12 MUCORACEAE 



1. Mycelium producing a single fruit-body Polyphagus 7: 302, S. 85 



2. Mycelium producing several fruit-bodies Urophlyctis 7: 303, S. 85 



Subfamily Zygochytriae 



SCHROETER 87 



Mycelium one-celled, upright, branched, producing zoospores and zygospores ; 

 zoosporangia single on ends of the branches, opening by a lid, zoospores one-ciliate ; 

 zygospores produced by the fusion of the end-cells of conjugating tubes, growing 

 into a filament upon germination; intermediate between Chytridiaceae and Mu- 

 coraceae. 

 A single genus Zygochytrium 7: 294, S. 87 



Order 4. SPIROGYRALES 



Typically one-celled or simple filamentous algae, without zoospores ; sexual repro- 

 duction by the conjugation of similar gametes; two fungous families. 



Family 8. MUCORACEAE 



ScHEOETER iiQ, 7 : 182, 9:335, 11:239, 14:432. 16:383, 17: 494 

 Saprophytes, rarely parasites, with a well-developed branching mycelium in which 

 cross-walls are absent ; propagation by spores (conidia) arising within sporangia, the 

 latter apparently reduced to chains of conidia in one family ; reproduction by the 

 union of the end-cells or gametes of conjugating tubes. 



Key to the Subfamilies 



I. Sporangia always present, conidia sometimes present 



1. Columella present; zygospore naked or with a few appendages 



a. Wall of the sporangium homogeneous, not cuticularized, diffluent 



Mucorae 



b. Wall cuticularized and persistent above, thin and diffluent below 



Pilobolae 



2. Columella absent ; zygospore enveloped in a dense covering 



Mortierellae 



II. Sporangia rarely present, conidia always present 



1. Conidia solitary; zygospore arising directly from the gametes 



a. Sporangia present Choanophorae 



b. Sporangia lacking Chaetocladiae 



2. Conidia in chains ; zygospore arising from outgrowths of gametes 



Syncephalidae 



Subfamily Mucorae 

 7: 184, S. 123 



Mycelium similar throughout or consisting of aerial and nutritive parts ; sporan- 

 gia alike or of two sorts, primary and accessory, the former with columella, the lat- 

 ter mostly without one; zygospore naked or with separate appendages arising from 

 the suspensors. 



