May f 5 ,1923 
Graminicolous Species of Helminthospornim 
719 
external wall, the intermediate segments frequently are exposed and 
sometimes entirely liberated in the course of manipulation, with the 
result that abnormal germination is much more common than in most 
congeneric forms. The germ tubes usually attain a considerable length 
before branching, thus differing in this respect from those of H. cynodontis, 
which frequently proliferate a branch at the very point of origin. The 
hilum in the spores of H, leersii is represented by a scar generally con¬ 
tained within the contour of the basal end, although occasionally it may 
be seen to protrude slightly. In any case, a basal modification like 
that characteristic of the conidia of H. monoceras is never present; nor 
is the hilum a distinctly protruding structure as, for example, in H. 
turcicum. 
When grown on artificial media the fungus, unlike the other species 
similar to Helminthosporium sativum, develops a dense gray aerial 
mycelium, the rate of enlargement being relatively slow. This slow 
development is associated with a peculiarity in manner of growth at 
the margins that is more or less characteristic and has not been observed 
in other species. The imbedded hyphae, although ramifying profusely, 
remain short, thus giving rise to an intricate system of short, rather 
swollen elements of which Plate 26, E, represents merely an incipient 
stage. Here and there a relatively delicate hypha (PI. 26, Ea-b) grows 
out into the air and by curving downward brings its tip in contact with 
the substratum. From the tip numerous short branches are soon 
proliferated which, by continued ramification, again yield an intricate 
system of hyphae. 
HELMINTHOSPORIUM CYNODONTIS MARIGNONI 
In 1909, Marignoni (8g) described as Helminthosporium cynodontis a 
fungus occurring on dry leaves of Cynodon dactylon L. {^Capriola 
dactylon [T.] Kuntze) near Schio in northern Italy. In the brief diag¬ 
nosis given by Saccardo {128, v. 22, p. 1394), the species is thus 
characterized: 
Effusum, atro-olivaceum v. fuligineum; conidiophoris aggregatis, laxis, sim- 
plicibus, parce septatis, tortuosis, 80-150X6-7; conidiis elongatis, utrinque rotun- 
datis plerumque octo-septatis, fuligineis, 60-75X12-14. 
Apparently the fungus has not been reported again, as the subsequent 
literature appears to contain no reference either to Marignoni's binomial, 
or to any species of Helminthosporium occurring on Bermuda grass 
and answering the description given above. The writer nevertheless 
is convinced that the parasite is exceedingly common throughout the 
southeastern section of the United States where the host is everywhere 
present in the fields and on the roadsides as a noxious weed. In Florida, 
near Wauchula, Fort Myers, Tampa, and Gainesville, during the months 
of February, March, and April, 1921, it was found difficult to collect 
specimens of Cynodon dactylon, not bearing fructifications of the fungus 
in considerable abundance. (PI. 27, A.) 
Although the writer has not been able to consult Marignoni’s {89) 
illustrated publication, the American form answers sufficiently well in 
morphological detail to Saccardo's {128) account of Helminthosporium 
cynodontis that, in view of its abundant occurrence on the same host, 
it can at least provisionally be regarded as belonging to this species. 
In the Florida material, the conidiophores (PI. 27, Da-g) which are 
dark brown in color, emerge singly or in pairs from stomata or between 
