322 USTILAGINEAE. 



the whole host and hibernates in the root-stock. The spores 

 are developed from the ends of hyphae in the host-tissue, and 

 are either isolated or joined into packets. They germinate 

 easily in water, and produce either a fine germ-tube, or a 

 thick promycelium with four oblong conidia on its apex. The 

 ■conidia are easily detached, and either develop to fine hyphae, 

 or give off secondary conidia. Germination on the whole is 

 similar to that of T. trientoLis. Conidia may be also produced 

 directly on the host-plant ; these were first described by Kiihn, 

 who named them Paipalopsis Irmischiae ; later, however, he 

 succeeded in infecting plants of Primula with the conidia, and 

 in proving their relationship to this Tuburcinia. 



T. Cesatii Sorok. occurs on geraniums in Eussia. 



Here, according to Setchell, the following American genera should be 

 placed : 



Biuillia : B. pustvlata on Sagittaria. 



Cornuella : C. lemnae on Lemna polyrhiza. 



Doassansia. 



Spore-masses consisting of numerous spores capable of ger- 

 mination, enclosed in a layer of sterile cells. The latter are 

 most conspicuous in the species frequenting aquatic plants, and 

 are filled with air, — Brefeld regards them as swimming-organs. 

 The spore-masses lie in groups embedded in the host-plant. 

 The species inhabit plants with an aquatic or moist habitat, 

 and produce on them leaf-spots with black pustules. 



risch ^ investigated the life-history of Boassarisia sagittariac. 

 He found an intercellular mycelium which, inside the stomata, 

 formed sporocarps, consisting of sclerotium-like coils of hyphae 

 enclosing several cells which form spores. The spores on germina- 

 tion give rise to promycelia, which produce sporidia in a manner 

 similar to Entyloma. The sporidia easily germinate in water, 

 and can immediately infect young leaves. The germ-tubes 

 creep on the surface of leaves, and attaching themselves by 

 an adhesion-disc over the wall between two adjacent epidermal 

 cells, they penetrate this wall. The hypha, while passing 



^C. Fisch., Ber. d. devisch. bolan. OeselL, 1884, p. 40.5. Cornu, AnncU. d. sci. 

 natur. xv., 1883. Setchell (Botanical Oazetie, 1894) records the American 

 species and comments on them. 



