MILDEWS, RUSTS AND SMUTS 189 
Syn. Ustilago segetum, Dittm. (in part) ; Plowr., Ured., 
p. 273 (in part). 
Occurring in ears of cultivated barley— Hordeuni vul- 
gare. The plant is not infected in the seedling stage, 
hence it is no use treating the seed. Infection takes place 
during the flowering stage, through the stigma, and the 
grain becomes infected, but shows no sign of injury. 
Ustilago segetum, Dittm. ; Plowr., Ured., p. 273 (in part). 
Sori produced in the inflorescence, black, then olive- 
brown, soon powdery ; spores globose, angularly globose 
or oblong, yellowish, then olive-brown, smooth or minutely 
granulated, 5—8 p,; promycelium cylindrical, generally 
3-septate, promycelium spores minute, elliptical, springing 
for the most part from the septa, sometimes from the tip. 
Syn. Reticularia segetum, Bull. 
Uredo carlo, D.C. 
Uredo segetum, Pers. 
Produced in the pedicels and ovary, which are soon 
destroyed; Festuca pratensis, Arrhenatherum elatior, 
Cynodon dactylis, Avena flavescens, Aira caespitosa. Folium 
per'enne, L. temulentum. Europe generally, Africa, Siberia, 
Japan, Queensland, N. and S. America. 
Ustilago sorghi, Pass. 
Spore-mass produced in the ovary, rarely in the stamens, 
soon black and powdery ; spores globose, angularly glo¬ 
bose, or oblong, yellowish olive-brown, smooth, 6—-9 p ; 
promycelium cylindrical, narrowed at the point of emergence 
from the spore, promycelium spores oblong. 
On Sorghum saccharatum, growing in Kew Gardens. 
Cannot be considered as a British species. 
Ustilago maydis, Corda ; Plowr., Ured., p. 278. 
Produced in the inflorescence, also on the stem and leaves, 
in the inflorescence forming very large warts at first covered 
by the wrinkled epidermis ; spores globose or shortly ellip- 
'tical, yellowish-brown, minutely spinulose, 8—13 x 8— 
II p ; promycelium cylindrical, slender, promycelium 
spores spindle-shaped, borne at the septa and at the tip of 
the promycelium. 
Syn. Uredo zeae-mays, D.C. 
Ustilago zeae-mays. Winter. 
Caeoma zeae. Link. 
On cultivated Indian corn— Zeae mays. This parasite 
often proves very destructive in countries where Indian corn 
is cultivated as a crop. 
