Populus angustifolia, commonly known as the narrowleaf cottonwood, is a species of tree in the willow family (Salicaceae). It is native to western North America, where it is a characteristic species of the Rocky Mountains and the surrounding plains.[1] It ranges north to the provinces of Alberta and Saskatchewan in Canada and south to the states of Chihuahua, Coahuila, and Sonora in Mexico.[1] Its natural habitat is by streams and creeks between 1200to elevation.[1]
The tree is slim in profile, and can grow in tightly packed clusters.[2] Its leaves are yellow-green, lanceolate (lance-shaped), and with scalloped margins. It produces catkins in the early spring. The fruiting capsules are fluffy and white.
Where their ranges come into contact, this species will readily hybridize with Populus balsamifera, Populus deltoides, Populus fremontii, and Populus trichocarpa. These hybrids can form extensive populations in some regions. Due to the frequency and morphological consistency of P. angustifolia × P. deltoides hybrids, they were initially described as a fully separate species ("P. acuminata") until its hybrid origin was firmly established in the 1980s.[1]
The buds are sticky and gummy and were enjoyed as a sort of chewing gum by local Native American peoples, including the Apache and Navajo. The tree is the host species of the sugarbeet root aphid (Pemphigus betae).