May 26, X923 
Graminicolous Species of Helminthosporium 
709 
produces a greyish aerial mycelium, the growth of the parasite on Dis-' 
iichlis spicata, as has been noted previously, has a very dark if not almost 
black appearance. Helminthosporium oryzae, on the other hand, could 
be confused with the fungus under consideration only when cultivated 
on a substratum on which its spores develop dark pigment, as, for 
example, potato dextrose agar. The greater dimensions of the conidio- 
phores and conidia produced by the rice parasite and the position of 
the hilum within the contour of the peripheral spore wall constitute, 
however, features by which the two species can be distinguished in 
spite of some similarity due to the occurrence of subhyaline end seg¬ 
ments in both. Moreover, while the spores of H. oryzae tend to taper 
strongly toward the tip, and to a smaller extent toward the base, those 
of the fungus on Diitichlis spicata show relatively slight tapering toward 
the abruptly rounded apex, while the proximal portion usually tapers 
markedly toward the base. The resemblance between the latter fungus 
and H, rostratum is attributable to similarity in color of the conidia as 
well as to the presence in the spores of both species, of protruding hila, 
and of accentuated proximal and distal septa. The parasite on Dis- 
tichlis spicata, however, is inferior in the dimensions of both sporophores 
and spores and never exhibits the rostrate modification of the apical 
end characteristic of the conidia of H. rostratum. It appears not to have 
been described hitherto. As it is the first member of the genus, as far 
as the writer is aware, to be found occurring as a parasite on a host more 
or less frequently flooded with sea water, the specific name halodes is 
suggested. 
DIAGNOSIS 
Helminthosporium halodes, n. sp. 
Occurring on the foliar organs of Distichlis spicata (b.) Greene, on which it causes 
a disease not usually destructive, manifested by the appearance of poorly defined 
bluish discolored areas especially on the leaf sheath immediately below its jimcture 
with the blade. 
Conidiophores arising from discolored spots after death of host, singly or in groups 
of two; measuring generally 4 to 7 /* in diameter by 60 to 150 in len^; producing 
first spore usually 60 to 100 from base, successive spores at intervals of 5 to 15 
at apices of geniculate irregularities; i to 5 septate, die length of segments highly 
variable, typically 15 to 30 
Conidia as produced under natural conditions straight or curved; measuring 10 to 
14 /i in width by 20 to 105 /i in length; i to 12 septate, the septa in immature spores 
associated with barely perceptible constrictions of the peripheral wall, in mature 
spores not associated with constrictions; brownish yellow, the end segments some¬ 
times lighter in color or subhyaline, and delimited by accentuated septa; tapering 
slightly toward the broadly rounded apex, and more markedly toward the more 
narrowly rounded or somewhat acuminate basal end, which is uniformly distinguished 
by the protruding hilum. Mature spores germinating typic^ly by the production 
of two polar germ tubes, produced at thin-walled regions at tip and immediately 
adjacent to hilum; germination of immature thin-walled conidia often atypical, 
owing to the production of additional germ tubes from one or more intermediate 
segments. 
When cultivated on natural substratum in damp chamber, fructifications similar 
but capable of more extensive development; spores somewhat shorter, usually thicker, 
and tapering more perceptibly toward both ends; dark olivaceous, the end segments 
subhyaline or light fuliginous and set off by accentuated septa. On artificial media 
not rich in organic food material conidiophores arising as lateral branches from pros¬ 
tate hyphae, bearing conidia in moderately dense racemose arrangement at geniculate 
irregularities occurring at short intervals; conidia as on natural substratum dark 
olivaceous provided with subhyaline end segments and with moderately thick 
peripheral wall but shorter, often being nearly ellipsoidal in shape. 
Habitat. —Collected at Douglaston, N. Y., near New York City, in September and 
October, 1920. 
