FOREST TREES OF THE PACIFIC SLOPE. 219 



OCCURRENCE. 



Confined to wet borders of mountain and lower streams, in gravel and sand. Forms 

 clumps and patches, often mixed with Bigelow willow and white alder. Climatic and 

 other requirements undetermined. 



Western Black Willow. 



Salix lasiandra Bentham. 



DISTINGUISHING CHARACTERISTICS. 



Western black willow, like the preceding species, is known throughout its 

 range simply as " black willow," on account of the color of its bark. The 

 bark is distinctly cut by cross-seams into flat plates longer than they are wide. 

 The form of its leaves and twigs affords the principal means of distinction. 

 Ordinarily it is 25 or 30 feet high and from 14 to 20 inches in diameter ; some- 

 times from 40 to 50 feet high and from 24 to 30 inches through ; in some parts 

 of its range, often a bushy tree under 10 feet high. The clear trunk, rarely 

 straight, is short, and the long, straight limbs grow upright, producing an open, 

 unsymmetrical crown. The mature twigs are rather large, and clear reddish 

 yellow to brown. The leaves (fig. 89), deep yellow green at maturity and 

 about 4£ to 5 inches long, are shiny on their upper surface, whitish beneath, 

 the large mid-veins reddish yellow and the leaf stems, with two or more black- 

 ish spots (glands) at their juncture with tbe leaf blade, smooth or slightly 

 and minutely hairy. As a rule the largest leaves are produced at the ends 

 of the branches, apparently on account of the more vigorous growth there. 



RANGE. 



California (west of the Sierra Nevada) ; western Oregon, Washington, and southern 

 British Columbia (Selkirk Mountains) at middle elevations. 



OCCURRENCE. 



Borders of streams, water-holes, and lakes, in damp, gravelly, and sandy soil. Scat- 

 tered in small groups and singly ; sometimes with red and white alders, black and 

 Fremont cottonwoods, and California sycamore. Climatic and other requirements unde- 

 termined. 



A well-marked variety of this willow is the Lyall willow {Salix lasiandra 

 lyallii* Sargent), often from 20 to 30 inches in diameter; common on streams 

 of western Oregon and Washington. Its leaves (fig. 90) are sometimes 10 or 12 

 inches long, and distinctly white beneath, while the leaf stems have more 

 glands than those of the Western black willow. Another less distinct form is 

 SalLr lasiandra caudata (Nutt) Sudworth. which has smaller, more leathery 

 leaves than the species: they are also often scythe-shaped, tapering at the 

 base, and green throughout. 



Salix lasiandra lyalUi occurs in western Oregon, Washington, and southern British 

 Columbia at middle elevations. It grows on borders and bottoms of lowland streams and 

 Of those on lower mountain slopes. In moist, loamy sand and gravel or humous, rocky, and 

 gravelly soils of higher sites. Forms clusters in open pure stretches and patches, oi- 

 ls scattered singly at higher levels among other inhabitants of stream banks. Appears 

 Indifferent to altitude, but abundant soil moisture is a requisite. 



Climatic Conditions similar to those of red alder. 



Tolerance. — Endures considerable shade — probably one of the most tolerant of willows. 



Reproduction. — Abundant seeder ; seedlings rather scattered, but frequent. 



° Described in 1842 by Nuttall as Salix speciosa, from its large handsome leaves ; a 

 name which, nnknown to that author, was unfortunately already assigned to another 

 willow 



