Feb. i,i 9 2i Another Conidial Sclerospora of Philippine Maize 679 



Material of the type will be found in the pathologic collections of 

 the Bureau of Plant Industry, Washington, D. C, and in the herbarium of 

 the Bureau of Science, Manila, P. I. 



DISCUSSION 



RELATIONSHIP 



The two Sclerosporas, Sclerospora spontanea and 5. philippinensis, are 

 undoubtedly closely allied to each other. It is even possible that future 

 investigation will bring to light forms intermediate between them. Such 

 may be the downy mildew on maize seen by Prof. Reinking in the Cota- 

 bato Valley and by Gov. Coverston in Lanao Province, both of which 

 places are in the southern Island of Mindanao. On the other hand, 

 the Mindanao form may be as different from 5. spontanea and 5. philip- 

 pinensis as these have proved to be from each other. The writer feels 

 confident that on further search additional Sclerosporas will be encoun- 

 tered in the Philippines both on cultivated hosts and on wild grasses. 



The relationship of the Philippine downy mildew Sclerospora to the 

 similar forms described on maize and related crops from other oriental 

 countries has been discussed in connection with Sclerospora philippi- 

 nensis (12). Unfortunately the matter can not be settled finally with 

 the data available. As the writer's discovery that suitable material 

 can be secured only at night is very recent, previous publications present 

 measurements and other data inadequate for comparison with living 

 material. In so far as one can judge, however, 5. spontanea, on account 

 of its longer, more slender spores, is even more sharply distinguished 

 than is 5. philippinensis from the Javan species, S. javanica Palm (io), 

 from the species of British India, 5. maydis (Rac.) Butl. (1), and from 

 the normal, short spored type of the Formosan species, i>. sacchari 

 Miyake (9). It is of interest to note, however, that in the greater length 

 of its conidia, the very character wherein it differs so distinctly from 

 these other oriental species, 5. spontanea tends to resemble the two 

 abnormally long-spored forms recorded by Japanese investigators. In 

 his account of 5. graminicola, Ideta (8, p. 143-145), in addition to conidia 

 of the size characteristic of the species, mentions a class of conidia having 

 the— 

 shape of a long ellipse, 38.4 to 57.6 n long by 19.2 to 24 /x wide. 



Also, Miyake (9), in his account of 5. sacchari, describes conidia not only 

 of the usual shape and size, but also of an unusual type — 



long ovate, 49 to 54 /x by 19 to 23 ju. 



The descriptions and drawings of both these long types of conidia 

 remind one of the spores of 5. spontanea, even though the latter are 

 characteristically more slender. It is very probable that the occur- 

 rence of these long conidial types in Japan and in Formosa indicates the 



