208 
Mycologia 
Peronospora trichomata Massee, Jour. Linn. Soc. 24: 48. 
pi. 1, f. 1. 1887 
The species so designated is described as causing a serious root- 
rot disease of Colocasia esculenta in Jamaica. This subterranean 
habit is at variance with the usual place of growth of members 
of this family, all of which are leaf parasites, or at least grow on 
the aerial parts of the host. The author’s figures are not con- 
vincing that the fungus in question has been properly referred. 
It would appear from them that the conidial part of the species 
belongs to some genus of Hyphomycetes, probably Verticillium, 
and that the oosporic phase belongs elsewhere in the same group. 
A careful study of material from the herbarium of Professor 
Massee confirms this view. The species, then, is to be excluded 
from the genus Peronospora and transferred to the Hyphomy- 
cetes. As Phytophora Colocasiae Rac. is now known to cause 
a tuber rot in India it is not improbable that this species was the 
real offender, while the fungi described may have been merely 
secondary saprophytes. 
It is not impossible that the material submitted to Massee was 
affected by Phytophthora Colocasiae Racib., and that this fungus 
was overgrown by those which he described. 
Peronospora Nicotianae Speg. 
From time to time various alarmist reports have appeared as to 
the dire consequences of the spread of either the present species 
or Phytophthora Nicotianae Van Breda de Haan into tobacco 
growing countries other than their native lands. It is accordingly 
cause for some little surprise that mycologists have so far failed 
in the majority of cases where they have come in contact with 
this species to recognize it as the dreaded foe for which they were 
looking. The history of the species was given in brief in so far 
as it referred to certain hosts, in a former number of this series. 10 
I11 addition to the cases mentioned in that paper two others deserve 
mention. Harkness and Moore have recorded Peronospora sor- 
dida on Nicotiana Bigclovii from Nevada. This, with the record 
by Professor Farlow of P. Hyoscyami on N. glauca in California, 
would indicate that P. Nicotianae was probably not a formidable 
Bull. Torrey Club 35: 364. 1908. 
