508 



THE FUNGI WHICH CAUSE PLANT DISEASE 



4.5 II. According to Stewart, French & Wilson, spots are caused 

 on alfalfa.^' The American form is distinct from the European 

 and has been described under the name A. imperfecta Pk.^^' 



A. lycopersici Brum. 



Spots red or brown, large, rounded or irregular; pyenidia sparse, 

 minute, black; conidia oblong, constructed, 8-10 x 2.5 m- 



Spots are produced on leaves and fruits of egg plant. 



A. caulicola Lau. causes injury to Melilotus alba.^'" 



A. cookei Alas, is reported on Sweet William. 



A. corticola McA. is the cause of lemon bark-blotch in Australia, 

 killing the trees. ^°^ 



A. graminicola Sacc. occurs on grasses and grains; 



Fig. 351. — Actinonema rosae. 3, branching strand of superficial 

 mycelium; 4, spores. After Southworth. 



A. manihotes Hen. on cassava in Africa. 

 A. tremulae Sacc. occurs on aspen; 

 A. melutispora B. & Br. on ash. 



Actinonema Fries (p. 505) 



Pyenidia very small, not ostiolate, with a radiating mycelial 

 growth on the surface of the host; conidia elongate, on short 

 conidiophores. 



A genus of about fifteen species, chiefly leaf parasites. 



A. rosse (Lib.) Fr.^'*- "« 



Spots rounded or irregular, black or purple, epiphyllous, often 



