemains to maturity when they have become capillitium. 



The processes which occur in spore formation have been too little 

 investigated. In numerous places inside the head there are formed from 

 the hyphae, two short septate branches which coil spirally into a solid 

 knot and in an unknown manner give rise to the spores. In these relation- 

 ships, they are superficially like Penicillium, but they have not been 

 studied cytologically. 



At maturity the cavity of the head is filled by a dark spore mass 

 between which run the capillitium threads, generally starting at the base 

 (Fig. 118, 4). The peridium is ruptured irregularly or around the base 

 of the head and the spores scattered. They germinate directly after a 

 resting period; this may be shortened if one places the spores in a mixture 



