Pflanzenkrankheiten. 135 



lives chiefly in the parenchyma of the wood and medullar3' rays, 

 advancing in the stem most rapidly in a longitudinal direction. 

 Various facts indicate that the fungus obtains some, if not all of its 

 organic food from tannin. 



Associated with it were eventuall)^ developed fructifications 

 identified as Melanogaster variegatus var. broomiames, ßerk. 



E. M. Wakefield (Kew). 



Hedgcock, G. G., Notes on some diseases oftrees in our 

 national forests. III. (Phytopathology. III. p. 111 — 114. 1913.) 



The present paper is a continuation of observational notes on 

 forest diseases, made chiefly by the writer during August, September 

 and October 1912. 



Is contains remarks about following diseases: 



Polyponis dryophüiis Berk., or a closely related species, as the 

 cause of a disease of the heartwood of the aspen {Popidus tremula). 

 The heart rot is of a yellowish color, interspersed with Strands of 

 brown mycelia near the region where the sporophores originate. 

 In the aspen it is not a piped rot, such as is caused hy P.dryophüus 

 in species of oaks. Besides this, the sporophores vary slightly from 

 those of P. dryophüiis in form and color; it is very probable that 

 the fungus is a different species. 



Avniillaria mellea Vahl attacks the roots of many species oftrees, 

 both in eastern and western forests. 



Of Winter and frost injuries two forms are described: one of 

 them takes place during a severe frost or freeze occurring after the 

 young ends of the shoots have formed a new growth of leaves. 

 The young leaves and stems wilt down and die at once, essuming 

 a reddish colour and remain in a recurved position. 



The other form of injury occurs in mid-winter or in early 

 spring Shows leaves of conifers reddening and drying up., the 

 younger leaves being the most offen affected. The growing tip is 

 often killed and even the cambium layer at one side of the free 

 may be injured, the injury being usually more severe on the west 

 side of the trees affected. Some believes about the cause of this 

 remarkable injury are discussed. 



Acute smelter injury has been observed on lodgepole pines in 

 a number of localities from nine to twelve miles from the smelter 

 where formerly the trees exhibited only the chronic form; also 

 limber pines {Pinus flexilis) and Junipers, which have been conside- 

 red resistant to smoke, do suffer mjury from the fumes, even where 

 the leaves are not apparently injured. Within the region of acute 

 injury the accretion rings of the wood of P. flexilis, show a gradual 

 diminution of growth, and it is a grave question whether it would 

 be possible to reforest with this species in the smelter zone by the 

 process of artificial planting. M. J. Sirks (Haarlem). 



Hörne, A.S., The Control of Peach Leaf Curl. (Contributions 

 from the Wislev Laboratory. XXVIII. Journ. Roy. Hort. Soc. XLI. 

 1. p. 110-114. Äug. 1915.) 



In experiments at Wisley on the control of the disease due to 

 ExonscHS deformmis, it was found that pruning, however thoroughly 

 performed, failed to get rid of the pest. On the other band, mar- 

 kedly beneficial results were obtained by spraying with Burgundy 



