THE 'FUNGI WHICH CAUSE PLANT DISEASE 521 



one in the center of each spot, but slightly prominent; conidia 

 cylindric or clavate-cylindric, 10-25 x 1.5-2 n. 



On watermelon leaves. 



S. cucurbitacearum Sacc. is also on cucurbits. " 



S. cannabina Pk. is on hemp producing leaf spots. 



S, nicotianse Pat. is reported from France as the cause of tobacco 

 leaf spotting."" 



S. doUchi B. & C. 



Spots white, with a broad, light brown margin; conidia straight, 

 subfusiform, 3-septate, 40 m- On cowpeas."^ 



S. medicaginis Rob. & Desm. is on alfalfa. 



Spots whitish, angulate-subcircular, confluent; pycnidia len- 

 ticular, 70-90 ix; conidia slender, vermiform, tortuous, 60-70 x 1 m, 

 septate. 



S. petroselini Desm. 



Spots brown, in age white, amphigenous; pycnidia epiphyllous, 

 minute, olivaceous, promi- 

 nent; conidia filiform, straight 

 or curved, 35-40 x 1-2 y.. On 

 parsley. 



S. petroselini apii Br. & 



CaV.^^* 122-126 



This common and very de- 

 structive fungus on celery 

 leaves was first described in 

 Italy by Cavara and in 

 America it was early noted 

 by Chester 1^2 and Halsted.^^ 



The pycnidia are abundant in „ „„„ „ ,....„. ,. 



. Fig. 360. — S. petroselini apu. Pycmdium 



the leaf spots and in the case showing spores oozing through the ostiole. 



of stored celery they are ^^^'^^'^''■ 



foimd scattered over the blanched petioles. Essentially it is only 



a host variety. 



S. lycopersici Speg."^* ^^' ^^ 



Spots large, often confluent and covering the entire leaf, sordid 

 cinereous, subindeterminate; pycnidia scattered, hypophyllous, 

 lenticular-hemispheric, prominent, membranous; conidia elongate, 

 cylindric, 70-110 x 3.3 11, pluriseptate. 



