300 PovAH: A CRITICAL STUDY OF 
This species forms a 14-20 mm. tall, gray turf on grapefruit 
and on rice a 10-20 mm. tall, pale smoke gray to smoke gray 
(Ridgway) turf. It ferments dextrose but does not oxidize 
tyrosin. 
14. Mucor HIEMALIS Wehmer, Ann. Mycol. 1: 37. f. I-9. 1903 
orming on bread a dense, grayish white (Ridgway) turf 
tinged tilleul buff, 1-3 cm. tall; sporangiophores 16-20 in di- 
ameter, at first simple or, more often, once or twice (exceptionally 
up to six times) branched, with a septum immediately above 
point of insertion of branches, all of which terminate in a sporan- 
gium; sporangia globose, 60-75 yw in diameter (extremes 30-100 yp), 
at first yellowish becoming dark gray with a greenish tinge at 
maturity; sporangium wall deliquescent, leaving a basal mem- 
brane; columella free, globose to subglobose, 30-50 u in diameter 
(extremes 20-55 u), hyaline; spores variable in shape and size, 
subfusiform, subreniform, narrowly oval, subelliptical, 4-8 
X 2-4 u (a few 8-9 X 4-6 yu), hyaline; zygospores not found (species 
heterothallic). [PLATE 20, FIGs. 7—10.] 
This species was isolated from various types of soil, from 
several kinds of dung, and from decaying mushroom. Nos. 4, 5, 
6,43, 72) and 74. 
This agrees with Wehmer’s description in general although the 
sporangia and columella are slightly larger, and branching is 
frequent. Both of these differences may be due to the influence of 
the substratum, as Wehmer has pointed out the variability of this 
species. The spores are characteristically variable, reniform 
being a common shape. 
Mucor hiemalis exhibits the following cultural characteristics: 
on rice it forms a slightly yellowish, gray turf, 10-25 mm. tall 
(with a pinkish buff to orange buff line at margin of the upper 
surface of the substratum); on rolled oats the height is 42-45 mm.; 
on cornmeal, 25-35 mm.; on starch paste, 20-25 mm.; and on 
grapefruit, 10-19 mm. Dextrose is fermented to some extent but 
tyrosin is not oxidized. In the maltose-peptone-tyrosin solution 
an apricot yellow (Ridgway) submerged mycelium is formed. 
15. MUCOR GRISEO-CYANUS Hagem, Vid.-Selsk. Skr. M.-N. 
Kl. Christiania 19077: 28. f. 9. 1908 
Forming on bread a dense, mouse gray to light mouse gray 
(Ridgway) turf, 0.5-1.5 cm. tall; sporangiophores 8-18 in 
