Oct. 15,1925 Leaf spot of Maize Caused by Ophiobolus heterostrophus 723 
fied in A. therryana, illustrated by Berlese (1, v. 2, pi. 167 ); nor Lepto- 
sporella Peng, and Sacc. (13, v. 14, p . 619), would seem to offer any 
species as similar to the maize parasite as 0. camptosporus. In the 
absence of a more appropriate genus to which it could be referred, and 
in order to conserve for the time being its proximity to the latter 
form, the leafspot fungus is tentatively assigned to Ophiobolus. 
Such assignment is not intended to imply close relationship to certain 
species referred to this genus that are frequently mentioned in the 
literature pertaining to the diseases of cereal crops, as, notably, 0. 
cariceti (Berk, and Br.) Sacc., and 0. herpotrichus (Fr.) Sacc. It 
may be superfluous to add that the parasite is undoubtedly different 
from Acerbia maydis Rehm, described from dead remains of maize 
in the Philippines (9), as well as from Leptosphaeria orthogramma 
(B. and C.) Sacc., reported on dead maize culms in Pennsylvania, 
South Carolina (13, v. 2, p. 60), and the Philippines (9), for in respect 
to dimensions of spore, for example, the latter forms are decisively 
inferior to the fungus under consideration. 
As far as the writer is aware, the ascigerous stage of the parasite 
has not been described before. There is scarcely any doubt that the 
conidial stage has been encountered by pathologists, but with the 
possible exception of the somewhat problematical Helminthosporium 
euchlaenae, it has apparently not served as type for any species desig¬ 
nated by a binomial. As has been pointed out, Saccardo evidently 
did not intend to apply to it his binomial H. curvulum. The combi¬ 
nation H. turcicum has long been applied, and seemingly altogether 
correctly, to the fungus causing leaf might of maize and several other 
graminaceous hosts. The excessively brief diagnosis of H. incon¬ 
spicuum applies better to the leaf-blight fungus than to the parasite 
causing leafspot, especially in the details concerning the 3 to 5 sep¬ 
tate condition of the conidia and their diameter of 20 p, although the 
passage t( effused, but so thinly as not to be visible to the naked 
eye” is not readily reconciled with the actual appearance of H. turci¬ 
cum developing luxuriantly on its host in nature. More direct evi¬ 
dence that H. inconspicuum is indeed synonymous with H. turcicum 
is provided by the specimen in the herbarium of the Office of Patho¬ 
logical Collections under the label: 
Ellis. North American Fungi. 45. Helminthosporium inconspicuum C. & E. 
Grev. vol. 6, p. 88. On leaves of Indian corn. 
Which, judging from the date of issuance, 1878, presumably repre¬ 
sents authentic material from approximately the same collection as 
the type specimens. The conidia present in abundance on the very 
extensive affected area were found to be altogether of the broad, 
straight, markedly tapering, relatively sparingly septate type char¬ 
acteristic of.H. turcicum . 
The specific name heterostroplms, descriptive of £he ascospores, is 
suggested for the fungus. 
DIAGNOSIS 
Ophiobolus heterostrophus n. sp. 
Occurring on maize (Zea mays L.), as the cause of a destructive disease mani¬ 
fested by the appearance on the leaves of numerous dead cinnamon-buff or 
purplish areas surrounded by a darker reddish brown margin, and often delicately 
variegated with brownish zonate bands; the lesions longitudinally elongated, 
first elliptical, later long-rectangular, typically limited to a single intervascular 
region, usually 1 to 3 by 5 to 15 mm., often coalescing to form more extensive 
dead portions. 
