WILLOW FAMILY 



345 



entire, scantily pilose, ^ to 1 or 1% inches long, 2 to 5 lines broad; catkins 

 on erect leafy peduncles, densely flowered, % to % inch long, the pistillate 1 

 to 2 inches long; peduncles in fruit 1 to 2 inches long; style long, stigmas 

 2-cleft ; capsules white woolly or glabrescent and brown, subsessile, 2 to 3 lines 

 long. 



Sierra Nevada, 9,000 to 11,000 feet: Mt. Whitney (southernmost locality), 

 Mt. Brewer, Mt. Goddard, Mt. Lyell, Mt. Dana, and other high peaks and 

 far northward to the Arctic Circle. 



Refs. SALIX TENERA Andersson in DeCandolle, Prodromus, vol. 16, pt. 2, p. 288 (1868), the 

 type from the Cascade Mts., lat. 49, 7,000 feet, Lyall. S. arctica Pallas var. petraea And. 

 1. c. p. 287. S. petrophila Rydberg, Bull. N. Y. Bot. Gard. vol. 1, p. 268 (1899). 



2. POPULUS L. POPLAR. 



Trees with scaly buds and caducous stipules. Leaves rather long-petioled, 

 broad. Winter buds covered by many scales. Catkins appearing before the 

 leaves, in ours pendulous; scales imbricate or lacerate, falling as soon as re- 

 leased by the flowering elongation of the catkin. Stamens inserted on the 

 surface of a concave disk. Ovary seated on a collar-like disk; style short; stig- 

 mas 2 to 4. narrow and elongated, or conspicuously dilated. Capsule 2 to 

 4-valved. Coma of the small seeds long and conspicuous. North temperate 

 zone, 18 species. (Classical Latin name of the Poplar.) 



Stamens 40 to 80. 



Leaves deltoid-orbicular, broader than long, yellowish green, alike on both faces; valley 



streams 1. P. fremontii. 



Leaves longer than broad, ovate, dark green above, rusty or silvery beneath; valley and 



mountain streams 2. P. trichocarpa. 



Stamens 6 to 12; leaves round-ovate, 1 to 2 inches long; high mountains. .3. P. tremuloides. 



1. P. fremontii Wats. COMMON COTTONWOOD. Handsome tree commonly 

 40 to 90 feet high with massive crown, the trunk 1 to 5 feet in diameter ; bark 

 white or whitish, on the main trunk 1 to 5 inches thick, roughly cracked ; 

 leaves triangular or roundish in outline, 2 to 4 inches broad, broader than 

 long, the margin crenate except at the abruptly short-pointed apex and the 

 truncate or subcordate base; scales regularly laciniate-f ringed, shorter than 

 the flowers: staminate catkins 2 to 4 inches long, densely flowered, each 

 flower with 48 to 72 stamens; pistillate catkins 2 inches long (becoming twice 

 as long in fruit), loosely flowered; ovary sinuously and strongly ridged about 

 its middle and surmounted by 3 or 4 roundish stigmas; mature pods ovate, 

 roughish on the surface, 4 to 5 lines long, borne on pedicels 2 lines long, 

 opening by 3 or 4 valves; seeds copiously provided with long white hairs 

 which soon involve the catkin in a soft cottony mass. 



Valleys and foothills, usually along living streams : common in the Sacra- 

 mento Valley from near Redding southward through the San Joaquin Valley, 

 lower Sierra Nevada foothills and South Coast Ranges to Southern California 

 and Mexico and far eastward to southern Colorado. Shunning the Redwood 

 Belt and very rare in the North Coast Ranges where thus far noted only at 

 the following localities: near Round Valley; fork of Eel River in northern 

 Lake Co. ; Russian River from Cloverdale to Ukiah. Not seen in Napa Valley 

 nor in the valley of San Francisco Bay from San Rafael and San Pablo to 

 Decoto. Most abundant and of greatest size on the Kaweah Delta. Valuable 

 shade and roadside tree in hot interior valleys. Also called Fremont Cotton- 

 wood. 



Refs. POPULUS FREMONTII Watson, Proc. Am. Acad. vol. 10, p. 350 (1875), type loe. Deer 



