BOTRYTIS CINEREA. 
1921] 
WEBB—GERMINATION OF SPORES OF CERTAIN FUNGI 301 
Relatively high active acidity in the synthetic culture media 
favors spore germination of Penicillium italicum, but slightly 
alkaline conditions in the sugar beet decoction are equally as 
favorable, if not more so, than acid conditions in the same 
medium. 
In general, a slightly acid or neutral reaction affords most 
perfect germination of the uredospores of Puccinia graminis. 
Germination of the spores of Colletotrichum Gossyp is very 
variable and no definite curve is produced, but an alkaline 
reaction of the medium is most favorable. 
The effects of hydrogen-ion concentration upon the germination 
of these fungous spores in the different culture media are shown 
in tables r-1x, and such relations are graphically presented in 
figs. 2-39. "Tables 1 to 1x follow. 
TABLE I 
AVERAGE PERCENTAGES OF SPORE GERMINATION IN 
CE worn 200 CULTURE MEDIA AT DIFFERENT TEMPERATURES 
AT VARIOUS HYDROGEN-ION CONCENTRATIONS 
Hydrogen-ion concentration, Px Media 
Temp. |Hrs. 
1.6| 2.0, 2.5| 3.0} 3.6| 5.0| 6.2) 6.9| 7.7| 8.8| 9.6/10.0+ 
+e ONEEN | EROS e 
6 | 0.0| 0.029.4| 63.841.9| 26.9]14.4| 1.9| 0.0 0.0; 0.0 
23° C.| 20 | 9.5/28.0,83.5, 93. 1/66.9| 37.521.9/24.5| 0.0) 0.0) 0.0) 0.0 
o 
6 | 0.0 38.3| 65.1/75.2| 33.0/110.3| 1.5| 0.0) 0.0, 0.0) 0.0 8 
27? C.| 20 | 0.0/21.0/72.3| 93.6/89.5| 48.1/24.0/15.6| 0.0| 0.0) 0.0) 0.0 s 
a 
6 | 0.0; 0.0 0.0) 17.0) 6.0, 4.2, 1.0} 0.0} 0.0) 0.0, 0.0; 0.0 
30° C.| 20 | 0.0) 0.0/54.9| 79.1/68.4| 52.1|16.3| 7.6] 0.0} 0.0} 0.0 0.0 
| 1.2| 1.8 6) 3 t 3.7 5.0 5.9 6.6 7.0| 7.9 .4| 9.4 
22° C. 6 | 0.0| 0.0,88.0 93.591 0| 44.5/66.0114.522.0| 0.0; 0.0) 0.0, 0.0 
20 | 0.0| 0.091 100.096 5| 50.4/58.3/39.5/25.8| 2.6) 1.2} 0.0) 0.0 P 
Q 
2, 
6 | 0.0) 0.0) 6.5) 89.090.0| 70.5,58.0| 5.0) 4.0} 0.0; 0.0, 0.0) 0.0 E: 
27? C.| 20 | 0.0| 0.0/774.0| 96.7,96.8 ibd uf s 112.270.0.0.0 0.00.0 © 
: 1 0.0 T T 0.0 0. 0.0) 0 o 0.0; 0.0| 0 o 0 o 0.0) 0.0 
30? C.| 20 0.0 0.0} 0.0| 36.3/771.3| 47.7118.4114.5| 1.0) 0.0) 0.0) 0.0| 0.0 
