672 • 
Journal of Agricultural Research 
Vol. XXIV, No.« 
DIAGNOSIS 
Helminthosporiiim catenarium, n. sp. 
Attacking the foliage of Cinna arundinacea, D., where it causes the premature 
death of large areas of tissue, the tip and margin being usually most commonly affected. 
Sporophores brown or olivaceous; emerging usually from the stomata, singly or 
in groups of 2; measuring 5 to 8 by 60 to 200 /x; producing the first spore at a distance 
of 25 to 60 M from base, and successive spores at intervals of 15 to 30 fi, the point of 
attachment marked by scars at the apices of pronounced geniculations. 
Spores I to lo-septate, the septa sometimes associated with slight constrictions or 
irregularities in the contour of the thin peripheral wall; subhyaline to light yellowish, 
14 to 18 by 30 to 200 /i, measured at their maximum diameter; the shorter ones 
usually straight, widest at the basal or second segment, tapering uniformly to approxi¬ 
mately half the maximum diameter at tip; the longer ones often perceptibly crooked, 
irregular in diameter, frequently showing both a basal hilum and an apical scar, the 
ajjical scar marking the attachment of a secondary spore, and usually associated 
with a peculiar modification of the distal portion of the terminal segment, consisting 
- in the prolongation of the latter at a uniform diameter representing the minimum 
width of the spore. Secondary spores or spores of a higher order of the same diameter, 
but usually considerably shorter, less frequently septate, or continuous. Both 
types germinating normally by production of i or 2 lateral germ tubes from basal 
segment, and a single lateral or oblique tube from terminal segment. Contour of 
basal end hemi-ellipsoidal, of distal end hemispherical; hilum and apical scar not 
protruding. 
In pure culture on potato glucose agar, aerial mycelium white or dirty yellowish, 
present as dense erect tufts 2 to 5 mm. high at point of inoculation and as small flecks 
scattered sparsely over the surface; in eifiier case consisting of sterile hyphae and an 
increasing number of conidial fructifications; the latter arising on the expanded termi¬ 
nations of hyphae not otherwise much modified, and consisting of a series of succes¬ 
sively proliferated spores that may be either sessile or separated by intercalary, nar¬ 
rower sporophoric segments. The fructification frequently branching, as a result of the 
proliferation of lateral or oblique sporophoric processes from the basal or terminal 
segment of individual spores; and, less typically, sometimes consisting of miscel¬ 
laneous jjrocesses of segments varying from 6 to 18 /x in thickness, and disarticulating 
at constricted septa -marked by the presence of scars or hyla. 
Habitat. —Parasitic on Cinna arundinacea L. collected at Douglaston, N. Y., 
September, 1920.’^ 
HElvMINTHOSPORIUM BROMIDIEDICKK—PYRENOPHORA BROMI (DIED.) 
Helminthosporium gramineum Rab. f. sp. bromi Diedicke olim 1902, in Centbl. Bakt. 
[etc.] Abt. 2, Bd. 9, p. 317-329* * 
Pleospora bromi Died 1903, in Centbl. Bakt. [etc.] Abt. 2, Bd. ii, p. 52-59. 
Pleospora trichostoma (Fr.) Wint. f. sp. bromi Noack 1905, in Ztschr. Pflanzenkr. v. 
is> p* 193-205. 
The occurrence in Germany of a species of Helminthosporium parasitic 
on Bromus as per Murr. was recorded by Diedicke (28) in 1902. Krieger ® 
later collected and distributed the same fungus on the leaves of Bromus 
inermis Leyss. It undoubtedly is on the latter host that the parasite 
is found most commonly in the United States, observations made by 
the writer in the vicinity of Madison, Wis., during the spring of 1920, 
pointing toward its general prevalence on this widely distributed host. 
Diedicke described llie disease symptoms occasioned by the fungus so 
adequately that little can be added except in the way of corroboration. 
Helminthosporium bromi is probably one of the earliest of all parasites 
affecting the grasses of our northern latitudes, to appear in spring, as 
^ Type specimens of all species described in this paper as new have been deposited in the following 
herbaria; Ofiice of Pathological Collections, Bureau of Plant Industry, United States Department oi 
Agriculture, Washington, D. C.; Cryptogamic Herbarium, Harvard University, Cambridge, Ma^.; 
herbarium. New York Botanical Garden, New York City; herbarium, Department of Botany, University 
of Wisconsin, Madison, Wis. 
* Krieger, W. fungi saxonici. No. 1941 Helminthosporium bromi Died, [exsiccati]. 1903, 1905. 
