672 Journal of Agricultural Research voi.xx,No. 9 



to establish the long-spored form as a species distinct from Sclerospora 

 philippinensis . 



Mycelium. — In morphological characteristics, extent, and relation to 

 the host tissue, the mycelium of the two fungi showed no distinctions 

 sufficiently marked or unvarying to warrant their use as a basis of 

 separation. However, the club-shaped hyphae (conidiophore initials) 

 which grow out through the stomata and develop into conidiophores are 

 different in the two forms, those of the long-spored Sclerospora being 

 markedly longer, more slender, and more irregular. 



Conidiophores. — In general appearance the conidiophores of the two 

 Sclerosporas are noticeably dissimilar, those of the Visayan form being 

 markedly longer, more slender, and more spreadingly branched than 

 those of Sclerospora philippinensis. On analyzing this dissimilarity the 

 details of difference discussed in the following paragraphs are apparent. 



The basal cell of the Visayan Sclerospora is very long (Pi. 79, A, D, 

 E, F, H), strikingly longer than that of Sclerospora philippinensis. The 

 length (140 to 260 yu) is greater not only actually but also relatively, for 

 even in the unusual cases when it is less conspicuously long (PI. 79, G) 

 the basal cell of the Visayan Sclerospora always exceeds or at least equals 

 in length that part of the main axis extending from the terminal septum 

 of the basal cell to the origin of the primary branches. In S. philippi- 

 nensis, the basal cell is always shorter than this part of the main axis. 

 Moreover, the basal cell of the Visayan Sclerospora is much more slender, 

 usually 5 to 8 /t at its narrowest diameter, and much less knobbed or 

 swollen at its base (PI 79, A, D, E, F, H) than is the basal cell of 5. 

 philippinensis. 



The main axis of the Visayan Sclerospora expands more abruptly 

 above the basal cell and then constricts more distinctly (PI. 79, A, D) 

 just below the branches than in Sclerospora philippinensis. The greatest 

 diameter (22 to 32 /z), which usually slightly exceeds that of 5. philip- 

 pinensis, is thus placed, not just below the branches (as in 5. philip- 

 pinensis), but some distance lower (PI. 79, A, D, G, H). 



The branches of the Visayan form generally are less constricted at 

 their point of origin, are of more uniform diameter, and are straighter, 

 less ascending, more spreading, and do not recurve, but stand out from 

 the main axis more stiffly. They are characteristically longer and more 

 slender, but, even if short and crowded, they stand out more stiffly than 

 in Sclerospora philippinensis. Although varying considerably in both 

 species, the number of conidia produced on conidiophores is approxi- 

 mately the same in 5. spontanea and in S. philippinensis. In the former, 

 32 to 48 are commonly borne, although as many as 88 or as few as 12 

 may less frequently occur. 



The sterigmata also are straighter, less recurved, and stand out more 

 stiffly than in Sclerospora philippinensis, and, usually they are longer 

 (about 13 fx). It should be noted, however, that the length varies with 



