VALSA. 



225 



where leaves of the alder are dried in summer for use as 

 winter-fodder for goats. 



In the branches attacked, a mycelium is developed in the 

 vessels of the wood, whereby the supply of water is stopped 

 and the bark dries up. Black lens-shaped stromata arise 

 under the epidermis of the twig and rupture it. The perithecia 

 are produced under the stromata in the bark, and communicate 



Fig. 109. — Valsa oxy&toma on Alnus viridis. Ay Portion of branch with stroma 

 of Vatsa breaking through the periderm at foxir places. .B, Enlarged section 

 through a stroma from A. C, Asci and ascospores, isolated from a perithecium. 

 B, Portion of younger branch with periderm ruptured by stromata, in which, 

 however, the perithecia. are not yet developed. E, Enlarged section through a 

 stroma of D. (After v. Tubeuf.) 



with the exterior by means of long projecting necks. The 

 asci contain eight unicellular spores of a slightly bent, rod- 

 like shape. Maturity is reached on the dry dead twigs. 

 Externally this disease is identical in appearance with one 

 I ascertained to be due to a beetle (Cryptorhynchus lapathi), 



