Feb. i,i 9 2i Another Conidial Sclerospora of Philippine Maize 671 



PHYSIOLOGICAL CHARACTERISTICS 



Several varieties of maize grown in sterile soil and under controlled 

 conditions preventing contamination were infected with spores produced 

 on the living plants of bugang grass (Saccharum spontaneum) and sugar 

 cane brought from Cebu. Parallel inoculations were made also with 

 Sclerospora philippinensis . No difference was apparent either in symp- 

 toms or in the virulence of the resulting infection. Similar experiments 

 with seedlings of cultivated wheat, Setaria, Pennisetum, and several 

 species of wild grasses, including the very common aguingay (Rottboellia 

 exaltata L,.), anias (Andropogon sorghum var. halepense L.)> cogon (Impe- 

 rata cylindracea L.)> and tigbee (Coix lachryma-jobi L.), using the long, 

 narrow conidia of the southern species, were as uniformly unsuccessful 

 as they had been with Sclerospora philippinensis (12). Seedlings of 

 teosinte (Euchlaena luxurians Schrad.) and the wild grasses, Saccharum 

 spontaneum and Miscanthus japonicus (Thunb.) Anders., were success- 

 fully inoculated with both forms. No seeds of sugar cane were available 

 for planting. Had there been, there is little doubt in the mind of the 

 writer that infections in this case also could have been obtained. A 

 more detailed account of these inoculation experiments will be given in 

 a later paper. It should be said here, however, that the effect of the 

 Sclerosporas varied with the different hosts, being most destructive on 

 maize and least so on bugang grass; but the characteristic production of 

 conidiophores took place with uniform regularity at night on all 

 (PI. 78, B). 



A comparative study of material of Sclerospora spontanea on these 

 different hosts showed that the distinguishing morphological character- 

 istics of the fungus had not been altered in any way. Moreover, even 

 after transition from one host to another through several generations, 

 the species remained constant and in no way approached S. philippinensis. 

 In like manner, after inoculating various hosts and passing through 

 several generations, S. philippinensis also was quite unchanged and 

 showed no tendency to approach the long-spored form. 



The writer considers it quite possible that an exact statistical study of 

 large numbers of individuals infected by each of the two fungi would 

 reveal some slight quantitative difference in the area bearing conidia, or 

 in the rate of growth of hyphae through the host, or in some other aspect 

 not at once apparent to an ordinary comparative examination. It 

 should be noted here, however, that there is certainly no noticeable 

 physiologic difference between the two in virulence, range of hosts, or 

 general course of the resulting disease they produce. 



MORPHOLOGICAL CHARACTERISTICS 



Therefore, because the two forms differ morphologically rather than 

 physiologically, they were carefully compared in order to determine 

 whether the points of difference were sufficiently stable and well marked 



