GNOMONIA 199 



leaves soon become yellow and dry, and when the disease 

 is abundant, early defoliation affects the fruit and also 

 injures the tree. The ascigerous form of fruit is found 

 during the winter on fallen leaves that had been attacked by 

 the conidial form of the fungus. 



Silkworms may be fed on leaves attacked by the fungus 

 without experiencing any injury, only the green, healthy 

 portions of the leaf being eaten. 



Ascigerous form. Perithecia hypophyllis, superficial, black ; 

 asci short, base inflated, 50-55X10-15 /*, spores oblong, 

 cuneate, hyaline, i-septate, 17-25x5-5*5 p. 



A damp season favours the disease, and trees planted in 

 damp situations suffer most severely. When the leaves are 

 required for silkworms, spraying with Bordeaux mixture 

 cannot be practised, otherwise if sprayed early in the season 

 some good might result, but so far as I am aware, this 

 method has not been tested. As infection depends on the 

 presence of the ascigerous form of the fungus growing on the 

 dead, fallen leaves, all such should be collected and buried. 



Berlese, Fungi Moricolae^ p. 24. 



Prillieux, Malad. des Plantes Agric., 2, p. 280 (1897). 



MYCOSPHAERELLA QOHANS.) 



Perithecia as in Sphaerella ; asci containing sixteen 

 i-septate, hyaline spores; paraphyses absent. 



GNOMONIA (CES. and DE NOT.) 



Perithecia seated in the tissue of the host, glabrous, with a 

 central or lateral, elongated ostiolum ; asci 4-8-spored; 

 spores elongated, hyaline, i-septate ; paraphyses absent. 



Minute fungi usually growing on leaves, the beak or 

 ostiolum is elongated and projects beyond the surface of the 

 leaf. 



Cherry leaf scorch (Gnomonia erythrostoma^ Auersw.) is 

 well known as the cause of a serious cherry-tree disease, both 

 in this country and on the continent. The symptoms are 

 very characteristic, and cannot be mistaken for any other kind 

 of injury. The leaves are attacked during the summer by the 

 conidial stage of the fungus, which occurs under the form of 



