210 



THE FUNGI WHICH CAUSE PLANT DISEASE 



Dothichloe Atkinson (p. 199)"' 



Stroma thin, hard when dry, black, especially the outer portion, 

 lighter within, effuse, pulvinate, disciform or armilla-form, partly 

 or entirely surrounding the host; perithecia crowded, confluent 

 with the stroma, but the thin walls of distinctive structure, im- 

 mersed, the apex projecting; asci cylindric, 8-spored; spores fih- 

 form, septate at maturity, and eventually 

 separating at the septa into short seg- 

 ments. 



Likfe the preceding genus, both species 

 D. atramentosa (B. & C.) Atk. and D. 

 aristidse Atk. are grass inhabitors of 

 warm regions of the United States. The 

 former is the commoner species with a 

 wider range of hosts. 



Epichloe (Fries) Tul. (p. 199) 



Stroma effused, subfleshy, at first pale, 

 becoming bright orange, sheathing the 

 host; perithecia immersed or with the 

 ostiola protruding; asci cylindric, 8- 

 spored; spores filiform, many-celled. Of 

 some nine species only one is important. 

 E. typhina (Pers.) Tul. Stroma ef- 

 fused, at first pale, becoming bright 

 orange, forming sheaths 2-5 cm. long 

 Fig. 151.— Epichloe. A, habit around stems of varfous grasses, often 

 section^'c, 'McusTi>,"asc^ destroying the inflorescence; perithecia 

 feld and1indar°*^'' ^"^ ^^^^^ Scattered, partially or entirely im- 

 mersed in the stroma, soft, membranous, 

 concolorous with the stroma, the ostiole rather prominent; asci 

 very long; spores almost as long as the ascus, closely fasciculate, 

 multiseptate, about 2 ^ in diameter; conidia elliptic, hyaline, 

 4-5 X 3 II, preceding the perithecia on the stroma. 



Many grasses are affected, often to serious extent. The mycelium 

 shows first as a yellowish cobwebby growth surrounding the leaf 

 sheath and soon develops a conidial stroma. Later the stroma 



