SALICACEAE. 309 



faceme-like, peduncled ; capsules ovoid, acute, 2-valved, 8-12 mm. long, shorter 

 than or equalling their pedicels. In swamps, S. Conn, and N. Y. to Ga., west to 

 La., north in the Miss. Valley to Ind. and Ark. April-May. 



3. Populus candicans Ait. BALM OF GILEAD. A large tree, reaching a height 

 of 30 m. and a trunk diameter of 2 m., with spreading branches; the buds large 

 and very resinous. Leaves broadly cordate, dark green above, pale beneath, 

 acuminate, more coarsely crenate than in the next with gland-tipped teeth, 6-15 

 cm. long, 3-12 cm. wide, pubescent when young, generally glabrous in age, with 

 the exception of the ciliate margins and pubescent veins and petioles; otherwise 

 like the following. N. B. to N. J. west to Minn., but mostly escaped from culti- 

 vation. (P. balsamifera candicans A'. Gray.) 



4. Populus balsamifera L. TACAMAHAC. BALSAM POPLAR. (I. F. f. 1165.) 

 A large tree, with nearly smooth gray bark, reaching a maximum height of about 

 25 m. and a trunk diameter of 2 m., the branches stout, ascending, the large buds 

 very resinous, the foliage glabrous. Leaves broadly ovate, dark green and shining 

 above, pale l>eneath, acute or acuminate at the apex, rounded or acute at the base, 

 crenulate, 7-12 cm. long; aments and bracts somewhat pubescent; stamens 18-30; 

 lobes of the stigmas broad; capsule ovoid, 2-valved, short-pedicelled. In moist or 

 dry soil, especially along streams and lakes, Newf. to Hudson Bay and Alaska, 

 south to N. Y., Neb. and Nev. April. 



5. Populus angustifolia James. NARROW-LEAVED OR BLACK COTTONWOOD. 

 (I. F. f. 1166. ) A slender tree, maximum height about IQ m., trunk diameter 6 dm. ; 

 crown narrowly pyramidal, branches ascending; foliage glabrous. Twigs terete, 

 gray; leaves lanceolate, ovate-lanceolate or ovate, spreading, drying brownish, 

 gradually acuminate or acute at the apex or some of them obtuse, narrowed, 

 rounded or rarely subcordate at the base, 5-12 cm. long, 1-3 cm. wide, finely cren- 

 ulate from base to apex; petioles plano-convex, not flattened laterally, 612 mm. 

 long; lateral veins 8-15 on each side of the blade; staminate aments oblong-cvlin- 

 dric, 2-6 cm. long; lobes of the stigmas broad; capsules ovoid, short-pedicelled. 

 In moist soil, especially along streams, N. W. Terr, to Neb., N. Mex., and Ariz. 

 April-May. 



6. Populus acuminata Rydberg. RYDBERG'S COTTONWOOD. (I. F. f. 1167.) 

 A slender tree, with terete twigs, reaching approximately the dimensions of P. 

 angustifolia, the crown broadly pyramidal with spreading branches, the foliage 

 glabrous. Leaves rhomboid- lanceolate, spreading or drooping, drying green, 

 abruptly or gradually long-acuminate at the apex, cuneate, obtuse or rounded at 

 the base, 5-15 cm. long, 2-6 cm. wide, crenulate or the base entire; petioles slen- 

 der, 26 cm. long; staminate aments about 3 cm. long; pistillate aments slender, 

 drooping, 7-12 cm. long; capsules ovoid, obtuse, distinctly pedicelled. Black Hills, 

 S. Dak. to Utah, south to N. Mex. April-May. 



7. Populus nigra L. BLACK POPLAR. (I. F. f. 1171.) A large tree, some- 

 times 30 m. tall and the trunk 12 dm. in diameter, usually much smaller. Twigs 

 terete; young foliage somewhat pubescent, the mature leaves firm, nearly or quite 

 glabrous; petioles slender, flattened laterally; leaves broadly deltoid, abruptly 

 acuminate at the apex, broadly cuneate or obtuse at the base, crenate, 5-10 cm. 

 long; staminate aments 3-5 cm. long; stamens about 20; pistillate aments 5-12 

 cm. long in fruit, spreading; capsules oblong, very obtuse, borne on pedicels of 

 much less than their own length. Valleys of the Hudson and Delaware Rivers, 

 naturalized from Europe. April-May. 



The Lombardy Poplar, Populus Italica, commonly planted for ornament, occa- 

 sionally spreads by sending up shoots from its subterranean parts. 



8. Populus deltoides Marsh. COTTONWOOD. NECKLACE POPLAR. (I. F. f. 

 1172.) A large tree, the greatest of the poplars, attaining a maximum height of 

 45 m. and a trunk diameter of 2.2 m., the bark grayish-green, somewhat rough 

 when old. Foliage glabrous; leaves broadly deltoid-ovate, abruptly acuminate at 

 the apex, crenulate, truncate at the base, 10-17 cm - lon g; petiole flattened later- 

 ally, stout, about as long as the blade; bracts glabrous, deeply fimbriate; staminate 

 aments drooping, 7-12 cm. long, 10-12 mm. in diameter; pistillate aments loosely 



