VARIATIONS IN PLEURAGE CURVICOLLA (WINT.) KUNTZE 407 
Variation in the Number of Spores 
Perhaps the first and most striking thing observed when a crushed 
perithecium of this organism is examined microscopically is the large num- 
ber of spores in the asci. This species as originally described by Winter^ 
contains 128 spores in an ascus. Griffiths^ in his monograph of the North 
American Sordariaceae states that all but one of his strains, which had 
128, had 256 spores in the ascus. He says that he did not count all the 
spores but counted enough to convince him that there were more than 128, 
and since another nuclear division would make 256, he assumed that there 
probably were that number in an ascus. Owing to the great number of 
spores and to the tenacity with which they cling together, it is impossible to 
see all the spores, but in the strain under discussion the writer has been 
able to count 375 in one ascus and 350 in another and in several other in- 
stances 300 or more. Counts were made by mounting a single mature 
ascus on a microscopic slide in a drop of water under a cover slip, and crush- 
ing the spores out by pressing on the cover. Nevertheless, it has never 
been possible to obtain a distribution of the spores which would permit an 
exact count. In many cases a portion of the spores were counted and the 
remainder estimated. It was decided finally that there must be in the 
neighborhood of 500 spores in each ascus and probably 512, which would 
be the number resulting from another nuclear division after that suggested 
by Griffiths, or from nine mitotic divisions in all. 
It would seem then that Pleurage curvicolla may have 128, 256, or 512 
spores in the ascus. The number seems to be constant for the strain under 
all conditions so far as present observations extend. 
Spore Size 
Perhaps the most reliable characters used in the determination of a 
species are the spore size, shape, markings, etc. A large number of spores 
taken from mature perithecia growing on various media have been measured, 
and the results are tabulated below. Only the dark, opaque spores were 
considered mature and were measured. 
Table i 
Medium 
Age of Cul- 
ture 
Receptacle in which 
Grown 
Spore Size Max. and Min. Limits. 
Irish potato agar 
30 days 
Petri dish 
II-I3 X 15-19 n 
Irish potato agar 
16 days 
Petri dish 
10-13 X 13-15 M 
String bean agar 
14 days 
Petri dish 
10-13 X 13-15 M 
Corn meal agar 
15 days 
Petri dish 
9.5-II.25 X 13-17 fX 
Corn meal 
41 days 
Erlenmeyer flask 
9-1 1 X 13-15 M 
Melilotus stem 
33 days 
Test tube 
9-13 X 13-19 M 
9-13 X 13-19 iJL, max. and min. 
limits. 
2 Winter, G. Hedwigia 10: 161. 1871. 
3 Griffiths, D. Mem. Torrey Club 11: 1-134. 1901. 
