416 



GRASS-RUST. 



RUSTS. 



3 Grass-rustj {Puccmia graminis, P.) Order Basidiomy 

 cetes. Sub-order Uredineae. 



Fio, 160.— Several stages of grass-rust. A, young mcidium fruit; r, section of Bar- 

 berry leaf; a ik lecidium fruit; ,s p, sperinagonia; 11., a mass of teletitospores on a leaf 

 •of a grass; ///., three uredospores, « v, with one teleutospore, <.— (From DeBar j-.) 



Forming orange-red, powdery spots and lines o\\ the leaves 

 and stems of cereals and meadow-grasses, that give place later to 

 dead-black velvety lines. 



The sheaths and culms of the smaller grasses, especially quack 

 grasses and red-top, are very often attacked by this rust (called 

 mildew and brand in England), which produces the same dis- 



