698 
Journal of Agricultural Research 
Vdl. XXIV, No. 8 
are involved. While the Minnesota fungus was not definitely identi¬ 
fied as H. sativum, its similarity to the latter fungus with regard to 
morphological and cultural characters is certainly very close. To be 
sure, L. J. Stakman states that the spores of the wheat parasite, while 
resembling those of H. sativum in shape, “contain few septations and 
are shorter than those described by Pammel, King, and Bakke.*' How¬ 
ever, as the Minnesota fungus appears to have been studied chiefly in 
pure culture, where the spores of H, sativum ordinarily become greatly 
reduced in length and number of septa as compared with those developed 
on the host in the field, on which the original diagnosis undoubtedly was 
based, the difference is very readily explained. 
It may not be superfluous to mention that several species of Helmin- 
thosporium, morphologically altogether different from H, sativum, have 
been reported as occurring on various parts of wheat and rye plants. 
Thus Palm (loi) records the presence on the spikes of this host in Java of a 
relatively innocuous form with small geniculate spores which he identified 
as H. geniculatum T. & E. (r 52), Hennings (59) earlier described as a new 
species, H. tritici, another small-spored but apparently different fungus 
collected by Zimmerman in the region formerly included in German East 
Africa. The African form, described as being very injurious, is evidently 
similar in general habit to H, ravenelii, developing a dense crusty coating 
on the culms, leaves, and heads of the host. Stevens {141) makes men¬ 
tion of a geniculate-spored form evidently different from the one usually 
encountered on diseased wheat in Illinois; while E. J. Stakman records 
the isolation from the same host of strains of Helminthosporium pro¬ 
ducing smaller spores than the species generally found associated with the 
Minnesota disease. A species of Helminthosporium obviously different 
from H. sativum was described from Alabama growing apparently as a 
saprophyte on decaying culms of rye by Atkinson (4) under the name 
of H, tuberosum. The same author also reported H, inconspicuum “ on 
living and languid leaves of Secale cereale,” evidently in a parasitic rela¬ 
tion. It appears at least not improbable that Atkinson, following Peck 
(107), applied the binomial of Cooke and Ellis not to H. iurcicum, but 
to a form morphologically very similar if not altogether identical to 
H, sativum. 
As has been indicated in other connections, when the inflorescence of 
wheat is attacked (PI. 18, D), the kernels often are affected, resulting in 
dark brown, bluish brown, or nearly black discolorations involving more 
or less extensive and irregular patches at the germ end or extending 
along the ventral furrow (PI. 18, Ba-Cb). Hungerford (64) and Water- 
house {156) noted the presence of Helminthosporium fructifications on 
wheat grains. A special type of such pathological effect in which the 
discoloration is relatively intense and limited to the region occupied by 
the embryo (PI. 18, Aa, b) has become known as “black point.'' It is 
characteristic especially of durum wheat, having been reported by Bolley 
(14) in 1910 as being on the increase on this species, and more recently 
made the subject of investigation by Evans {38) as well as by Weniger {158) 
and by Henry {61) . Gree^ouse experiments, now in progress, the results 
of which will be published later, have shown that, compared to healthy 
seeds, badly discolored seeds show a much smaller degree of viability, 
and that ^e plants resulting from them frequently develop lesions 
varying in number and severity. (PI. 18, E.) It may be mentioned 
that ofiier fungi, notably one or several species of Alternaria, also have 
been found associated with discoloration of wheat grains, which, however. 
