Mycologisches Centralblatt, Bd. II, Heft 1. 
Ausgegeben am 10. Januar 1913. 
On two species of Heterosporium particularly 
Heterosporium echinulatum. 
By 
W. J. DOWS ON, B. A., Cambridge. 
(With 3 Photomicrographs and 52 textfigures.) 
I. 
In October 1911 Prof. Klebahn brought to me some diseased 
leaves of Beta vulgaris taken from the experimental fields belonging to 
the Landherrenschaften at Hamburg. The outward appearance of the 
disease took the form of dark brown spots, varying from 5 cm to 
1 cm in diameter, which were either isolated or confluent, in which latter 
case the disease areas were large and irregularly shaped and dark brown 
to black in colour. The infected leaves were always the lower-most ones. 
From these diseased areas several members of the Fungi imperfecti were 
isolated such as Macrosporium- sp., Alternaria- sp., Hormodendr tm-sp., 
Epicoccum, and a species of Heterosporium. In the disease areas were 
also found small rounded bodies which appeared to be young perithecia; 
they were unripe and were composed of a pseudoparenchymatous tissue. 
The disease seems to be that described hy Frank 1 ) as „die Schwärze 
oder Bräune der Runkelrübenblätter“ which according to him is 
caused by Pleospora putrefaciens. Frank gives Sporidesmium and Clado- 
sporium as additional spore-forms of this Pleospora; but Brefeld 2 ) has 
shown that Alternaria is the real conidial form. The presence of Alter¬ 
naria and the young perithecia-like bodies taken together with the general 
appearance of the disease seemed to indicate that the disease here under 
consideration was the same as that described by Frank, although he 
confused the conidial forms. The other fungi were probably growing 
saprophytically upon the disease areas. Prof. Klebahn suggested that 
some of these forms might be cultured and compared with other nearly 
related forms, both as to their growth upon nutrient media and upon the 
Beta plant itself. For this purpose he placed at my disposal his spirit 
material of Heterosporium Syringae which he had found some years ago 
as parasitic upon the lilac. Another easily obtained species of Hetero¬ 
sporium was H. echinulatum which causes a leaf disease of carnations 
very prevalent at this time of the year; and was obtained under natural 
conditions at a nursery at Stellingen near Hamburg. The main part of 
1) Krankheiten der Pflanzen (p. 298, second edition). 
2) Untersuchungen aus dem Gesamtgebiete der Mycologie, 1891, 10, 225. 
Mycologisches Centralblatt, Bd. II. 1 
