Fungous Flora op the Soil 449 



Sporangia green-black, 50-80/x usually 6ojU, with diffluent membrane, 



spores 4-10 by 2.5-5/i M. hiemalis Wehmer 



Sporangia brownish, 30-80/x mostly 6oju, with nondiffluent membrane, 



spores 2-3 by 1 . 5M M. microsporus Namyslowski 



Sporangia gray, 80-95/i, with diffluent membrane, spores 8.5 by 4.5/1 



M. adventitius Oudemans 

 3. Sporangiophores 1-4 centimeters long, spores mostly cylindrical, 



5-7 by 2.5-3 • Sm M. strictus Hagem 



Sporangiophores 2-15 centimeters long, spores 6-12 by 3-6/1 



M. mucedo (Linne) Brefeld 

 Racemo-mucor 



Branching indefinite, in groups or clusters or in corymbs. 



1. Sporangiophores at first erect, but soon falling 2 



Sporangiophores always erect 3 



2. Branches of the sporangiophores ascending; sporangia 40-60/1, bright 



yellow, breaking, leaving a basal collar. . .M. Christianiensis Hagem 

 Branches of the sporangiophores mostly reflexed; sporangia 15-45/1, 

 falling closed and remaining intact for a long time 



M. dispersus Hagem 



3. Spores very unequal (mixture of numerous small spores with others 



twice as large), oval or subcylindrical, 4 by 2/1 or 5 by 3/1 to maxi- 

 mum 8 by 6/1 M. sylvaticus Hagem 



Spores reasonably equal 4 



4. Membrane of the sporangium nondiffluent M. racemosus Fresenius 



Membrane of the sporangium diffluent 5 



5. Species very large, 6-8 centimeters high (always over 2 centimeters); 



spores 9-12 by 4.2/< M. flavus Bainier 



Species much smaller, never exceeding 2 centimeters high ; spores 

 5-7 by 2.5-3.5/1 M. genevensis Lendner 



Cymo-mucor 



Sporangiophores branched in sympodial C3rmes. 



1. Sporangiophores nonerect, incurved, forming a cobwebby network, 



1 . 5 centimeters high, ending in a large sporangium and producing 

 at a short distance below more or less closely clustered branches; 



secondary branches sometimes dichotomous 2 



Sporangiophores circinate .' 3 



Sporangiophores straight, not circinate 6 



2. Spores average 8/1 M. botryoides Lendner 



Spores average 6/1. ... M. botryoides var. minor 



3. Sporangiophores never much surpassing i centimeter; spores oval, 6/1 



being maximum length 4 



