TAXONOMY 
197 
common base of the rhizoidal hyphae. Each of these when mature 
bears upon its summit a spheroidal sporangium containing numerous 
small brownish multinucleate spores called endospores. The wall 
Fig. 79. — Black mold ( Rhizopus nigricans). A, older plant; myc, mycelia; sph. 
sporangiophore; sp, sporangium; si, stoloniferous hypha produced by A, and 
giving rise at its tip to a new plant, B. Greatly enlarged. (Gager.) 
of the sporangium is beset with asperites of calcium oxalate. Spring- 
ing from the base of the sporangiophores or aerial hypha? one or more 
stoloniferous hypha? traverse a portion of the surface of the sub- 
Fig. 80 . — Rhizopus nigricans. A, Young sporangium, showing columella 
within; B, older sporangium, with the wall removed, showing ripe spores covering 
the columella; C, D, views of the collapsed columella after dissemination of the 
spores. (Gager.) 
stratum and their tips, coming in contact with the substratum, 
swell up forming an adhesive organ or a p pressor him which branches 
out below into a cluster of spreading submerged hyphae and above 
