32 
MILDEWS, RUSTS AND SMUTS 
Often destructive to cultivated poppies, covering the 
entire under surface of the leaves with a pale dingy violet 
felt. 
B. Intermediae 
Peronospora effusa, Rabenh. Forming dense, effused 
greyish-lilac patches; conidiophores tufted, emerging 
through the stomata, 200 — 400 X 8 —g p, 2 —7 times 
forked upwards, ultimate branchlets thick, pointed, spread¬ 
ing and curved ; conidia elliptical, with a short, distinct 
stalk, 25 — 35 X 15 — 24 (JL, pale dingy lilac; oospore 
angularly globose, irregularly wrinkled, the wrinkles some¬ 
times combining to form an indistinct and irregular network, 
25 — 38 p, diam. 
Syn. Botrytis effusa, Fres. 
Peronospora chenopodti, Schl. 
Parasitic on leaves belonging to the order Chenopodia- 
ceae, as Chenopodium album, C. muralis, C. glaucum, C. 
polyspermum, C. hyhridum, C. honus-henricus, Atriplex 
patula, A. nitens, A. hastata, A. rosea, Spinacia oleracea, etc. 
Usually forming broadly effused, pale lilac-grey patches 
on the under surface of the leaves. Sometimes proves to 
be very destructive to cultivated spinach. 
Peronospora myosotidis, De Bary. Forming whitish or 
greyish, rather dense patches; conidiophores usually 
emerging through the stomata in pairs, slender, 230 — 600 
X 7—10 p, 6 — 9 times forked upwards, all the branches 
spreading, the upper ones slightly curved, the remainder 
straight ; conidia broadly elliptical, 16 — 24 X 12—15 p,, 
tinged lilac ; oospore globose, wall ornamented with raised 
ridges, combined to form a network, 28 — 34 p diam. 
Syn. Peronospora cynoglossi. Burr. 
Peronospora asperuginis, Schr. 
Parasitic on plants belonging to the order Boraginaceae, 
as Myosotis arvensis, also on species of Lithospermum, 
Cynoglossum, Symphytum, etc. 
Peronospora viciae, De Bary. Patches dense, effused, 
whitish then pale pinkish-grey; conidiophores tufted, 
400 — 700 X 9 —II p, equally, rarely irregularly 6—8 times 
forked above, branches spreading, sometimes more or less 
curved, ultimate branchlets short, tapering to a point ; 
conidia elliptical or broadly pear-shaped, 22—28 x 15—19 
p, pale dingy lilac ; oospores globose, pale yellowish brown, 
wall ornamented with a raised, large meshed network, 
28—32 p, diam. 
