Wilson: North American Peronosporales 
57 
tinguishable from that of the castor bean attacked the sesame 
seedlings. Reciprocal inoculations proved the two fungi to be 
identical. 
This very interesting fungus is certainly a species of Phytopli- 
thora, yet its conidial germination, the formation of globose, inter- 
calary conidia, and its ability to live for a time in the soil all 
point to close relationship to Pythium. 
2. Phytophthora Colocasiae Racib. 
This species was first described from Java on Colocasia escu- 
lenta (C. antiquorum Schott.) where it is widespread, but not con- 
sidered of great economic importance. It has since been found 
in Formosa and over a wide range of teritory in India, where it 
causes sufficient damage to attract the attention of the workers at 
Pusa. The results of the studies of Butler and Kulkarni (1913) 
are highly suggestive of the possible extension of our knowledge 
of other species of the genus. 
On account of the falling of the conidia with a portion of the 
conidiophore attached after the manner of the pedicel cell of 
Basidiophora and Kawakamia the species was transferred by 
Sawada ( 191 1 ) to the later genus as K. Colocasiae. The fungus 
is certainly a Phytophthora, while Kazvakamia is more closely 
related to Basidiophora. 
Originally described as a leaf parasite, the investigations of 
Butler and Kulkarni show its activities to be much more widely 
extended. Not only are the leaf-blades and petioles, and even the 
inflorescence attacked, but “ the parasite commonly reaches the 
corm and sets up a dry rot during storage,” while badly infected 
plants may even fail to develop corms. This activity is quite 
suggestive of the tuber-rotting of the potato by P. infestans. In 
this connection it might be remarked that it is not at all im- 
possible that the tuber-rot of Colocasia in which was ascribed by 
Massee to the activities of his Peronospora trichomata was in 
reality due to the attacks of Phytophthora. 
Detailed studies were made of the fungus both on the host and 
in pure cultures. The hyphae are quite large (4-9 in diameter), 
with numerous simple, filamentose haustoria. On the aerial parts 
of the host the fungus is strictly intercellular, except for the 
