644 
Journal of Agricultural Research 
Vol. XXrV, No. 8 
Sacc. {128, y. 4, p. 403) and Napicladium Thiim. {130) are distinguished 
from Helminthosporium, the former in possessing relatively short spores, 
the latter in having spores tapering toward the apex. Naturally, these 
distinctions are based on no fundamental differences, and may readily 
be supposed to have been advanced primarily to serve in dividing in 
some way a large group of organisms into a number of smaller groups. 
As it is not always possible to determine definitely whether the spores of 
a certain species are in the main to be regarded as longish, or short, or 
tapering, the advantage accruing from erection of these genera on 
artificial distinction has been at least partly counteracted by the con¬ 
fusion occasioned by different writers assigning the same form to different 
genera. Indeed, certain of the forms included in the present paper have 
been assigned by some writers to one or the other of the genera allied 
to Helminthosporium, and a few other forms might perhaps be thus 
assigned with equal cogency. . 
The imperfect fructifications characteristic of the genus Helmintho¬ 
sporium consist of sporophores emerging from the substratum singly or 
in clusters, or more rarely arising as a dense, velvety layer. After 
attaining a certain length and becoming usually one-to-several-septate, 
depending somewhat on the species, a spore is developed at the tip. 
After the latter has reached a certain degree of maturity the sporophore 
continues to grow near the point of attachment of the first, pushing aside 
the first spore, and producing another spore a little farther on. A number 
of spores are thus produced, which, with the exception of the last one, 
usually fall off or are blown off in nature, their places of attachment 
being marked by a series of geniculations bearing a dark scar at the apices. 
In most foliicolous species, the sporophores as collected in the field show 
branching in only relatively infrequent instances, although a few forms 
exhibit a more readily demonstrable tendency toward ramification. 
In H. ravenelii branching of the sporophore is, however, very abundant 
and accounts in a measure for the dense, velvety texture of the crust. 
Length, width, color, frequence of septation, and general habit of the 
sporophore, while of considerable value in the diagnosis of some species 
and consequently always to be given consideration in specific descrip¬ 
tions, in general leave much to be desired in distinctiveness. 
The mode of emergence from the epidermis of the host is usually not 
especially characteristic. In the case of those grasses having small 
leaves provided with a relatively delicate epidermis emergence usually 
takes place in an altogether miscellaneous manner, either from the 
stomata or between epidermal cells. In the case of those grasses of 
which the epidermis is mechanically somewhat stronger, as in barley or 
barnyard grass, the sporophores, especially in the beginning before the 
leaf tissue becomes distorted by shnveling, show a tendency to emerge 
from the stomata, although emergence between epidermal cells is never 
uncommon. The only instance observed by the writer where the sporo¬ 
phores appear to be entirely confined to the stomata is that of Helmittr 
thosporium turcicum on com leaves, the localization here being readily 
attributable to the character of the epidermis, which in this host is of 
unusual mechanical strength, the stomata on the other hand being large 
and uniformly distributed. Sporophores may appear singly, or in clus¬ 
ters ranging in numbers from 2 to 5, 6, or even 7. Small clusters usually 
are proliferated nearly simultaneously. However, where the number 
runs up to half a dozen, some of the sporophores are usually younger. 
