TREES AND SHRUBS 



branches, especially when the Larches are growing in low, damp situations. 

 The fungus is a wound parasite, its spores entering by wounds caused by insects, 

 hailstones, or the fracture of a branch through excessive weight of snow. It 

 consists of tiny white cups of a waxy consistency, having an orange-yellow disk 

 formed of closely packed asci, or spore eases, each containing eight sporidia. 

 Mixed with the cylindrical asci are erect sterile filaments known as paraphyses. 

 The hark is destroyed above the area occupied by the mycelium of the fungus, 

 and when the diseased spots spread so far as to girdle the trunk or branches, the 

 part beyond will die. In damp localities the mycelium appears to spread rapidly 

 through the entire plant, and the cups, or ascosphores, may be developed over 

 every part of the tree. 



As a preventative plantations of Larches should not be made in damp, 

 lowland localities. To check the disease all canker spots should be removed on 

 their first appearance, and the wound dressed immediately with a wash of cor- 

 rosive sublimate in methylated spirit, or with a strong solution of sulphate of 

 iron, and then painted over with tar. 



Maple-leaf Blotch (Rhytisma punctatu/m) occurs as yellow spots nearly 1 in. 

 in diameter, and dotted with disconnected portions of a black scab or crust. 

 The final stage is passed on the fallen leaves, and consists of clavate asci contain- 

 ing eight needle-shaped sporidia. 



Maple Mildew ( Uncinula Aceris) sometimes covers the foliage of Hedge 

 Maple so completely as to give it the appearance of having been drenched with 

 a thin coating of whitewash. The appendages of the receptacles are hooked at 

 the apex. The receptacles enclose eight asci, each containing eight sporidia. 

 The pest may be kept in check by the application of sulphur and lime. 



Mountain Ash Cluster-cups [Rcestelia cornuta). The peridia occur in 



tufts on rusty orange-coloured spots on the under surface of the leaves. 



They are long, cylindrical, horn-like, curved tubes, serrated at the margin, 



but do not split into threads. They are whitish at first, and then become 



yellowish-brown or reddish, and contain brownish-yellow secidiospores. The 



teleutospore stage is said to be the Juniper Jelly-mass (Gym/iosporaHgium 



juniperinum), and the fungus is sometimes described under this name. 



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