60 
Mycologia 
descriptions and figures given by Coleman indicate that this 
process is of the type which has been described for the two 
preceding species. The oospores at maturity measure 23-38 fx in 
diameter. 
Cross innoculation experiments were carried on with a number 
of plants either known to be hosts of some species of Phytoph- 
tliora, or closely related to some known host. Zoospores were 
used in each instance. Inoculations were made both with P. 
Arecae and P. Faberi. In addition to areca nuts and cacao pods 
the list included for both species of fungi members of the follow- 
ing genera; Cercus, Clarkia, Oenothera, Salpiglossis, Schizanthus 
and Solarium. “ In the case of all the species experimented upon 
successful infection was accomplished with both fungi with the 
exception of Solarium tuberosum. It seems probable that seed- 
lings of this plant also would be susceptible, but they were not 
available. In the case of Solarium melongena and Lycopersicum 
esculentum only seedlings proved susceptible. Inoculations of 
plants above 6 inches high were unsuccessful.” Of three cacao 
pods inoculated one showed Phytophthora mycelium in the tissues, 
but did not produce conidia. 
4. Phytophthora Phaseoli Thaxter 
The first account of the oospores of this species was given by 
Clinton (1906) in a paper which must rank as a classic in the 
literature of this genus as here are first detailed the results of the 
study of a species of Phytophthora in pure culture on agar. The 
oospores occur in nature in the diseased pods and seeds of the 
host. They are smooth, with moderately thick walls, hyaline or 
light-yellowish in color, and 18-26 n in diameter. The antheridia 
are hyaline, ovate to ovoid or irregular shaped bodies, which are 
usually applied to the base of the oogonium, and measure 
8.5-11.5 X 14-17 If appears that “the antheridia are not 
usually entirely differentiated on the thread until after contact 
with the oogonium.” This, by the way, is quite suggestive of 
the description given by Blakeslee of the development of the 
progametes of heterothallic mucors. 
In a later paper (Clinton, 1909) a more extended discussion of 
these phenomena is given. “ In the development of the sexual 
