83 
SCLEROSPORA GRAMINICOLA (Sacc.) Schroet. 
This fungus has been plentiful on Setaria viridis, often in 
company with Pericularia grisea (Cke.), Sacc. It did much 
damage to that weed and thus did good work for the farmers. 
PLASMOPARA HALSTEDII (Farl.), Ber. & DeT. 
Probably the most destructive mildew in this locality. It 
was collected in abundance on Helianthus tuberosus and [va 
zanthiifolia. On the former host it was often found completely 
covering the under side of every leaf of the plant, which it usually 
killed. It was most plentiful on this host during a rather wet 
spell of weather in early July. On Jva it seldom covered the 
entire plant, but was abundant enough on the lower leaves to 
Cause them to fall off and do serious injury to the plant. This 
species of Jva is very plentiful around Brookings, yet I was un- 
able to find a single unaffected patch of it during July and early 
August. 
PLASMOPARA PYGMA (Ung.), Schroet. 
Early in June a small amount of this species was found on an 
undetermined species of Anemone, but was not found again. 
Though occurring in but a limited area it was quite injurious to 
the host. 
‘Cystopus BLITI (Biv.), DeBary. 
Very plentiful from June to September on Amarantus albus, 
A. retroflexus and A. blitoides. It injured the leaves consider- 
ably, but did not seem to affect the “‘ seed-bearing”’ of the plant 
very much. It remains later than any other species that I have 
observed. 
Cystopus CANDIDUS (Pers.), Lev. 
During the season this species has been collected on Brassica 
nigra, B. alba, Lepidium Virginicum, L. intermedium, Nastur- 
tium Armoracia, N. hispidum, Sisymbrium officinale, Capsella 
Bursa-pastoris and Lepidium sativum. It was quite injurious in 
Many cases, especially on horseradish, where, in connection with 
Ramularia Armoraci@, it did much damage. 
Cystopus TRAGOPOGONIS (Pers.), Schroet. ; 
By far the most destructive species in this genus. Entire 
Patches of Ambrosia artemisiafolia and A. psilostachya were so 
badly injured by it as to ripen but little or no seed. Even along 
