ASCOMYCETES EUASCI DOTHIDEACEAE 



281 



erally with short ostiolum and an apical tuft of hairs or bristles ; one species 

 Chaetomium chartarum common on paper. Sphaeriaceae, with membranaceous 

 perithecia, apex perforated with a simple pore, contains a large number of 

 parasitic fungi like the strawberry rust or spot disease (Sphaerella Fragariae), 

 and the spot disease of the currant (Cercospora angulata). 



FUNGI IMPERFECTI 



The fungi included in this group are simply form genera, many of the 

 species belong to the Pyrenomycetes, some belong to the Phychomycetes, and 

 some to Hymenomycetes. In this connection we shall describe a few only 

 which may cause trouble in forage. 



Helminthosporium gramineum, Rabh. Yellow Leaf Disease of Barley 



Spots in parallel rows, causing the leaves to become marked with yellow 

 lines of pale green color ; mycelium of the tissue colorless ; conidiophores 

 brownish on the surface, spores large 3-6-celled. 



Distribution. Widely distributed in Europe and North America on barley. 



Helminthosporium iurcicum, Pass. Leaf Browning of corn 



Spots sharply limited, conidiophores brownish elongated, bearing several 



brown spores. Widely distributed in Europe on corn, and also in North 

 America. 



Helminthosporium inconspicuum, E. & E. 



Leaves dead and discolored, discoloration sometimes interrupted by spot; 

 of various sizes ; conidiophores brown with several-celled conidia. 



Fig. 100. Yellow Leaf Disease of Barley {Helminthosporium gramineum). a. Hypha 

 arising from short cells. C. Conidium and to the left a cluster of conidiophores. d. 

 Mycelium. 



