Oct. 15,1925 Leaf spot of Maize Gaused by OpMobolus TieterostropTms 707 
8 to 10 /x in diameter; while 200 spores varied from 36 to 112 /x in 
length, and from 10 to 18 /x in diameter. As the sporophores and 
spores of H, turcicum do not differ greatly in length from those of the 
leafspot fungus, the figures given for this dimension might be nearly 
equally acceptable for either species. On the other hand, the diameter 
of these structures differs considerably between the two parasites. 
The range given for the diameter of conidiophores would seem much 
more acceptable for H. turcicum than for the fungus causing leafspot; 
while the range in spore diameter is certainly characteristic of the 
leafspot parasite and not at all characteristic of H. turcicum. Mar¬ 
quez 7 statement that “the conidia are wider at the middle and 
gradually taper toward the two ends; they are septate, and are 
crescent-shaped 77 would seem to lend additional support to the 
assumption that he dealt with the leafspot fungus. 
The inferences drawn from the publications of Reinking and of 
Marquez are altogether in harmony with direct evidence provided 
by examination of various lots of diseased material originating in the 
Philippines, mostly in the region in which those writers made their 
observations. The specimens of affected maize leaves collected near 
Los Banos in November, 1921, to which reference has already been 
made, exhibited a number of lesions typical of leaf blight, some of 
them 15 and 20 cm. long, with an abundance of fructifications in the 
center of the dead areas. The spores obtained from such areas 
differed in no wise from the conidia associated with leaf blight en¬ 
countered in the Middle Atlantic States—broad, mostly straight, 
tapering markedly toward the basal end, provided with a protruding 
hilum, and with septa not exceeding eight in number. In addition, 
the leaves bore a much larger number of spots altogether similar to 
those present on the Florida material—similar in color and zonation 
as well as in being delimited laterally, when well developed, by the 
larger veins, which as the specimens represented more mature foliage, 
were spaced at intervals of approximately 3.0 mm. Preparations of 
the discolored areas revealed a relatively sparse development of conid¬ 
iophores and conidia, which after treatment with chloral hydrate 
showed, except for the degenerate contents and swollen membranes 
characteristic of dead structures, complete similarity in morpho¬ 
logical detail to the Florida fungus as collected in the field. The 
specific identity of the two forms was established beyond any question 
when some of the Philippine material was incubated in damp cham¬ 
bers. Some of the spots gave rise to an outgrowth of sporophoric 
filaments bearing conidia differing in no particular—size, s^ptation, 
coloration, curvature, or basal modification—from those resulting from 
the incubation of Florida material under like conditions. 
The fresh conidia were utilized in making a number of single-spore 
cultures, which again were completely like those of the Florida para¬ 
site. Complete similarity was found to obtain also in regard to 
perithecia, asci, and ascospores, as well as to the conidial fructifica¬ 
tions developed in cultures derived from ascospores or pieces of imma¬ 
ture perithecium. The fact that the material collected in November, 
1921, gave rise to fresh fructifications when placed in a damp chamber 
as late as October, 1924, is indicative of a considerable measure of 
longevity in the mycelium of the fungus found within the tissues of 
the diseased leaves, since the old conidiophores and conidia could in 
no instance be made to germinate. 
