Trees with scaly resinous buds, terete or angled twigs and broad or narrow, usually long-petioled leaves, the stipules minute, fugacious. Bracts of the aments fimbriate or incised. Disk cup-shaped, oblique, lobed or entire. Staminate aments dense, pendulous. Staminate flowers with from 4-60 stamens, their filaments distinct. Pistillate aments sometimes like through the elongation of the pedicels, pendulous, erect or spreading. Ovary sessile; style short, stigmas 2-4, entire or 4-lobed. [Name ancient, used for these trees by Pliny.]

About 30 species, natives of the northern hemisphere. Besides the following, some 8 others occur in the western parts of North America. Type species: Populus alba L.

* Petioles terete or channeled, scarcely or not at all flattened laterally. (Poplars.)

Leaves persistently and densely white-tomentose beneath.


P. alba.

Leaves glabrous or very nearly so when mature, crenulate.

Foliage glabrous or nearly so; capsule very short-pedicelled.

Leaves broadly ovate, rounded or cordate at the base.

Petioles glabrous; leaves rounded or truncate at the base.


P. balsamifera.

Petioles ciliate; leaves mostly cordate.


P. candicans.

Leaves lanceolate or ovate-lanceolate, mostly narrowed at the base.

Leaves acute, short-petioled.


P. angustifolia.

Leaves acuminate, long-petioled.


P. acuminata.

Foliage densely tomentose when young; capsules slender-pedicelkd.


P. heterophylla.

** Petioles strongly flattened laterally. (Aspens.)

Leaves coarsely undulate-dentate.


P. grandidentata.

Leaves crenulate-denticulate.

Leaves ovate or suborbicular, short-pointed.


P. tremaloides.

Leaves broadly deltoid, abruptly acuminate.

Leaves obtuse at the base; capsules nearly sessile.


P. nigra.

Leaves truncate at the base; capsules slender-pedicelled.

Pedicels as long as the capsules or longer.


P. deltoides.

Pedicels shorter than the capsules.


P. Sargentii.