BRITISH FOREST TREES 325 



innocuous. Two species of Rhynchites likewise gnaw the 

 young shoots, and buds are destroyed by the caterpillars of 

 >; ierie> ( >f J\>rt/iesia. The omnivorous Melolontha grubs often 

 commit great damage among the tender roots, following along 

 the lines in which the osiers are planted. In the tree-willows 

 the caterpillars of Cossus ligniperda and the larvae of Ptilimts 

 pectinicornis are the worst for boring the holes into the soft 

 mature wood, although species of Cecidomyia, Cryptorhynchiis, 

 Sesia, and Saperda all do more or less damage. Certain 

 species of Adimonia, Cccidomyia, Leucoma and Nematus have 

 received their specific names from the fact of being principally 

 found on willows. Of the osiers, S. riminalis is on the whole 

 the species most liable to injury from insect enemies. 



If allowed to stand too long, tree-willows are attacked by 

 Poly poms sulphureiis, the fungus causing a species of red- 

 rot. Rust on osier-leaves, most frequent on those of one- 

 year-old shoots, is a disease due to species of Mela m 'psora ; in 

 the case of M. Hartigii the intermediate form ( Uredo salicis, 

 D.C.) is developed on the leaves of the previous year, and 

 fructifies in spring after lying on moist soil through the 

 winter, whilst in the case of M. salicis the intermediate form, 

 Caeoma^ finds a host on, and is nourished by, the foliage of 

 other genera, such as cornel, raspberry, bramble, &c. 



Sylricultural Treatment of Willows. Of the tree-willows, 

 the saugh or sallow occasionally finds its way in among 

 mixed woods along with birch and aspen on the moister 

 parts, but the great sylvicultural importance of the whole 

 species rests mainly on the returns they yield as coppice, or 

 from pollarding. Where the saugh occurs spontaneously in 

 mixed forests, it is seldom allowed to remain long, as it is 

 apt to spread and to extend its branches so as to take up 

 more room than, with the monetary returns it has to ofier, 

 it is justified in claiming ; it is therefore usually one of the 

 first nurses or softwoods to be removed along with the 



