720 
Journal of Agricultural Research 
Vol. XXIV, No. 8 
epidermal cells, and thus show less tendency to occur in groups than 
those of most congeneric species. They measure from 50 to 150 ju in 
length, and from 4 to 6 ju, typically 5 ju, in diameter, the range in length 
agreeing well with that given in Saccardo's diagnosis. On the other 
hand, the measure of agreement in diameter of sporophore is somewhat 
less satisfactory than might be expected in a dimension exhibiting 
relatively little variability. The number of septa in the conidiophores 
range from 2 to 5, depending largely on the length of these structures. 
The conidia (PI. 27, Ba-u) of the American, form, measuring ii to 14 
by 27 to 80 jXy are straight or more frequently somewhat curved; widest 
near the middle from which they taper slightly toward the abruptly 
rounded ends; subhyaline to fuliginous in color, never brown or dark 
olivaceous; and 3 to 9 septate, the septa not being associated with 
constrictions in the relatively thin peripheral wall. On being mounted 
in water they germinate promptly by the production of two polar germ 
tubes approximately 3 jx in thickness, one from the apex and the other 
in immediate proximity to the hilum that can be distinguished within 
the rounded contour of the basal cell. (PI. 27, Ca-i.) Very frequently 
a lateral branch is produced near the origin of the germ tube, thus often 
simulating the appearance of two germ tubes. (PI. 27, Cc, e.) The 
spores are obviously of the same type as those of Helminthosporium 
sativum, from which they differ markedly however, in size, thickness of 
peripheral wall, and depth of coloration. They are inferior also to those 
of H, leersii in length and number of septa; and to those of H. micropus 
in width, besides lacking altogether the peculiar modification of the 
basal segment characteristic of the latter species. The fungus grows on 
artificial media, producing a moderate quantity of light gray, fluffy 
mycelium, especially at some distance from the point at which the 
inoculum was planted. It has not been observed to sporulate in culture 
on media ordinarily employed in laboratories, although the production 
of spores could probably be induced by providing more suitable substrata. 
It may be mentioned that while the fructifications of Helminthosporium 
cynodontis are found occurring most abundantly on moribund or withered 
leaves of Cynodon dactylon, the fungus also has been collected repeatedly 
on Eleusine indica in Florida in the spring of 1921. In the vicinity of 
Washington, where the parasite was present in moderate quantity on 
Bermuda grass from August to October, 1921, it was not found on goose 
grass, indicating that the latter host is somewhat less favorable for its 
development. A form morphologically very similar and probably identi¬ 
cal has been found to occur very consistently on withered leaves of 
Muhlenbergia mexicana (L.) Trin. collected in the vicinity of New York 
City and Washington, D. C. Although further investigation of the host 
range is necessary, indications are not wanting that the species will 
eventually be found on more than a few members of the Gramineae. 
HELMINTHOSPORIUM MICROPUS, N. SP. 
About the middle of April, 1921, the writer observed a peculiar disease , 
affecting young plants belonging to a species of Paspalum, provisionally * 
identified as Paspalum hoscianum Fliigge, that was found common in 
moist, poorly cultivated fields near Wauchula, Fla. The trouble occurred 
on seedlings from 3 to 6 inches in height, first becoming apparent on the 
tender young foliage as a localized wilting. (PI. 28, A.) Portions of 
foliar tissue from a few millimeters to several centimeters in length, and 
