96 British Urediiiece and Ustilagincff. 



cellular, and pervades all parts of the affected plants, 

 especially the cortical parts of the stem, and also to some 

 extent the pith. It also occurs in the upper part of the 

 root-stock. It is hyaline, about 4"5ju wide, richly branched, 

 and septate. Its contents are colourless and vacuolated. 

 The spores are formed inside the mycelial hyphae, where 

 it becomes coarsely granular, much after the manner of 

 Entyloma.* Woronin t finds that the mycelium is abun- 

 dantly provided with very marked haustoria, which enter 

 the cells. These botryform prolongations enter and occupy 

 a third or a half of their interior. Germination takes place 

 in autumn. Specimens gathered in June germinated in 

 October and November. The epispore splits, and the 

 endospore grows out as a blunt cylindrical promycelium. 

 At its extremity it emits a clus':er of from four to seven 

 apical branches. The outgrowth of the endospore is at 

 first often in the form of two equal branches, one of 

 which develops into the promycelium, while the other 

 ceases to grow and has become emptied of its protoplasm, 

 which passes into the developed branch. Towards the 

 upper half of the promycelium a septum appears, cutting 

 off the protoplasm above from the empty tube below ; but 

 true spore- formation was not observed. 



Tiibercinia. — The germination of the spores of T. trien- 

 talis has been worked out by Woronin. | Teleutospores 

 collected at the end of September and the beginning of 

 October were found often to have already germinated upon 

 the plant. Placed in a dam.p atmosphere, they germinated 

 freely after the manner of Tilletia, each spore producing a 

 promycelium surmounted by a cluster of spores. All the 

 teleutospores of one spore-ball do not germinate at the 



* De Bary, loc, cit. 



t Woronin, loc. cit., pp. 27, 28, t. iv. figs. 27-35. 



X Woronin, " De Bary und Woronin Beitrage," 5 reihe (18S2), pp. 4-16, 

 t. i., ii., iii. figs. 1-12. 



