MUCOR 



237 



later conspicuous, dark brown or black, spherical sponmgia 

 {sp.) appear at the ends of relatively thick upright hyphre, 

 which in some species are branched. An ally of Miicor 

 [Rhizopus stolonifer), that occurs very commonly on stale bread 

 and horse dung, spreads very rapidly by hypha resembling 



Fig. 125. — Mucor. a, mycelium, slightly magnified, showing two of the 

 long-stalked sporangia (sp.) ; 6, sporangium, much enlarged, in 

 optical section, showing the numerous spores and the central column 

 (Co.) ; c, dehisced sporangium in which only the column and a 

 small part of the wall remains ; d and e, conjugation of gametes (g.) ; 

 /, mature zygospore, (n, 6, and/after Brefeld ; cafter Sachs; dande 

 after De Bary.) 



minute Strawberr}' runners, at the end of each of which a tuft 

 of absorptive threads and sporangia is produced. 



The wall of each sporangium (Fig. 125, h) is beset with 

 numerous minute needles of oxalate of lime, whilst the swollen 

 end of the hypha below projects into the cavity as a central 

 column [Co.) ; between this and the wall are many small thick- 

 waUed spores embedded ina mucilaginous substance. The latter 

 swells in the presence of moisture, and thus contributes to the 



