48o 



DISEASES OF CULTIVATED PLANTS 



Appel and Laubert, Ber. Deutsch. Bot. Ges., 23, p. 218. 



Clinton, State of Conn. Exp. St. Rep. (1907-8). 



Frank, Ber. Deutsch. Bot. Ges., 16, p. 280. 



Harz, Einige Neue Hyphomyceten, p. 129, pi. 31 (1871). 



Johnson, Econom. Proc. Roy. Soc. Dublin, i, p. 161 (1903). 



Massee, Kew Bull., Jan. 1909. 



EXOSPORIUM (LINK.) 



Stroma compact, convex or with the centre depressed; 

 spores elongated, many-septate, coloured. 



This genus is closely allied to Coryneum, if indeed there is 

 any real difference between the two. 



Larch branch fungus (Exosporium laridnum, Massee) 

 occurs on living branches of the larch, and although directly 

 of no economic importance, yet indirectly it is sometimes the 

 cause of serious injury, in that the cracking of the bark, and 

 subsequent oozing out of sap and resin, enables the spores of 



^f 



FlG. 143. Exosporiiim laricin um. i, fungus on pine 

 bark ; 2, fruit of fungus ; 3, sections of same ; 4, conidia. 

 Figs. 2-4 mag. 



the canker fungus (Dasyscypha) to gain an entrance into the 

 tissues, and subsequently form a canker wound. 



The fungus occurs under the form of minute, black dots in 

 crowded clusters on the bark of young shoots. Stroma more 

 or less circular, often depressed in the centre, and resembling 



