6^o Journal of Agricultural Research voi. xxiv» No. a 
The parasite on quack grass consequently is to be regarded not as a 
biological race of Helminihosporium gramineum but as an independent 
morphological species. While the ascigerous stage bears a strong resem¬ 
blance to Pyrenophora hromi, as well as to a number of other congeneric 
forms found on graminaceous hosts, it is readily distinguishable at least 
from Pyrenophora teres. On the other hand the conidia which, like 
those of H. teres and H. avenae, show a range in length intermediate 
between the range of this dimension in H. gramineum and H. bromif can 
not possibly be mistaken for the conidia of any of these species because 
of the characteristic contour of the basal segment. 
HHbMINTHOSPORIUM CATBNARIUM, N. SP. 
During the latter part of September, 1920, the writer kept under 
observation a stand of wood reed grass {Cinna arundinacea D.) near 
Brooklyn, N. Y., on the northern coast of Long Island. Although the 
season had not been a dry one, the grass, nevertheless, showed symptoms 
suggesting drought injury. The distal portions of most of the leaves 
had withered completely (PI. 7, A) and, in some instances, the injury 
involved more than half of the blade. Less frequently, the foliar organs 
exhibited longitudinally elongated dry areas or spots within healthy 
green parts. No indication of any discoloration, either at the margins 
of the lesions or in the dried portions, was ever observed. As the disease 
presented many of the characteristics of white blast, quite common on 
sweet com in the tmcking district in the vicinity of New York City, 
some of the affected leaves were collected and examined in the laboratory. 
The microscope revealed an abundance of Helminthosporium fructifica¬ 
tions on the affected leaves, particularly on those parts that had appar¬ 
ently been dead for some time. 
As in other species of Helminthosporium occurring on graminaceous 
hosts possessing foliage with a relatively firm epidermis, the sporophores 
of the fungus on Cinna arundinacea are found to emerge very largely 
from the stomata. (PI. 7, Ea-c.) Beyond being conspicuously thin 
walled, and rather unusually strongly geniculate at the points of attach¬ 
ment of the conidia, they exhibit no especially distinctive features: 
The spores, which are colorless to light yellowish, however, show such 
a large measure of variability in shape and apparent development, that 
the fungus is easily recognized as one of the more aberrant and peculiar 
members of the genus. A considerable proportion of the spores are of 
moderate length, straight and tapering (PI. 7, Ba, d, j), and perhaps could 
not be readily distinguished from those of Helminthosporium dictyoides, 
although the latter eventually become more deeply tinged with yellow. 
Usually only the shorter spores appear both straight and uniformly 
tapering. Generally, those in excess of 80 fx are very perceptibly curved 
or bent in an irregular manner, and, in addition, the diameter of the 
different segments varies to a very considerable extent. The longer 
spores often show a decided median constriction. (PI. 7, Bb, e.) ^ 
Frequently, a secondary spore (PI. 7, Bi) is found attached at the tip 
of a primary one (PI. 7, Bh), being characterized by smaller dimensions 
and, if immature, by the absence of septa. That the formation of 
secondary spores is not an unusual occurrence is indicated by the presence 
of a dark conspicuous scar at the tip of many spores, quite similar to the 
basal hilum and often associated with a peculiar prolongation of the distal 
