Witson: NortH AMERICAN PERONOSPORALES 391 
Phytophthora omnivora de Bary, Bot. Zeit. 39: 584, 619. pl. 5. f. 
33-47. 1881. 
This species has long been a scourge in Europe on account of 
its attacks upon seedlings and succulents, its hosts including rep- 
resentatives of fifteen families ranging from Pinaceae to Scrophu- 
lariaceae. Until quite recently this species was not reported from 
other countries, its first record from foreign quarters being in con- 
nection with a serious outbreak of a pod-rot of cacao in the island 
of Trinidad.* Material was sent to Massee, who identified one of 
the fungi concerned as Phytophthora omnivora de Bary. His de- 
scription + is of a popular nature and would apply equally well to 
any one of several groups of fungi, while his figures are unmis- 
takably of a species of Phytophthora of the same type as the pres- 
ent one. The conidia are somewhat more elongate and attenuate 
than usual. This, taken with the habitat, suggests that the pod- 
rot of the cacao may be caused by a distinct but closely related 
species, but no definite statement can be made without first exam- 
ining fresh material. Since the first report of the outbreak of the 
disease, it has been reported from various other localities in the 
West Indies, South America, Asia and Africa. The history, dis- 
tribution and nature of the disease are fully discussed by Howard.f 
The species is also included by Freeman in his Minnesota Plant 
Diseases § as a pest in seed-beds. 
5. PHyropHTHora INFESTANS (Mont.) de Bary, Jour. 
Roy. Agr. Soc. England II. 12: 240. 1876 
Botrytis infestans Mont. Mém. Inst. France 1845: 313. 1845. 
Peronospora infestans Casp. in” Rabenh. Herb. Viv. Myc. I. 2879. 
1854. 
As one of our worst plant diseases is caused by the present 
species its distribution is rather well worked out. While the fun- 
gus is not so prevalent, except in localities where the potato is cul- 
tivated in large commercial quantities, the range of both appears 
to be coextensive. It is, however, much more destructive in the 
* Hart, Bull. Trinidad Bot. Gard. 3: 167-169. Ja 1899. 
+ Kew Bull. Misc. Inf. 1899: 1-6, plate. 1899. 
t West Indian Bull. 2: 190-211. Igol. 
% Page 382. 1905. 
