May 36,1933 
Graminicolous Species of Helminthosporium 
651 
The conidial form that von Post observed developing on the brown 
areas of affected leaves he identified with Helminthosporium gramineum 
Rab. as defined and distributed by Eriksson. 
Rostrup {i23)j in 1888, described a disease characterized by symptoms 
and development similar to those described by von Post, which had been 
doing considerable damage in certain sections of Denmark, and which he 
attributed to a new species of Napicladium, N, hordei. 
In 1892, Pammel {102) reported a destructive disease of barley from 
Iowa, which obviously was identical with that described by von Post, 
being evidenced long before heading time by the presence on all the 
leaves of affected individual stools, of pale yellow streaks extending 
from base to tip, premature death, and subsequent tearing of the foliage 
into shreds. Pammel identified his fungus with the one distributed by 
Eriksson as Helminthosporium gramineum Rab. 
Publications by Ritzema Bos {120) and Frank {43) are evidence that 
the same type of malady appeared and caused losses during the next 
few years in Holland and in Germany. However, Ritzema Bos’ figures 
of the foliar lesions as well as of the 8-septate spore, and the description 
of the symptoms in Frank’s earlier account {42) leave a suspicion that, 
like Eriksson, these authors were dealing not with stripe alone, but also 
with net blotch, and failed to distinguish between the two diseases and 
causal organisms. 
Rostrup {123) appears to have been the first investigator to recognize 
that barley was affected by two different diseases caused by two distinct 
related fungi. However, as he associated Rabenhorst’s binomial with 
the cause of the less destructive “leaf spot disease” {bladpletsyge) instead 
of with the “stripe disease” {strihesyge), and attributed the latter to a 
different although related genus of fungi, the prevailing taxonomic con¬ 
fusion was not immediately settled. Indeed, it was not until the appear¬ 
ance of Ravn’s detailed papers (115, 116) that the ambiguity, which 
Eriksson’s publications had originally introduced, was disposed of 
effectively. Ravn assigned the parasite causing stripe to Helmin¬ 
thosporium gramineum Rab., reduced Napicladium hordei Rostrup to a 
synonym, and distinguished the fungus very clearly, with regard to 
morphology and pathogenicity, from the congeneric forms causing net 
blotch of barley and leaf spot of oats. 
While Ravn’s papers (ii5, 116) thus left no further occasion for con¬ 
fusing Helminthosporium gramineum with //. teres, it did nothing to 
distinguish it from H, sativum, a species later described from the United 
States, but the occurrence of which as a third congeneric form parasitic 
on barley has not been recognized in Europe. As will be pointed out in 
another connection, the European literature is not devoid of ambiguous 
accounts, of which Massee’s treatment (po) of barley leaf blight may be 
taken as an example, indicating that H. sativum is certainly not altogether 
absent, but usually is mistakenly recognized as H. gramineum. And a 
similar condition obtains in the writings of investigators in America and 
other countries. 
Yet after allowances for erroneous diagnoses are made, stripe remains 
one of the most important and vddespread diseases of barley. In Europe 
it has been reported not only from Sweden (rxj), Denmark {115), Ger¬ 
many {42), and Holland {120), but also from England by Prain and 
Percival {112) and by Biffen (i 3), from Ireland by Johnson (72), and from 
Russia by Jachewski {66), According to the records of the Plant Disease 
Svuvey, it is found in most of the States of the Union, apparently wherever 
