278 A MANUAL OP FORESTRY. 



those of Dicranura and Liparis salicis. The plant 

 beetles, Lina populi and tremulce (an Aspen feeder), also 

 attack them. A Longicorn beetle, Saperda populnea, 

 breeds in the twigs of young Aspens, causing gall-like 

 swellings and crippling the growth of the plant. Its 

 congener, Saperda carcharias, breeds in the stems, chiefly 

 of Black Poplar, from 5 to 20 years old, and is a great 

 hindrance in many places to growing the tree. Yarious 

 clear-wing moths, especially Sesia apiformis, and the 

 goat-moth, Cossus, feed in the wood, often in company 

 with Saperda. 



Of fungi, Melampsora species produce a rust on the 

 leaves. 



The Mistletoe is frequently found on Poplars. 



12. LIME-TREE OR LINDEN = Tilia (L.). 



Two species of Lime-tree have to be mentioned : 



(1.) Small-leaved Lime-tree = Tilia parvifolia, Ehrh. 

 (2.) Broad-leaved Lime-tree = Tilia grandif alia, Ehrh. 



The former is the more important forest tree. An in- 

 termediate species is Tilia intermedia, D.C., or Tilia 

 europcea, L., in Britain called the Common Lime-tree. 



a. Utility. 



The wood of the Lime-tree is very light and soft, 

 little durable, and of small heating power. Specific 

 gravity about '45. 



The timber is not fit for building purposes, but used 

 for tool-handles, by joiners and coach builders, for 



