MILDEWS, RUSTS AND SMUTS 
i6 
30—40 X 10—18 (JL; oospores globose, yellowish, more 
or less veined, 40—50 p, diam. 
Syn. Plasmopara entospora, Schroet. 
On living leaves, more especially the radical ones, of 
species of Aster and Erigeron. 
SCLEROSPORA, Schroet. 
Mycelium furnished with vesicular haustoria; sporo- 
phores sparingly branched; conidia broadly elliptical, 
tip with a minute wart or papilla, producing zoospores on 
germination ; oospores globose, wall very thick, multis- 
tratose, coloured. 
Remarkable for the very thick wall of the oosphere, and 
in this respect approaching the genus Plasmopara, differing 
however, in the structure of the conidiophores. 
KEY TO THE SPECIES 
graminis. Conidia subglobose. Parasitic on various grasses. 
[kriegeriana, Magnus. Conidia unknown. Oogonia sub- 
globose, with a very thick wall, produced in series in 
the tissue of the host, 60—65 p. diam. Parasitic on 
grasses (Phalaris)']. 
[magnusiana, Sorok. Conidia unknown. Oospore sub- 
globose, wall somewhat wrinkled, thick, brown, 35—50 
p, diam. Parasitic on a species of Equisetum.'] 
Sclerospora graminis, Schroet. Spots formed on the 
leaves, effused ; conidiophores erect, springing singly or 
in small tufts, easily overlooked, about 100 p, high by 10— 
12 p, thick, branched above, branches rather stout, compact, 
usually terminating in 2—3 short branchlets, which bear 
the broadly elliptical, smooth, colourless conidia, 20 x 
15—18 p.; oosphere subglobose, with a reddish-yellow 
wall up to 12 p. in thickness, 50—60 x 40—45 p, ; oospore 
globose, smooth, yellowish. 
S5m. Sclerospora macrospora, Sacc. 
The conidiophores are stouter than in other species, the 
branches being variable in number, short, thick, not spread¬ 
ing, and terminating in 2—3 short branchlets. The whole 
structure soon collapses. 
So far as at present known this parasite is confined to 
grasses, and has been recorded on leaves of species of 
Phalaris, Alopecurus, Setaria and Indian corn (Zea mays). 
Peglioni, an Italian botanist, states that the dissemina¬ 
tion of Sclerospora in cereals is effected by the presence of 
