7i6 
Journal of Agricultural Research 
Vol. XXIV. No. 8 
is developed 200 /i or more from the point of attachment of the sporophore 
(PI. 25, Bi) and the successive spores are proliferated at relatively long 
intervals, varying usually from 20 to 40 the number of spores produced 
*on a single fructification measuring from 300 to 600 /i is less than might 
be expected (PI. 25, Bh). Although of the same general type as those 
produced in nature, the conidia produced, at least under certain con¬ 
ditions, on tap-water agar are often more slender, measuring up to 140 ju 
in length (PL 25, Ba-g) and varying usually between 15 and 20 fi in 
diameter. A tendency toward curvature also becomes apparent, and 
in some instances quite pronounced. (PI. 25, Bb.) Further details 
concerning the conspicuous variation in the dimensions of hyphae, 
conidiophores and conida resulting from the use of different substrata 
and different temperatures come outside the scope of the present paper. 
Some information concerning the cultural characters of the fungus is 
accessible in Zhavoronkov's (162) paper. 
In the foregoing text the writer has intentionally confined his discussion 
to the parasite associated with the leaf blight of maize, as he has had 
opportunity to examine the fungus in a living condition only on diseased 
foliage collected on Long Island. It is interesting to note that Reinking 
(117) reports the parasite as attacking also the tassels of corn in the 
Philippines. Through the courtesy of Dr. W. H. Weston, jr., the 
writer was able to examine material of diseased corn plants collected on 
these islands, showing an abundance of Helminthosporium fructifica¬ 
tions on both leaves and tassels. The spores scraped from the leaves did 
not appear to differ materially from those produced on these organs in 
the United States. Preparations made from the fructifications on the 
tassel, however, showed conidia which, while of the same color and 
approximate maximum length, were perceptibly inferior in diameter, 
measuring approximately ii to 14 ju in this dimension; more abun¬ 
dantly septate, 12 transverse walls being not uncommon; usually quite 
distinctly curved; and evidently similar to those figured by Reinking 
(117, PL 20f By C). However, as none of these conidia were any 
longer viable, their collapsed condition and incapacity for use in starting 
cultures made it impossible to determine definitely whether the two types 
belong to the same or to different species. The behavior of the leaf- 
blight parasite in culture makes the former alternative appear less im¬ 
probable than a comparison of material collected in the field might 
suggest. If the forms on the leaves and on the tassels should indeed 
prove to be identical, the morphology of Helminthosporium turcicum as 
generally understood would stand in considerable need of revision. 
Helminthosporium turcicum was reported as occurring on Sorghum 
vulgare by Saccardo {128), Butler (jp) also recorded its presence on 
cultivated sorghum in India, Egypt, and China, with the statement 
that it was not very common or destructive on this host. It has been 
reported on sorghum {Andropogon sorghum [L.] Brot.) from Texas by 
Heald and Wolf (55, p, 34); and by these authors, as well as by Atkin¬ 
son (4) on Johnson grass (Sorghum halepense [L.] Pers.) in Texas and 
Alabama, respectively. According to Atkinson, it occurs also on Elymus 
sp. and on Cinna arundinacea L. in Alabama. There is at least a possi¬ 
bility that the fungus which this author found on the latter host may have 
been identical with the one described in this paper as H, catenarium. Cer¬ 
tainly, a critical comparative study of the forms of Helminthosporium 
found on Johnson grass and on various types of sorghum will be necessary 
