2 5 8- 
Journal of Agricultural Research 
Vol. VIII, No. 7 
classes containing the greatest number of individuals in each species. 
Arranged in the order of size, beginning with the largest, we have faberi 9 
jatrophae , parasitica t and nicoiianae. 
Germination or chlamydospores. —Dastur (io) states that the 
“resting” conidia do not require a period of rest before germination and 
that when grown in water germination takes place at the end of 24 
hours. After a careful examination of the figures given by Dastur for 
the “resting” conidia of P. parasitica the writer has no doubt that they 
are identical with those which appeared in his own cultures and which 
are designated chlamydospores. So far, however, all attempts to germi¬ 
nate these either from young cultures or from cultures of considerable 
age have failed, as have also all attempts to germinate the chlamydo- 
Fig. ii. —Graph showing the variation in the diameters of oospores of Pky~ 
topkthora phaseoli , P. arecae, and P. erytkroseptica. 
spores of P . nicoiianae and P. jatrophae. Recently the writer did obtain 
germination of chlamydospores in one of the species by wintering pure 
cultures, but the method of germination appeared to be so radically 
different from that observed by Dastur that it seems advisable to repeat 
the work before the results are presented to the public. 
SEXUAL bodies 
Differences in the morphology of the sexual bodies in the different 
species of Phytophthora are the most constant characters under all 
conditions and therefore the most valuable for use in taxonomic work. 
External conditions, however, such as temperature, chemical nature of 
substrata, length of time a species has been in artificial culture, abun¬ 
dance of food supply, and may other factors have been known to in¬ 
fluence the rapidity of development, as well as the number of sexual 
bodies produced in culture not only in the genus Phytophthora but in 
