USTILAGINE^E. 



321 



there grow out small sporidia, which germinate by sending 

 out a slender hypha ; when this hypha conies in contact 

 with the proper host plant, it penetrates the walls of its 



Fi^. %M. TiUetia caries, d, tra sverse section of an infected wheat-grain ; , ripe 

 spore : /. the firrt stage of germin tion : fir, the formation of a branching 

 Iron, with granular protoplasm u its upper end; A, the formation < 

 l>rauche^ which unite by a kind of conjugation ; the ends of these branches give rise 

 somewhat later to very small spo '" 

 phie a>-e produced, which peueira 



promyce- 

 of Blender 



id when thet-e germinate very slendtr hy- 

 epidermis as at i ; ', mycelium from the 



young ovary of the wheat two small lateral branches are shown, from which spores 

 will develop ; k, spores more fully developed. d, after (Ersted ; e-h, after Tulasne, 

 X 460 ; i-*, after Kuhn, X 300. 



cells, and thus gains admittance to its interior, where it pro- 

 duces a new mycelium* (Fig. 224, i). In Ustilago carbo the 



* This is upon the authority of Kuhn : " Krankheiten der Culturjre- 

 wacbae," 1859. There are some doubts as to the correctness of his 

 observations, and they have not bet-n confirmed bv any one, 



