532 Report of the Mycologist op the 



several thousand young trees, from four to six feet in height, scarcely 

 a tree could be found but what was more or less diseased. Early in 

 July the young leaves on the terminal twigs take on a yellowish- 

 green color and then blacken and die at the tips as if slightly frosted. 

 Some of the very youngest leaves may be entirely dead. From this 

 time on to the end of the growing season the majority of the young 

 shoots are killed as fast as they appear. Upon the death of the 

 terminal shoot, the two lateral buds (the leaves are opposite) develop 

 into shoots each of which after growing a short distance is in its turn 

 killed part way back and develops two lateral shoots. By the 

 repetition of this process there is formed a compact, much-branched 

 "head " which must be pruned away before growth commences the 

 following season. 



The cause of the trouble is a fungus, Gleosporiiim apocryptum, ^ 

 E, & E., the numerous spores of which appear on the dead shoots 

 and on the under surface of the leaves, as a cinnamon-brown powder : 

 Another member of the same genus, Gleosporium nermseq-num, ^ 

 (Fckl.) Sacc, causes a similar fasciation of the twigs of large sycamore 

 trees — a disease exceedingly common in south-eastern New York. 

 The maple Gleosporium is confined entirely to young trees, and is, 

 therefore, troublesome chiefly in nurseries. Rapid growing trees 

 appear to be more subject to it than trees making slow growth. 



There is good reason for believing that the disease can be pre- 

 vented by spraying with Bordeaux mixture or some of the other 

 compounds of copper ; but at least three applications would probably 

 be necessary and Mr, Hicks is of the opinion that it is less expensive 

 to prune away the diseased heads than to sj^ray three times. 



Y. WITCHES' BROOMS ON CHERRY TREES. i 



In Europe the cultivated cherries, Pruniis Avhim and P. Cerasus, 

 are attacked by a disease which the Germans call Hexenbesen 

 (witches' brooms). The fungus which causes it is closely related to 

 the leaf-curl fungus of the peach. Formerly it was considered to 

 be identical with the disease on the peach, but Prof. Sadebeck, in a 

 recent monograph, 2 makes it a distinct species, giving it the name 



1 Identified by Mr. J. B. Ellis. Described in Journ. of Mycoloey, Vol. IV, p. 53. 



2 Described and figured in U. S. Dept. of Agr. Report for 1888, p. 3t7. 

 1 This article appeared in " Garden and Forest" for July 3, 1893. 



3 Die parasitischen Exoasceen. 



