Populus x canescens (Aiton) Sm. (pro sp.) [alba × tremula]
Family: Salicaceae
[Populus alba var. canescens Aiton,  more...]
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Large tree 12 - 20 m tall

Leaves: alternate. The leaves on long shoots are dark green above, densely gray-hairy beneath, 6 - 12 cm long, triangular to egg-shaped with a slightly heart-shaped base, triangle-toothed, slightly wavy along the margins, and sometimes fringed with hairs. The teeth are gland-tipped. The leaves on short shoots are light green above, paler and hairless beneath, and rounded to oval-shaped with a rounded tip.

Flowers: either male or female, borne on separate trees (dioecious) in hairy-bracted catkins. Male catkin 6 - 10 cm long. Female catkin 2 - 3 cm long.

Fruit: a capsule borne in drooping catkins. Seeds have cottony hairs attached.

Bark: with diamond-shaped indentations (lenticels) on young trees, becoming deeply furrowed with age.

Form: spreading.

Similar species: Populus x canescens is very similar in appearance to its parent P. alba, but the leaves of P. alba are usually larger, more broadly toothed, and sometimes lobed. Since some leaves of P. x canescens can become smooth and hairless, they may resemble those of P. grandidentata, but with fewer teeth.

Flowering: late March to late April

Habitat and ecology: In the Chicago Region, Populus x canescens has been found growing along railroads and in degraded woods, presumably escapes from plantings.

Occurence in the Chicago region: non-native

Notes: Characteristics of Populus x canescens are very similar to P. alba. However, some authorities consider P. x canescens to be a hybrid between P. alba and the European P. tremula, and characteristics of both species may occur. Populus species as a whole are subject to many diseases and insect pests, such as canker and tent caterpillars, which often kill the tree or make it unattractive. These risks, in conjunction with a water-hungry root system, have made the Populus species less desirable for landscape use.

Etymology: Populus is the Latin word for poplar. Canescens means "with hairs of off-white or ashy-gray color."

Author: The Morton Arboretum

A hybrid of P. alba and the Eurasian aspen, P. tremula L. Occasionally planted and rarely escaped, it differs most obviously from P. alba in having the lvs merely coarsely toothed (none lobed), and glabrescent in age.

Gleason, Henry A. & Cronquist, Arthur J. 1991. Manual of vascular plants of northeastern United States and adjacent Canada. lxxv + 910 pp.

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