BUTLER. 277 



branched, rather slender hypha, often of considerable length (PI. IX, 

 Fig. 4). The subsequent fate of the young plant developed from 

 these spores is not known, the species not having been cultivated 

 and no successful inoculations from conidia having been obtained. 

 In hundreds of germinating spores observed, no case of germina- 

 tion by zoospores was seen. 



Raciborski described a second spore form, which he stated 

 was found only in the young stern and in the leaf-sheaths of young 

 leaves. This he considered to be an oospore. Similar bodies were 

 found in affected plants at Pusa and increased greatly in numbers 

 as the plants decomposed. Fig. 5 of PI. IX, shows the character 

 of these bodies, agreeing in every respect with those described and 

 figured by Raciborski. Further examination showed that they were 

 the resting stage of a species of Protozoa allied to Paramcecium. 

 This result was not unexpected, as the figure given by Raciborski 

 is quite unlike any spore form known to occur in the Peronosfo- 

 racece. A very thorough search was made for true oospores but 

 none were found. 



From the conidial stage, which alone is known with certainty, 

 the fungus is a typical Sclerospora. It is quite unlike any Pero- 

 nosfora. In Berlese's Monograph 1 it is retained in Peronosyora, 

 as the author had not an opportunity of examining any specimens, 

 but he states that, in his opinion, it is rather a Sclerosfora. 

 Pammel 2 has suggested that it is identical with Sclerosjwra grami- 

 nicola (Sacc.) Schroet, the only Sclerospora so far known to possess 

 a conidial stage. But a comparison with this species as it occurs 

 in India on Pennisetum typJioideum, Atidropogon Sorghum and 

 species of Setaria 3 , shows a considerable difference in the size of the 

 conidia, which are much larger on Zea Mays than on any of the 

 others. 



1 Berlese, A. N. Saggio di una monografia delle Peronosporacee. Eivista di Patologia 

 Vegetale, X, 1904, p. 210. 



1 Pammel L. H. Bull. Iowa Geological Survey, I, 1901, p. 188. 

 i>* s See Butler, E. J. Some diseases of Cereals caused by Srlero.tpora graminicola. Mem- 

 Dept. of Agric. in India, Bot, Ser., II, No. 1, 1907, and the paper by Mr. G. S. Kulkarni in the 

 present Memoir. 



