114 Journal of A gricultural Research voi. xix, No. 3 



Sclerospora sacchari T. Miy., described by Miyake from Formosa but 

 reported by Lyon (11, 12) also in the Fiji Isalnds and Queensland. 



It has been assumed by Baker (r) and Reinking (17) that the Phil- 

 ippine Sclerospora of maize is identical with Sclerospora maydis (Rac.) 

 But. of India, and this has been generally accepted by other investi- 

 gators. Since no detailed description of the species with critical meas- 

 urements has been published, and the single conidiophore and few spores 

 figured by Reinking are hardly enough on which to base a decision, it 

 seems necessary to corroborate the identification of the fungus. 



A comparison with Sclerospora maydis (Rac.) But. of India and also 

 with the other related species mentioned above is accordingly in order. 

 Such a comparison must necessarily consider the field characters of the 

 disease, such as its effect on the plants attacked, its severity, and its 

 fatality to the various hosts, as well as the specific peculiarities of the 

 causal organism itself. Of these the characteristic structure and dimen- 

 sions of the organism itself are most valuable, since the field characters 

 show, on the one hand, a general similarity in all these fungi and, on 

 the other hand, vary so widely under different conditions as to be con- 

 fusing even in one species. 



The Sclerospora causing the Philippine disease is known in its conidial 

 phases only, and a comparison of this form with other species must be 

 based on this stage. Such a comparison is confronted by many diffi- 

 culties. In the first place, the characters most valuable from the system- 

 atic point of view have been found by the writer to vary greatly under 

 different conditions and at different stages in the development of the 

 Philippine form, and they probably do so in the other forms also. For 

 instance, the very important characters of the size and shape of the 

 conidia and the structure and dimensions of the conidiophores vary 

 greatly at different stages of development and under different conditions. 



The conidia begin as small spherical outgrowths from the sterigmata 

 tips, and in their development become larger and more elongate, passing 

 through ellipsoid (PI. 24, A), oval (PI. 25, A), and even pyriform stages 

 before they eventually assume the elongate ovoid ellipsoid or rounded 

 cylindrical shape of complete maturity (PI. 24, C). They are then 

 separated from the sterigma tip by the septum. 



This characteristic shape is transient, however, for, after they are 

 free from the conidiophores, the spores show an almost immediate 

 imbibition of moisture, which results in a marked increase in size and 

 in a more rotund shape, due to the greater bulging of the side walls. 

 Moreover, the apiculus which marks the point at which the spore was 

 attached to the sterigma is modified, by the swelling of the spore, to a 

 low, rounded curve. 



Since the partially developed spores of various shapes and sizes may 

 be detached from the sterigmata and still retain their contents and 

 germinability, and since marked changes from the shape and size of the 



