THE FUNGI WHICH CAUSE PLANT DISEASE 



99 



or obovoid, 15-20 x 21-28 n, light-violet; oospores small, 25-30 /z, 

 epispore yellowish-brown, with low, broad reticulations, areolae 

 about 8 Ai; oogonium thin, fugaceous, 32-40 /x. 



This fungus on Vicia and related genera is sometimes quite 

 A 



Fig. 68. — A sporangium with a columella (Mucor). 

 After Sachs. 



serious, particularly on vetch and peas in Europe, Asia and 

 America. 



P. violae de Bary; on cultivated violets and the pansy in Europe 

 and America,^' forming discolored spots; foliicolous or caulicolous, 

 with a pale violet growth, conidiophores fasciculate, short, 2-7 

 times dichotomously branched; ultimate branchlets short, sub- 

 ulate, reflexed; conidia elliptic, short, apiculate, 20-22 x 15-18 y,, 

 violet. 



