1915] COOK & WILSON—ENDOTHIA PARASITICA 353 
who was unable to detect any positive trace of tannin, but found 
a trace of gallic acid not exceeding 0.002 gm. This appears to 
to indicate that the fungus can use the tannin as a food. Pycno- 
spores appeared on the check at the end of the sixth week, on 0.1 
per cent tannin at the end of the seventh, on 1.4 per cent tannin at 
the end of the eighth, and ultimately on the 4 per cent tannin. 
E. parasitica (Chinese strain) grew about the same as the 
American strain except that the growth was 5 days earlier and a 
lighter gray color. Pycnospores appeared during the fifth week on - 
2.4 per cent tannin and ultimately on the entire series. 
It is rather remarkable that the Chinese strain is more tolerant 
to tannin than the American strain, and it raises the question 
whether this resistance is due to origin, age, or modification of 
the fungus since its first introduction into America, or some other 
cause. . 
E. radicalis (European) was more resistant than the American 
strain. Pycnospores were produced on 1.2 per cent tannin after 
8 weeks’ growth. 
E. radicalis (American) gave an abundant growth of aerial 
mycelium, varying in color from yellow in the lower percentage 
of tannin to ashen in the higher. The presence of 0.2 per cent 
tannin was stimulating, but 0.8 per cent retarded the growth. No 
pycnospores were produced. 
_ £. radicalis (Ciinton’s E. gyrosa no. 7677) grew well, but no 
pycnospores were found. The tannin had an inhibiting influence. 
E. radicalis mississippiensis grew well, but apparently was not 
able to use the tannin as food. No pycnospores were produced. 
The two cultures (nos. 2443 and 1196) used were very resistant to 
tannin, the former making the more vigorous growth. 
From this series of cultures it appears that tannin (MERCK) 
affects various species of the genus Endothia quite differently. E. 
parasitica may for a time be retarded in its growth, but subsequently 
it feeds on the tannin, using the entire supply in the cultures tested. 
At the other extreme is E. radicalis mississippiensis, which appears 
to be entirely unaffected by tannin, and does not feed upon this 
substance. The cultures labeled E. radicalis (and CLINTON’s 
E. gyrosa no. 7677) are inhibited by the action of tannin. This is 
