SALICACEAE (WILLOW FAMILY) 135 



VII. LANATAE. Mostly shrubs 1-4 m. high; twigs stout, divaricate, tomen- 

 tose: leaves large, broadly elliptical to obovate-oval or suborbicular, more or 

 less tomentose: aments very large, stout and dense, sessile or short-peduncled, 

 3-8 cm. long, lateral or terminal: capsules large, sessile or subsessile, glabrous 

 (in our species) or tomentose; styles much elongated. Only one species cer- 

 tainly within our limits. 



19. Salix Tweedyi (Bebb) Ball, Bot. Gaz. 40: 377. 1905. Low (?) shrub; 

 the youngest twigs more or less tomentose with long hairs: leaves broadly 

 elliptical to oval or ovate, acute or obtuse at both ends to rounded or cordate 

 at the base, 5-7 cm. long, 2-4 cm. wide, green above, paler but not glaucous 

 beneath, glabrous throughout or sparsely gray-tomentose above, finely 

 glandular-denticulate or mature leaves irregularly spinulose-denticulate ; 

 petioles tomentose, 8-15 mm. long; stipules large, clasping, broadly reniform, 

 glandular-denticulate: aments precocious, the pistillate sessile, 4-6 cm. long, 

 1.5 cm. or more wide; scales obovate, black, clothed with long white hairs: cap- 

 sule large, green, glabrous or finely pubescent at the apex, 7-8 mm. long; 

 pedicels 1 mm. long; styles 1.5-2.5 mm. long; stigmas divided; gland 1 mm. 

 long. (S. Barrattiana Tweedyi Bebb, Contrib. U. S. Nat. Herb. 3:572. 1896.) 

 In bogs and along mountain streams, 2,500-3,000 m. altitude, not common; 

 known only from the Big Horn Mountains of northern Wyoming, the Yellow- 

 stone Park, and Teton Basin. 



VIII. ARCTICAE. Low, erect, or creeping alpine shrubs, 1-10 or 15 dm. high; 

 branches full of leaf-scars: leaves small to medium, narrowly elliptic or ob- 

 lanceolate, occasionally broader, entire, more or less tomentose; stipules small 

 or none: aments appearing with the leaves, on short, leafy peduncles; scales 

 brown, brown-tipped, villous: capsules sessile or short-pediceled, gray- or 

 white-tomentose; styles 1-1.5 mm. long; stigmas medium, notched. 



Erect or spreading subalpine shrubs 2-15 dm. high. 



Capsules and leaves gray- or yellowish-tomentose or leaves glabrate. 

 Aments much longer than broad; leaves gray-tomentose, drying 



black 20. S. glaucops. 



Aments subglobose, leaves yellowish-tomentose beneath, not 



drying black . . . . . . . . . 21. S. brachycarpa. 



Capsules and lower leaf-surfaces densely white-tomentose . . 22. S. Candida. 

 Depressed, creeping alpine plants, less than 1 dm. high. 



Leaves broadly elliptical to obovate, pale beneath, 2-4 cm. long . 23. S. petrophila. 

 Leaves narrowly elliptical or obovate, scarcely 10-12 mm. long . 24. S. tenera. 



20. Salix glaucops Anders. DC. Prodr. 162; 281. 1868. Subalpine shrub, 

 4-15 dm. high; branches and twigs short and stout, shining, chestnut-brown 

 or darker, the bark separating from the older branchlets in thin gray papery 

 flakes: leaves elliptic-lanceolate, or oblanceolate to oblong-ovate, entire, 

 obtuse or subacute at the apex, obtusish to subcordate at the base, 3-5 or 

 6 cm. long, 1-1.7 or 2 cm. wide, gray-tomentose or glabrate on both sides, 

 dark green above, glaucous and reticulate beneath; petioles yellowish, 5-10 

 mm. long; stipules minute, ovate or semicordate: peduncles 2-3 cm. long, 

 tomentose; staminate aments 1-3 cm. long, 1-1.5 cm. wide; pistillate 3-5 cm. 

 long and 1.5 cm. wide; scales oblong, dark to pale brown, villous: capsules 

 conic, gray-tomentose, 6-7 or 8 mm. long; pedicels stout, pubescent, 1-1.5 mm. 

 long; styles fuscous or yellowish, 0.7-1 mm. long. (S. pseudolapponum v. 

 Seem. Engl. Jahrb. XXIX, Beibl. 65: 28. 1900; S. Seemannii Rydb. Bull. N. Y. 

 Bot. Gard. 2: 164. 1901; S. wyomingensis Rydb. Bull. Torr. Bot. Club 28: 271. 

 1901.) Common in boggy places at middle to high elevations; New Mexico 

 to Canada and westward. 



20a. Salix glaucops glabrescens Anders. Leaves more rigid, glabrate, 

 intensely glaucous beneath: aments stouter, capsules sometimes glabrescent. 

 Range of the species but less common. 



21. Salix brachycarpa Nutt. N. Am. Sylva 1: 69. 1842. A small alpine 

 shrub, scarcely more than 1 m. high; branches stoutish and divaricate 

 within our limits, longer and more slender northward, reddish-brown to 

 yellowish or gray; twigs tomentose: leaves elliptical-oblong or oblanceolate 



