Wilson: Studies in North American Peronosporales 195 
Bremiella gen. nov. 1 
Conicliophores from the stomata, the branches few and quite 
long, the main axis breaking up dichitomously or pseudo-mono- 
podially, the ultimate branchelets quite long and terminating in an 
apophysate enlargement ; conidia papillate, basially constricted 
and somewhat pyriform, hyaline, germinating by zoospores: 
oospores conspicuously wrinkled, free in the oogonium. 
Type, Peronospora megasperma A. Berlese. 
The downy-mildew of the violets of Europe and of America are 
two very distinct fungi which should never have been confused. 
Peronospora Violae De Bary is a typical member of the genus. 
The American form, which was first recognized as a distinct spe- 
cies in 1899 and named Peronospora megasperma , is such an ano- 
malous form that the same author later transferred it to the genus 
Plasmopara. 
Apparently the first collection of the American species was 
made in April 1882 by Professor F. S. Earle, who supplied mate- 
rial to Ellis for his North American Fungi. Of this material 
Doctor Farlow writes “ The specimens received from Mr. Earle 
were collected in April 1883 (sic), and can be referred without 
doubt to this form their resemblance to P. effusa var. minor’’ 2 
A note in a packet of this same collection in the Earle herbarium 
at the New York Botanical Garden calls attention to the swollen 
ends of the conidiophores and credits Professor Burrill with hav- 
ing pointed out the essential differences which we have noted 
between this and the European species. Upon the same authority 
the conidia are also said to germinate by means of zoospores. The 
conflicting evidence leaves it an open question whether or not both 
of the violet-inhabiting species occur in America. It appears, 
however, from an examination of the material at hand that in all 
probability we have in America only one species. This we have 
designated Bremiella megasperma (A. Berlese) G. W. Wilson. 
1 Hyphis conidiophoris solitaris vel fasciculatis, e stomatibus plantarum 
erumpentibus, dichotomo-vel pseudo-monopodio-ramosis ; ramuli terminalis 
longis, apice in vesiculam apophysatam abientibus ; conidis hyalinis, pyri- 
formibus, apice papillatis, per zoosporas evacuantia ; oosporis subrugosis. 
2 Bot. Gaz. 8: 328. 1883. 
