1922] MILBRAITH—ALTERNARIA 323 
Black leaf spot of cabbage has been attributed to the fungus 
Alternaria brassicae for a long time. Harter and Jones? state 
that the black spot fungus may attack the cabbage plant at any 
stage of its growth, but it is not common except on the older leaves 
in the field or on heads in storage. In the field it appears on the 
lower or outer leaves of the maturing plant as distinct, roundish, 
Fic. 2.—Types of conidia and conidiophores of Alternaria oleracea from cabbage 
leaf 
black spots, commonly marked with concentric brown zones. 
Saccarpo? describes the fungus A. brassicae (in translation) as 
follows: 
Hyphae short, compact, little branched, even growth, in tufts; 
conidia deciduous, elongate, fusoid, clavate, size 60-80 u by 14- 
18 uw, 6-8 septate, muriform, olivaceous; fungus found on decaying 
and old leaves of Brassica oleracea. 
2 HARTER, L. » an Jones, L. R., Cabbage diseases. U.S. Dept. Agric. Farmers’ 
Bull. 925. figs. 13. 
3 Saccarpo, P. ee ne Fungorum 4:546. 1886. 
