2i6 PLANT DISEASES 



vated barley, but differs from the last in the spore-mass 

 becoming pulverent and dispersed as soon as mature. 



Very resistent to fungicides, and best treated with the 

 hot-water method, having previously been soaked for 

 several hours in cold water. 



Ustilago soi'ghi^ Pass. — Spore-mass forming in the ovary 

 of Sorghu7n vulgare and S. saccharatii??i, and completely 

 filling it with a dusty mass of spores. The anthers are 

 also attacked. As a rule all the flowers forming a head 

 are attacked. 



Ustilago cnie?ita, Kiihn. — This smut attacks the top of 

 the culm and branches of the inflorescence, rarely the 

 ovary of Sorghum vulgare^ forming reddish-brown patches 

 and causing much distortion of the parts attacked. 



Ustilago reilia?ia, Kiihn. — Attacks Sorghum vulgare and 

 ^. halepense, and Zea 7nays in different parts of the World. 

 The ear is attacked, the spore-masses roundish or elongated, 

 at first enclosed in a silvery white membrane, then pulverulent 

 and soon dispersed, leaving only the more persistent parts 

 of the ear as a skeleton. Brefeld has experimented with 

 this species, and discovered that the spores germinate in 

 a nutritive solution after being kept for eight years. The 

 secondary spores also, if kept dry, retain the power of 

 germinating for a long time. 



Ustilago emodensis, Berk. = Ustilago treubii^ Solms. — 

 Professor Solms Laubach has given an interesting account 

 of this parasite — Ann. Jard. Bot. Buite?izorg, vol. vi. p. 79, 

 pi. ix. (1887) — but has overlooked the fact that it was 

 previously described by Berkeley — Hook. Journ. Bot.., vol. 



