248 



PHARMACEUTICAL BOTANY 



SUB-CLASS A. ZYYGOMYCETES 

 (Sexual apparatus shows isogamy) 



Order i. Mucorales, the black molds, mostly saphrophytic. Ex- 

 amples: Mucor Mucedo, Rhizopus nigricans, Thamnidium,Pilobolus. 



Rhizopus nigricans (Mucor stolonifer), commonly known as 

 " Black Mold " or " Black Bread Mold," is frequently found on bread, 

 jellies, syrups, acetic pharmaceutical extracts and other substrata, 

 where it forms a dense thready mycelium bearing numerous black 

 tiny spore cases. The source of this mold is the spores, which are 

 found in the air or water with which the attacked substratum is 



FIG. 1 23 . Black mold (Rhizopus nigricans} . A , older plant ; myc, myc elia spx 

 sporangiophore; sp, sporangium; st, stoloniferous hypha produced by A, and 

 giving rise at its tip to a new plant, B. ' Greatly enlarged. (Gager.) 



in contact. Each of these, upon germinating, sprouts out and forms 

 three kinds of hyphae, vix. : rhizoidal or submerged hyphce, spor- 

 angiophores or aerial hyphce and stoloniferous hyphce. The branching 

 rhizoidal hyphae penetrate the substratum and secrete a dias- 

 tatic ferment that changes the water insoluble carb6*hydrate ma- 

 terials into a soluble sugar which passes into solution and is absorbed 

 by their walls. This, upon entering the hyphae, is converted into 

 protoplasm, and so the mold increases in size. Sporangiophores 

 or aerial hyphae . arise vertically or obliquely from a bulged-out 

 common base of the rhizoidal hyphae. Each of these when mature 



