USTILAGINACEAE 401 



on germination producing a short, septate promycelium, 

 which bears minute, lateral, and terminal secondary 

 spores. 



Ustilago avenae, Jensen. Spore-mass blackish-brown, 

 soon pulverulent, formed in the ovary ; spores globose or 

 broadly elliptical, 6-8 ft diam., or 7-9x6-7 //, delicately 

 verruculose ; promycelium septate, sporidiola oblong, 

 produced at the septa. 



Var. levis, Kell. and Swing., 11. Rep. Agr. Kansas, p. 25, 

 tab. 5, f. 56-60. Spores smooth and slightly darker in 

 colour than in the type form. 



Ustilago tritici, Jensen, in Kell. and Swing., 11. Rep. 

 Agr. Kansas, p. 214 and 262, tab. 2 and 6. Spore mass 

 dark olive-brown, loose, formed in the ovary ; spores 

 ovoid, elliptic, or subglobose, 5 '5-7*5x5 -6 /x, dilute olive, 

 minutely verruculose ; promycelium branched, septate ; 

 secondary spores. 



Forma folicola, P. Henn., Zeitschr. fiir Pflanzenkr.^ 1894, 

 p. 139. Developed on leaves and leaf-sheaths of Triticum 

 vulgare\ spores either quite smooth, or delicately punc- 

 tulate, yellowish olive-brown, 4-5-7 X 4*5-6 /x. 



Ustilago nuda, Kell. and Swing., u. Rep. Agr. Kansas, pp. 

 215 and 277, pi. 2, f. 7-17. Spore-mass olive-brown, pro- 

 duced in the ovary, soon free and powdery ; spores ellip- 

 tical to globose 5-7 X 5-6 ft, olive-brown. The promycelium 

 does not produce secondary spores, but forms a sparingly 

 branched, septate mycelium. 



Ustilago hordei, Kell. and Swing., n. Rep. Agr. 

 Kansas, pp. 215 and 268, pi. 2, f. 2-6. Spore-mass black, 

 compact, not becoming pulverulent, and enclosed in the 



2 C 



