General:
Dioecious shrubs or trees, 0.5-6 m tall, forming colonies by root shoots, branches erect, flexible at base; twigs yellow- to red-brown, smooth or sparsely to densely hairy.

Leaves:
Alternate, simple, linear to strap-shaped, 3-16 cm long, 0.2-1 cm wide; lower surface glaucous or not, silky or long-soft hairy to nearly smooth, hairs white, upper surface shiny, silky or long soft-hairy to nearly smooth, margins entire or remotely and minutely spiny-toothed, bases wedge-shaped, tips pointed to tapered; leaf stalks without glandular dots at top; stipules leaflike, rudimentary or absent.

Flowers:
Unisexual, lacking sepals and petals, borne in catkins which flower as leaves emerge or throughout season, the catkins slender on leafy twigs, floral bracts pale, hairs wavy or straight, female bracts deciduous; stamens 2; ovaries 1, smooth or hairy; styles 0-0.2 mm long.

Fruits:
Capsules which split open to release the seeds, each of which is surrounded by a tuft of hairs; stalks 0.2-0.9 mm long.

Source:  The Illustrated Flora of British Columbia