AMENTACE^E. 323 



ed ; petioles hairy ; buds resinous ; branches terete. P. canadcrisis 

 and latifolia Moench. 



HAB. Woods. N. Eng. Pursh. March. f?. A tree from 

 4050 feet high ; leaves large ; buds covered with balsam. 



Balm of Gilead. 



3. P. trcmuloides Mich. : leaves roundish, abruptly acuminate, den- 

 tate-serrate, pubescent on the margin. P. trepida Willd. ? 



HAB. Woods. N. S. N. to Subarc. Amer. April. T?. A 

 tree from 20 30 feet high, with smooth bark. Leaves small, 

 light, roundish. Flowers in pendulous silken aments. 



4. P. monili/era Ait. : leaves subcordate-deltoid, smooth, glandular 

 at base, serrate ; serratures cartilaginous, hamate, somewhat hairy ; 

 nerves spreading ; petioles compressed above ; older branches terete. 

 P. glandulosa and P. caroliniensis Moench. 



HAB. Banks of the Hudson, near Troy, N. Y. ; apparently native. 

 April. *>. A tree 7080 feet high. Fertile aments very long. 

 Michaux remarks that this tree has not been met with in N. 

 America growing wild, but it has been generally considered a 

 native of this country. Virginian Poplar. 



5. P. kudsonica Mich. : leaves rhomboid, with a very long acumina- 

 tion, dentate-serrate, smooth ; young branches hairy. P. betulifotia 

 Pursh. 



HAB. Banks of streams. N. S. March. T?. A tree 3040 

 feet high, with spreading branches, which are covered with a 

 grayish- white bark when youug. American Black Poplar. 



6. P. grandidentata Mich. : leaves ovate, nearly round, acute, unequal- 

 ly and sinuately toothed, smooth, the younger ones villous ; petioles 

 compressed near the summit. 



b. pendula Nutt. : branches pendulous. 



HAB. Can. and N. S. April. J?. A tree from 40 to 50 feet high, 

 covere<^lvith a smooth greenish hark. Young leaves covered with 

 a thick down, which disappears as they become older. The 

 large and unequal . indentations on the margins of the leaves 

 sufficiently characterises this species. Var b. is found on the 

 Alleghany mountains, Penn. American Large Aspen. 



7. P. lavigata Alt. : leaves roundish-ovate, deltoid, acuminate, sub- 

 cordate, unequally serrate, smooth, glandular at base ; petioles com- 

 pressed ; younger branches angled. P. canadensis Mich. 



. HAB. Rocky grounds. -Can. to Vir. W. to the Rocky Moun- 

 tains. March. *>. A tree from 70 to 80 feet high ; branches 

 angular, the angles forming whitish lines. Leaves large, deltoid, 

 somewhat cordate ; petioles with two glands at the base. This 

 species has been confounded with P. angulata, but according to 

 the younger Michaux it is distinct. Cotton Wood. 



8. P. heterophytta Linn. : leaves roundish-ovate, obtuse, uncinately 

 toothed; the sinus small, cordate and somewhat auricled; when young 

 tomentose. 



HAB. Swamps. N. Y. to Car. and W. to Miss. May. J?. 





