:U6 SALICACEAE 



Creek, Tehama Co., Fremont; Havard, Gard. & For. vol. 3, p. 620 (1890); Merriam, N. Am. 

 Fauna, uo. 7, p. SS.t (1S93) ; Jepson, Fl. W. Mid. Cal. p. 138 (1901). 



2. P. trichocarpa T. & G. Black Cottonwood. Tree commonly 30 to 125 

 feet high, with a broad head of upright branche.s ; trunk 1 to 3 feet in diameter ; 

 bark light or dark in color but usually with a yellowish cast, longitudinally 

 fissured, the long, narrow and rather smooth-surfaced plates separated by 

 cleanly channeled fissures; leaves broadly or narrowly ovate, finely serrate, 

 truncate or heart-shaped at base, acute or tapering to a point at apex, 2i/4 

 to 7 (or 11) inches long, lustrous green above, rusty -brown beneath when young 

 but at length whitish; staminate catkins 1 to 2 or eventually 5 inches Lmg. 

 each flower with 40 to 60 stamens on a slightly one-sided disk; anthers light 

 purple ; pistillate catkins loosely flowered. 2i/i> to 3 inches long and 4 to 10 

 inches long in fruit ; ovary crowned by 3 dilated and deeply lobed stigmas ; 

 pod nearly sessile, 3-valved ; seeds with long lustrous white hairs. 



Living streams in canons and valleys : Sierra Nevada, 3,000 to 8.000 feet, 

 common along streams and on such canon floors as Kern, Kings and Yosemite ; 

 South Coast Ranges in the Mt. Diablo, Mt. Hamilton, Santa Cruz and Santa 

 Lucia ranges and southward to the San Bernardino and San Jacinto mts., the 

 most southerly locality on Palomar at Cootea (San Diego Co.); North Coast 

 Ranges from northern Lake Co. westerly to Long Valley and Petrolia, and 

 northward to Trinity Summit, Salmon, Shasta and Klamath rivers ; far north- 

 ward to Alaska. Most abundant on the Oregon and "Washington coasts where 

 it is lumbered for staves and woodenware. It is the tallest species in the 

 genus. Winter buds covered with a balsam resin wherefore also called "Balm" 

 and "Balsam Cottonwood." 



Var. cupulata Wats. Disk campanulate, pubescent, twice longer than ovary. 

 — Plumas Co.. according to Bot. Cal., vol. 2, p. 91. 



Forma ingrata Jepson n. form. Leaves lanceolate, 2 to i^U inches long, 4 to 

 10 lines broad. — (Folia varia valde, lanceolata in typo, 2 ad 4I/2 poll, longa, 4 

 ad 10 lin. lata). — San Bernardino I\Its., upper Santa Ana Caiion, mouth of north 

 fork, H. il. Hall, no. 7517. A singular type but connected with the usual form 

 by several transition states. 



Refs. — PoPULUs TRiCHOC.iRPA T. & G. in Hooker, Icon. vol. 9, pi. 878 (18.52), type loc. Santa 

 Clara River, Ventura Co., C. C. Parry; Jepson, Fl. W. Mid. Cal. p. 138 (1901). 



3. P. tremuloides jMiehx. Aspen. Slender tree with branches gracefidly 

 pendulous towards the ends, 10 to 60 feet high, the trunk 3 to 10 inches in 

 diameter, bark smooth, greenish white, or on old trunks nearly black; leaves 

 round-ovate, finely toothed or almost entire, abruptly tipped at apex with a 

 short sharp point, 1 to 2 inches long; staminate catkins li/o to 'lyo inches 

 long, each flower with 6 to 12 stamens ; pistillate catkins 2 to 4 inches long ; 

 ovary conical; stigmas 2, very thick below, divided above into 2 slender 

 spreading lobes; style short and thick; seeds minute, brownish, bearing long 

 white hairs. 



Sierra Nevada, margins of streams or swampy meadows or on rocky drifts, 

 5.000 to 10,000 feet : Kern Canon ; Mineral King ; Giant Forest ; Bubbs Creek ; 

 North Fork Kings River; South Fork San Joaquin; Yosemite National Park 

 and frequent northward to Donner and ]\Iodoc Co. Not known on ^Mt. Shasta 

 and locally noted elsewhere in the State only in the Trinity :Mts. (Canon 

 Creek) and San Bernardino ilts. (Fish Creek Canon, San Gorgonio Peak, Jos. 

 Grinnell, the leaves less than 1 inch long and broader than long). Ranges 



