310 
Mycologia 
the writer that in a strain of S. ferax which he cultivated, he was 
able to get from i to 95 per cent, of antheridial oogonia, depend- 
ing on the medium used. 
In 1911 I collected at Heidelberg, Germany, a species which I 
determined as S. ferax because I failed to find any antheridia on 
fly cultures. From time to time I secured antheridia when the 
fungus was grown in artificial media but not until 1913, having 
carried the culture to Ann Arbor, did I note antheridia on a fly 
culture. This led me to question the identification and to re- 
examine the original material on fly, this having been preserved 
in alcohol ; not one antheridium was to be found. 
During that winter I collected a number of cultures from the 
various dishes of algae kept in the botanical laboratories at the 
University of Michigan. Each form was isolated by making a 
single spore culture and a number of these could be referred only 
to F. ferax although in no case were antheridia entirely wanting. 
To test the matter of the production of antheridia, fly cultures 
were prepared and kept in a cool room, and the odgonia having 
antheridia were counted by examining the culture in the dish 
under a 16 mm. objective and a 12 X eyepiece. With this com- 
bination the antheridia can be plainly seen and the culture does 
not need to be disturbed. The number of oogonia counted and 
the number with antheridia are recorded in the following table. 
Culture 
No. 
Date 
Temperature 
No. Counted 
No. with 
Antheridia 
25 
Nov. 19, 1913 
Cool (i2°-i5° C.) 
200 
II 
2 IF 
“ 20, “ 
200 
19 
2 IF 
«( «« <■ 
Room Temp. (22°-l-C.) 
200 
0 
28 
" 19. “ 
Cool 
100 
4 
28 
“ «♦ *4 
Room Temp. 
Many, not counted 
0 
17 
( 5 . mixta) 
“ “ 
44 44 44 
90% at least 
33 
Nov. 20, 1913 
Cool 
100 
I 
34 
125 
3 
35 
“ 23, ■■ 
100 
14 
35 
.. 
100 
II 
35 
“ 
100 
13 
