THE FUNGI WHICH CAUSE PLANT DISEASE 611 



H. echinulatum (Berk.) Cke.^'- '"^ 



Spots gregarious, on fuscous areas; conidiophores fasciculate 

 from a stromatic base, 150-200 x 8 n, rarely shorter, flexuose- 

 nodose, fuliginous; conidia at the nodes, oblong-cylindric, rounded 

 at the ends, 2 to 3-septate, 40-50 x 15-16 n, slightly constricted, 

 roughened, brownish. 



It causes a destructive mold on carnation leaves and stems. The 

 first epidemic was noted by Sorauer in Berlin in 1883. 



H. gracile (Wal.) Sacc. was determined to be the cause of dis- 

 ease of Iris, Narcissus and other Monocotyledons.'"* 



H. variable Cke.^ 



Conidiophores flexuose, slender, more or less nodulose at the 

 septa; conidia cylindric oblong, 2 to 4-septate, minutely warted, 

 20-25 X 7-10 M, pale olive. On spinach. 



Other parasitic species are: 



H. omithogali Klotz. on Liliaces; 



H. laricis C. & M. on larch leaves; 



H. auriculi Mas. on cultivated Auricula; 



H. syringse Oud. on lilac leaves.*' 



H. minutuliun C. & M. causes disease of hops. 



Napicladium von Thtimen (p. 609) 



Conidiophores short, subfasciculate, smoothish; conidia acroge- 

 nous, solitary, large, oblong, 2 to many-septate, smoothish. 



A small genus. 



N. janseanum Rac. is on rice. 



N. soraueri is a form of Ventiu-ia insequalis with somewhat 

 atypical napiform spores. See p. 253. 



Helminthosporium Link (p. 609) 



Conidiophores erect, rigid, subsimple, fuscous; conidia fusoid 

 to elongate-clavate or cylindric, pluriseptate, fuscous, smooth. 



In part=Pleospora. See p. 259. 



About two hundred species; several are important pathogens, 

 others saprophytes. 



The species show biologic differentiation into races similar to 



