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Alpine flora of the Canadian Rocky Mountains

Chapter 15: Salicaceæ Willow Family
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About This Book

A concise field manual that surveys the alpine and subalpine plants encountered along the Canadian Rockies and the Selkirks accessible by the trans-mountain railway, emphasizing distinct regional assemblages and plant adaptations to differences in moisture and exposure. Species are arranged by botanical families with general keys to families and genera; treatments include ferns, conifers, shrubs and the majority of herbaceous flowering plants while excluding grasses, sedges, and willows. Descriptions are accompanied by plates, watercolour illustrations and photographs, and the text relates local taxa to comparable mountain floras while noting characteristic species, habitats and elevational ranges.

Salicaceæ
Willow Family

Trees or shrubs with light wood, brittle twigs, and simple alternate leaves; flowers borne in catkins; the staminate and pistillate on separate plants, the seed provided with a covering of long, white, silky, hairs.

Populus balsamifera L. Balsam Poplar.

A large tree with nearly smooth gray bark, reaching a maximum height of 80 feet; branches stout, ascending, the larger buds very resinous. Leaves smooth, broadly ovate or ovate-lanceolate, entire, dark green and shining above, pale beneath, acute or acuminate at the apex, rounded or acute at the base, petioles round. Flowers in slender catkins, the staminate and pistillate on separate trees.

Throughout the region in the river valleys and on the surrounding slopes, usually a tree not over 20—30 feet high but sometimes attaining an immense size.

Populus tremuloides Michx. American Aspen.

A slender tree with smooth, light green bark, seldom more than 40—50 feet high, and less than half that in our region. Leaves smooth when young except on the margins, ovate, short-acuminate at the apex, rounded at the base, finely crenulate all around; petioles flattened laterally, very slender, causing the leaves to quiver with the slightest breeze. Flowers in rather stout catkins.

Frequent in the low valleys and slopes through the Rockies, forming groves, or singly.

The willows which are very largely represented throughout the region, in the low or moist ground and banks of streams, as shrubs or small trees; or on the drier slopes, and in alpine meadows and summits, frequently as very diminutive shrubs with stems less than an inch high, have been omitted entirely, owing to the extreme difficulty of distinguishing between them in a work of this kind.