Crack Willow 



191 



10. LYALL'S WILLOW Salix Lyallii (Sargent) Heller 

 Salix lasiandra Lyallii Sargent 



Lyall's willow is closely related botanically to Salix lasiandra Bentham, just 

 described, but it is maintained, by observers 

 who have studied it in its native regions, to 

 be readily distinguishable from that species. 

 It grows along streams and lakes from the 

 Yukon Territory to British Columbia, Mon- 

 tana, and Oregon, perhaps extending also into 

 CaHfomia. 



The differences relied upon to separate 

 this tree from Salix lasiandra Bentham are 

 its larger leaves, sometimes 20 cm. long and 

 4 cm. wide, mostly rounded or somewhat 

 heart-shaped at the base, and bright white 

 or very pale green on the under side, form- 

 ing strikingly conspicuous foliage; the leaf- 

 stalks are also rather longer and more 

 glandular, and the fruiting catkins larger, 

 sometimes 7.5 cm. long; the bracts of the 

 catkins are less glandular, sometimes quite 

 entire-margined. 



Its wood is very similar to that of the 

 Western black willow. 



Fig. 149. Lyall's Willow. 



II. CRACK WILLOW Salix fragilis Linnsus 



Fig. 150. Crack Willow. 



This European species has been planted 

 for ornament and distributed along streams 

 by its brittle twigs v/hich strike root readily, 

 and has become naturahzed in eastern 

 North America from Newfoundland to 

 Pennsylvania. It is a tall slender tree, 

 sometimes 25 meters high, with a trunk up 

 to 2 meters in diameter, though these di- 

 mensions are perhaps not reached by any 

 individual outside of Europe. The name 

 Crack willow is in allusion to the brittle- 

 based twigs which are easily broken away, 

 the rupture accompanied by a cracking 

 sound. 



The bark is rough and gray-brown, 



