SALFCACEJE. 



351 



15. S. GHl'SEA. 



Lciircs lanceolate, serrulate, acuminate, smooth above, silky beneath; 

 stipules ovate-oblong, denticulate, deflected, deciduous; scahs oblong, lairy, 

 blackat the tip; vvaries oblong, pedicellate, silky ; 5«/£-wtf5 sessile, obtuse. 

 A shrub G— 8 feet high, in inundated meadows. Branches purple, brittle at 

 base. Leaves 2-4 inches long, i as wide. April. Gray WiLLovs. 



2. PO'PULUS. 



Ament cylinclric ; bracls lasciniate-fringcc] ; scales lurbi- 

 nate, eiiiiie, oblique. Slerile. /?.— SianvMis 8—20, seated on 

 the scale. Ferlile f.—Siv^nr^s 4-c\eh ; capsule supe.ior, 

 2-celled. 



Lat. povvhis, the people. In ancient times the public walks at Rome were 

 decorated with rows of P.dlhitata ; whence it was called arbor popv 1 1 Some 

 suppose, however, it is so called on account of its leaves, which are in per- 

 petual agitation like the populace. 



1. P. tremuloi'des. 



Leares orbicular-cnrdate. abruptly acuminate, dentate-serrate, pubescent at 

 the maroin. Abundant inN. Enojand and in the Rliddle States, growing m 

 woods and open lands. Stem 2.")— 40 feet in hisrht,with a diameter of b— 12 

 inches Bark greenish, smooth e.xcept on the trunk of the oldest trees. 

 Leaves "mail (2—24 inches long, and ]} as wide), dark green, on petioles 

 which are 2—3 inches long and laterallv compressed, so that they can scarcely 

 remain at rest in any position, and are" thrown into excessive agitation by t.ie 

 slio-htest breeze. The trembling of the '• aspen leaf" is proverbir,l. Aments 

 plumed with silken hairs, about 2 inches long, pendulous, appearing m April, 

 iono- belbre the leaves. The wood is white, soft and light, of little value. 

 ° American dspcn. lliiUc Pujilar. 



2. P. grandidenta't.^. 



Leflr« roundish-ovate, acute, with large, unequal, sinuate teeth, smootli, 

 villous when young. Woods and groves^in the northern parts of the U. b., 

 less common than the preceding species. Stein 40 feet high, with a diameter 

 of 1 foot, straioht, covered with a smooth, greenish bark. Branches ihstant, 

 coarse and crSoked, clothed with leaves only at their extremities. Leaves 

 S— .5 inches long and nearly as wide, clothed with thick, white down in 

 sprino-, but becoming perfectly smooth. The wood is white, soft, and quite 

 durable. May. Large American .Isjwn or Poplar. 



3. P. BETULIFO'LIA. P. P- Hudsonica. Mx. 

 Lcnvrs rhomboidal. long-acuminate, dentate, smooth ; young hrnnrJics pilose. 



This poplar is found chiefly in the vallies of the Hudson and Connecticut. 

 It is a tree of middle size, with grayish white twigs and dark brovi'n buds. 

 Leaves ^ inches long and 2 broad. Aments 4—5 inches long, without 

 hairs. A'pnl. Birch-lcuf Poplar. 



4. P. balsami'fera. 



Leaves ovate-acuminate, with close-pressed serratures, white and reticulate- 

 veined beneath; huds resinous. The balsam poplar, though nowhere 

 abundant, is found in woods and fields, disseminated throughout^ N. England 

 and Canada. With a trunk 18 inches in diameter it arises GO— 70 feet. The 

 buds of this species, as well as of most of the poplars, are covered with ail 

 aromatic resin, which may be separated in boiling water. Apr. Balsam Poplar. 



