686 
Journal of Agricultural Research 
Vol. XXIV. Na 8 
DIAGNOSIS 
Helminthosporium triseptatum, n. sp. 
Fructifications scattered sparsely on withering leaves of Notholcus lanatus (L.) Nash 
(—Holcus lanatus D-)»‘ usually not visible macroscopically or associated with visible 
alterations in the substratum. 
Sporophores arising singly or in pairs, dark olivaceous, 6 to 8 by 200 to 400 u; usu¬ 
ally 6 to li septate, the septa occurring at intervals 18 to 40 ju in length, averaging 
approximately 25 fx; producing first spore approximately 175 jx from base. Prolifer¬ 
ation of spore associated with conspicuous local thickening of peripheral wall resem¬ 
bling ring or band; these thickenings occurring in series, giving upper portions of 
sporophore a more or less moniliform contour. 
Spores dark olivaceous; ellipsoidal or short cylindrical with hemispherical ends, 
sometimes tapering more or less toward basal end; regularly 2 to 3 septate, the septa 
not associated with constrictions in the peripheral wall; the latter unusually thick, 
although somewhat thinner at the distal end, and at the basal end diminishing markedly 
in thickness toward the hilum; the hilum not projecting beyond contour of proximal 
end. Measuring 15 to 21 by 35 to 50 /x; germinating by the production of one or 
two germ tubes at positions adjacent to or in close proximity to hilum. 
Habitat.—Collected during July and August, 1920, near Port Washington, Mineola, 
Valley Stream, RosedaJe. ard Douglaston, N. Y. 
HBDMINTHOSPORIUM VAGANS, N. SP. 
In July, 1919, shortly after the present studies were begun, the 
writer’s attention was called to a leaf spot of Kentucky bluegrass (Poa 
pratensis B.) that seemed to be generally prevalent in the fields and 
lawns about Madison, Wis. Although almost invariably present 
wherever the host was found, the spots were by no means abundant. 
Usually only a small proportion of the leaves were foimd diseased, and 
the majority of these bore evidence of only a single infection. Although 
no spores were found associated with the spots during this season, the 
fungus that was obtained in pure culture from the diseased tissue was 
so similar to other species of Helminthosporium in general growth 
characteristics that observations were resumed the following year. 
The leaf spot reappeared late in May, 1920, quite as generally and 
sparingly as during the preceding season. On June 7, material was col¬ 
lected that showed, moreover, an extension of the trouble to* the leaf 
sheaths, especially toward the base of the plant, the lowermost ones 
being largely involved in diffuse brown discoloration. The condition 
thus brought about appeared not unlike that present in wheat plants 
affected with the disease attributable to Helminthosporium sativum that 
has in recent years become known as ‘‘footrot.” Much more severely 
diseased specimens (PI. 15, A) were collected in Brooklyn, N. Y., on 
August 13, 1920. The foliar lesions, which are of a bluish-black color 
quite intense in the center and fading out gradually at the margins, here 
measured up to 8 mm. in length and 3 mm. in width, although usually 
not exceeding a half of these dimensions. Some of the leaves had with¬ 
ered prematurely, the withering beginning at the tip and proceeding 
toward the base. The bases of the lowermost leaf sheaths surrounding 
the “foot” or “crown” of the plant, were thoroughly permeated with 
a brown pigment. On microscopic examination it was found that the 
withered portions of the leaves, as well as the older, dead, discolored 
sheaths, bore in moderate profusion sporophores with spores typical of 
the genus Helminthosporium. 
In addition to the localities already mentioned, the fungus has been 
collected at many stations in the western half of Long Island, as well as 
