246 



THE LOWER FUNGI— PHYCOMYCETES 



Rhizopus disappears entirely, and Hydrophora Tode includes the 

 species usually placed in Mucor. 



Fig. 82. — Rhizopus nigricans Ehrenberg. (a) Fascicle of eporangiophores 

 arising opposite the rhizoids, and connected by a stolon with another group. 

 (6) Sporangium enlarged to show columella and spores. {After Atkinson 1908.) 



Fig. 83.^ — Rhizopus nigricans Ehrenberg. (a) Adjacent hyphae united by 

 young progametangia. {b) Progametangia. (c) Gametangia and suspensors. 

 {d) After fusion of gametangia. (e) Mature zygospore. {Original.) 



For a taxonomic separation of species consult Lendner (1908) 

 and Hanzawa (1914: 230). 



6. Spinellus van Tieghem (1875: 66). 



Vegetative mycelium buried in the substratum, consisting of 

 delicate, hyaline hyphae; aerial mycelium well developed, brown, 



