284 Studies in Forestry [CHAP. xm. 



B. Of Broad-leaved Trees : 



i. Nectria ditissima. Beech canker. Mainly attacking 

 Beech, Oak, and all other similar trees (except Birch ?;. 



Minor disorders are due to Nectria cinnabarina on Maples, 

 Elm, Lime, and in particular Horse Chestnut, and Polyporus 

 sulphureus on Oak, Poplar, Tree Willows, Birch, and Larch. 



III. ON ROOTS AND BASE OF TRUNK. 



A. Of Conifers : 



1. Agaricus melleus^ the Honey fungus, an edible mushroom. 

 It mainly attacks conifers, but especially Spruce, or Scots 

 and Weymouth Pines. 



2. Trametes radidperda^ Root-fungus. It mainly attacks 

 Scots and Weymouth Pines, Spruce, and Silver Fir. 



B. Of Broad-leaved Trees: 



i . Rosellinia querdna, Oak-seedling fungus, occurring in one 

 to three-year-old Oaks principally. 



Details with regard to the Appearance, Causes and 

 Effects of the Chief Fungoid Diseases, and the Pre- 

 ventive Measures adoptable against their spread. 



I. FUNGOID DISEASES OF THE FOLIAGE. 



A. On Conifers: 



i. Hysterium pinastri, Schrad., the Pine scab or scurf, is 

 one of the principal causes of leaf-shedding in young plantations. 

 During late summer and autumn small brown spots, which 

 contain the characteristic mycelium of this fungus, make their 

 appearance on the young foliage of Pines. Early in the following 

 spring the needles wither, redden, and drop off. If the winter 

 has been mild and the spring is wet, the blackish fruits or 



