488 THE FUNGI WHICH CAUSE PLANT DISEASE 



P. idsecola Cke. forms spots on cultivated species of Sida and 

 Hibiscus. 



P. dianthi West, grows on Dianthus leaves. 



P. primulsecola Desm. occurs on Primula leaves.^ 



Amphigenous; spots large, white, light margined; pycnidia epiph- 

 yllous, numerous, prominent, globose, black; conidia subglobose. 



P. violae Desm."' ^ 



Amphigenous, spots white, round; pycnidia numerous, minute, 

 brown; spores minute, subcylindric, 10 n long. 



Common, causing leaf spots on pansy and violet. 



P. hydrangeae E. & E.^^ 



Spots 1.5-1 cm. or more, rusty brown, margin narrow, raised, 

 at first shaded with purple; pycnidia epiphyllous, lenticular, 

 100-115 n; conidia oblong, 10-12 x 2.5-3.5 /*. 



On Hydrangea causing leaf spots. 



P. syringse West, is common on lilac. 



P. halstedii E. & E. 



Amphigenous, spots roimdish, reddish-brown, J^-li^ cm. con- 

 centrically zonate, pycnidia few, lenticular, 100-150 ii, immersed; 

 conidia broadly f usoid-oblong, 15-20 x 5-7 ii. Causing a leaf spot 

 of the lilac. 



P. cruenta (Fr.) Kick. 



Spots subcircular, reddish, becoming paler in the center; pycnidia 

 gregarious or scattered, globose-lenticular, dark olivaceous; conidia 

 ovate-oblong, 14-16 x 5.5-6.5 /i ; conidiophores, cylindric, 10-12 x 4 /i. 



It causes leaf spots of cultivated Solomon's Seal. 



P. cyclaminis Brun. occurs on cyclamen; 



P. digitalis Bell on digitalis. 



P. chrysanthemi E. «fe D."* 



Spots purplish-brown, pycnidia 80-100 ix; conidia 4-5 x 2.5-3 m- 



It causes leaf spots on cultivated chrysanthemums. 



P. leucanthemi Speg. is occasionally found in spots of chrysan- 

 themum leaves. 



P. richardis Hals.^ is common as a leaf spotter of the calla 

 lily but has not been satisfactorily described. 



P. opuntise Sacc. & Speg. occurs on various of the Cactacese; 



P. liliicola Sacc. on lily; 



P. vincse minoris B. & K. on Vinca minor; 



