UROCYSTIS 347 



appearance and smell, but is distinguished by having perfectly 

 smooth spores. 



Spore-mass formed in the ovary, deep brown with an olive 

 tinge, foetid ; spores globose, elliptical, etc., variable in form 

 and size, pale olive brown or sometimes almost cream-colour, 

 smooth, 17-21 /A, or 15-26 x 10-15 /x. 



Tilletia deripiens, Winter ( = Tilletia secalis, Kiihn), is pro- 

 duced in the ovary of rye, also in several wild grasses. Spore- 

 mass blackish-brown. Agrostis pumila (L.) is nothing more 

 than Agrostis vulgaris dwarfed by this fungus. 



Spore-mass formed in the ovary, blackish-brown, foetid; 

 spores globose, angular, or elliptical, clear brown, with raised 

 ridges anastomosing to form a network of irregular, small 

 meshes, 20-27 ju. diam. 



Tilletia corona, Scrib. (=T. horrida) attacks the grain of 

 rice (Oryza sativa, L.), which becomes filled with a black 

 mass. 



Spores dark brown ; warted, 22-26 //, diam. 



This smut also attacks species of Homalocenchrus and 

 Panicum, 



Anderson, A. P., Bot. Gaz., 27 (1899). 



UROCYSTIS 



Sori erumpent, large, black, powdery ; spore-clusters con- 

 sisting of one or more central, fertile, dark-coloured cells, 

 surrounded by smaller, pale-coloured, sterile, peripheral cells. 



Rye smut (Urocystis occulta, Rab.) is most abundant on 

 rye, but also occurs on wheat and barley, and according to 

 Wolff it attacks wheat in Australia. It forms long grey lines 

 on leaf-sheaths, leaves, and upper part of the culm. The 

 streaks become black and powdery, the tissues are more or 

 less destroyed, and the ear is arrested in its development. 

 The culm often bends over and breaks at the point attacked. 



Spore-clusters 17-24x15-20 /x, central ones dark brown, 

 sterile ones pale, forming a broken zone round fertile ones. 

 - Treating the seed with formalin, as recommended for 

 Ustilago avenae, has proved satisfactory. 



Prillieux, Malad. des Plantes Agric., i. p. 187. 



