59 



SALICACEAE. 



VOL. I. 



. 8. Populus tremuloides Michx. Ameri- 

 can Aspen. Quiver-leaf. Fig. 1447. 



Populus tremuloides Michx. Fl. Bor. Am. 2 : 243. 1803. 



A slender tree, with smooth, light green bark, 

 reaching a maximum height of about 100 and a 

 trunk diameter of 3, the young foliage glabrous, 

 excepting the ciliate margins of the leaves. Petioles 

 very slender, flattened laterally, causing the leaves to 

 quiver in the slightest breeze ; leaves broadly ovate 

 or orbicular, short-acuminate at the apex, finely 

 crenulate all around, truncate, rounded or subcordate 

 at base, i'-2i' broad, or those of very young plants 

 much larger; bracts silky, deeply 3~5-cleft into linear 

 lobes; aments drooping, the staminate ii'-2i' long, 

 3 "-4" in diameter, the pistillate longer, dense ; stigma- 

 lobes linear ; capsule like that of the preceding species, 

 but somewhat smaller. 



In dry or moist soil, Newfoundland to Hudson Bay and 

 Alaska, New Jersey, Pennsylvania, Kentucky, Nebraska, 

 in the Rocky Mountains to Mexico and to Lower Cali- 

 fornia. Ascends to 3000 ft. in the Adirondacks. American, trembling or white poplar. Quaking 

 or mountain asp. Wood soft, weak, light brown ; weight per cubic foot 25 Ibs. March-May. 



g. Populus nigra L. Black Poplar. Willow 

 Poplar. Fig. 1448. 



Populus nigra L. Sp. PI. 1034. 1753. 



A large tree, sometimes 100 tall and the trunk 4 

 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, 2' -4' long; staminate aments i'-2' 

 long; stamens about 20; pistillate aments 2' -5' 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, natural- 

 ized from Europe. Cat-foot poplar. Devil's-fingers. 

 Old English poplar. April-May. 



The Lombardy poplar (Populus italica Moench (Pop- 

 ulus dilatata Ait.), commonly planted for ornament, occa- 

 sionally spreads by sending up shoots from its subterra- 

 nean parts. Poplar-pine. 



4 n 



10. Populus deltoides Marsh. Cottonwood. 

 Necklace Poplar. Fig. 1449. 



Populus deltoides Marsh, Arb. Am. 106. 1785. 

 Populus carolincnsis Moench, Verz. PL 81. 1785. 

 Populus monilifera Ait. Hort. Kew. 3: 406. 1789. 

 Populus angnlata Ait. Hort. Kew. 3: 407. 1789. 



A large tree, the greatest of the poplars, attain- 

 ing a maximum height of 150 and a trunk diam- 

 eter of 72, the bark grayish-green somewhat rough 

 when old. Foliage glabrous; leaves broadly deltoid- 

 ovate, abruptly acuminate at the apex, crenulate, 

 truncate at the base, 4' -7' long; petiole flattened 

 laterally, stout, about as long as the blade; bracts 

 glabrous, deeply fimbriate; staminate aments droop- 

 ing, 3 '-5' long, 5"-6" in diameter; pistillate aments 

 loosely flowered, becoming 6'-io' long in fruit ; cap- 

 sules ovoid, acute, 4"-$" long, 2-4-valved, shorter 

 than or equalling their pedicels. 



In moist soil, especially along streams and lakes, Que- 

 bec to Manitoba, south to Connecticut, Florida and Ten- 

 nessee. Wood soft, weak, dark brown ; weight per cubic 

 foot 24 Ibs. April-May. Carolina poplar. Water- or 



river-poplar. Berry-bearing, or black Italian poplar. Big or yellow cottonwood. Cotton-tree. 



Alamo. The species consists of several races. 



