274 BOTANICAL GAZETTE [NOVEMBER 
this region (figs. 34, 35). As it is possible to find nuts seemingly 
free from any other organism, the black crust fungus is easily 
isolated. Small pieces of tissue taken aseptically from immediately 
below the crust on direct plating gave pure cultures. 
MorpHo.tocy.—The mycelium on cornmeal agar is of two 
kinds, that made up of cells which are longer than wide, and that 
with cells either nearly globular or wider than they are long (figs. 18, 
19). The long-celled type predominates, both in the aerial and 
the submerged mycelium, except near pycnidia, where the shorter 
cells are most in evidence. The long cells are 14-32 u in length 
by 3.5-14 in width, the short ones measuring 10-18 yp in diameter. 
Both types are thick-walled and black when mature, and both 
have granular contents (figs. 19, 20). In autoclaved rice and in 
the black crust of diseased nuts the hyphal cell is transformed 
until the hyphae suggest chains of conidia (figs. 14, 20). These 
cells are black, 1o-15X5-8y in size, and contain one or two 
guttulae. They readily break away from the hyphae and function 
as spores. 
Pycnidia are produced sparingly, and only along the border of a 
thallus where it comes in contact with another thallus, either of the 
same or of some other species. No pycnidia were found on dis- 
eased nuts or on any of the cultures except those on cornmeal agar 
plates. They are black, smooth, globose-conical, beaked, and 
150-350indiameter. The beak is 100-250 yp in length (figs. 2, 21). 
The spores are borne at the base of the pycnidial cavity on 
short, hyaline, often septate conidiophores which are interspersed 
with narrow strap-shaped, hyaline, continuous paraphyses that 
are from one to six times as long as the conidiophores, the conidio- 
phores being 5-14 4 in length by 3-5 uw in width (fig. 13). The 
spores are at first hyaline, unicellular, 26-36 X 14-20 u in size and 
irregular in shape, but with maturity they become sooty black, 
striated, uniseptate, regular in shape and uniform in size, being 
28 X14 p (fig. 15). 
CULTURE CHARACTERS.—On cornmeal agar plates the fungus 
grows at the rate of o.5-o.7 mm. per day at room temperature. 
The thallus is at first milk white, and the margin of it remains 
uncolored so long as it is increasing in size. After five or six days 
