USTILAGO. 





very frequently on Avena saliva, al-n on Avena orientalis, 



A. fatua, and A. xt,-i<j*<i m Europe and North America. So 

 common is it that one seldom sees a field of oats free from the 

 hlack smutted ears (Fig. 15G). 



All parts of the flower are attacked, tin- ovary, stamens, 



uluines, and even the awns. The Drains become tilled with 

 the black spore-powder, which shows through the tran-parcut 



I : 



membrane .!' the ovary wall. The di.-eased ear- emerge Inni! 

 llieir eiidc, >in- leaf-sheath-, and bee.nne expired to wind and 

 rain, under the effect- nf which the delicate membrane sn<n 

 becomes ruptured and the .spun-- are hl"\vn or \\ashcd a\\av, 



till only the axes iif the Spikelet a IV left \\itll a fe\\ 



remains of the llnwer. As a rule every Shoot "I' a plant and 

 all the Drains !' an ear aie attacked: if -in-le -rain- >\ 



I hey remain pnnrly de\el..ped. 



'I'he (5-8/u) have a smontli . .r >lj. hi 1 \ _! anul.i i COat, and 



