334 



THALLOPHVTES. 



formed in cushion-like masses of mycelium upon densely-crowded branches (basidia) 

 directed outwards immediately beneath the epidermis. They contain red granules and 

 are perceptible with the naked eye as narrow long red projections upon the leaves and 

 stems of Grasses. These uredospores are dispersed after the rupture of the epidermis, 

 and germinate after some hours upon the surface of the Grasses (P'ig. 224, D) : in these 

 they form new mycelia which, in 6 or 10 days, bear uredospores again. While 

 the Fungus is multiplying in this manner for several generations on Grasses during 

 the summer in its uredo-form, the production of a new form of spores begins in the 

 older uredo-fruits ; the long two-celled teleutospores begin to be formed near the 

 roundish uredospores (Fig. 223, ///, /). The formation of uredospores in the uredo- 



FlG. 22i. — Pucctttta Gramuiis. A germinating- teleutospore t, the promycelium of which forms the sporidia sp; 

 B a promycelium (after Tulasne) ; C a piece of the epidermis of the lower surface of the leaf of Berberis vulgaris with a 

 germinating sporidium sp ; i its germinating filament penetrating the epidermis ; D a germinating uredospore 14 hours after 

 dissemination (after De Bary, /. c). 



fruits then entirely ceases, and teleutospores only are produced (Fig. 223, 77), and with 

 them the period of vegetation closes. The teleutospores persist on the grass-haulms 

 through the winter, and do not germinate till the spring ; they emit from their two cells 

 short septate germinating filaments (Fig. 224, A, B), the promycelia, at the ends of 

 which, on slender branches, the sporidia are produced. These sporidia develope a new 

 mycelium only when they germinate on the surface of the leaves of the Barberry; their 

 mode of germination differs from that of the other forms of spores, their germinating 

 filaments penetrating, as in the Peronosporeae, into and through the epidermis-cell (Fig. 

 224, C, sp and /), and thus reaching the parenchyma. They there form a mycelium 



