294 PovaH: A CRITICAL STUDY OF 
the uniform—subglobose to oval—spores, measuring 3-5 X 3-44 
or 3-5 in diameter. It is related to M. griseo-cyanus Hagem, 
from which it differs in the color of the turf, color of the sporangia, 
and the spores. It is also related to M. abundans but differs from 
it in the color of the turf, circinate ramifications, shape of colu- 
mella, and the spores. In Mucor circinelloides the spores are 
uniform, subglobose to oval, while in M. abundans they are vari- 
able, globose to short elliptical, also slightly larger. 
Mucor circinelloides was collected six times from soil, four times 
from tilled soil, once from greenhouse (potting bench), and once 
from soil in cold frame. Nos. 38, 39, 42, 43, 45, and 56. 
This species is 15-35 mm. tall on rice, without color produc- 
tion or with a pale pinkish (or ochraceous) buff (Ridgway) line 
around the edges of the top of the substratum. On grapefruit it 
is 2-17 mm. tall. It ferments dextrose but does not oxidize 
tyrosin solution. 
6. Mucor corticoLus Hagem, Ann. Mycol. So! 27778. “19019 
Forming on bread a dense, pale smoke gray to smoke gray 
(Ridgway): turf, 0.5-2 cm. tall; sporangiophores 6-16 u in diameter, 
profusely branched with long often ramified branches, terminating 
in a sporangium and with a septum above point of insertion of 
branch; sporangia encrusted with delicate crystals, globose, 51- 
94 u in diameter, dark gray; sporangium wall deliquescent, leaving 
a large or small basal membrane; columella free or slightly adnate, — 
mostly oval (a few subglobose), 31-62 27-32 u (extremes 16-62 
xX 14-51 ae aes or gray; spores subglobose to suboval, ae 
X 3-3-5 Or 4-5 m in diameter (extremes 8 X 6u or 6— 
diameter) ; nena not found (species presumably heberniadiie’: 
A single isolation of this species was obtained from soil (just 
beneath the surface) in a corn field. No. 57. This species, which 
is related to M. silvaticus Hagem, is characterized by the fact — 
that the lateral branches are usually shorter than the long, often 
bending main axis; by the usually oval columella; and by the dif- 
ferent-shaped and often larger spores. 
Mucor corticolus forms a drab gray (Ridgway) turf, 2 cm. tall 
on rice with the production of a pinkish buff line around the edges 
of the surface of the rice. It ferments dextrose but does not 
oxidize tyrosin. 
