E-Flora BC: Electronic Atlas of the Flora of British Columbia

General:
Deciduous tree, 10-30 m tall; bark white, yellowish- to reddish-brown or dark grey, often peeling; twigs hairy with both short and long hairs.

Leaves:
Alternate, deciduous, broadly egg-shaped in outline, the tips sharp-pointed, hairy below, rarely glandular, 4-10 cm long, leaf stalks more than 1 cm long.

Flowers:
Male and female flowers in separate catkins 2-4 cm long; flowers emerging before or with the leaves; catkins breaking up at maturity.

Fruits:
Nutlets with broad wings, at least twice as wide as the body of the nutlets; bracts with rounded, ascending or diverging lateral lobes.

Notes:
Numerous apparent hybrids between B. papyrifera and B. neoalaskana or B. occidentalis (e.g., B. x utahensis Britt. and B. subcordata Rydb.) have been formally named (see Brayshaw 1996b, Scoggan 1979). Two varieties occur in BC.

1. Mature bark white; fruiting bracts with ascending lateral lobes............... var. papyrifera

1. Mature bark white, yellowish- to reddish-brown or dark grey; fruiting bracts with lateral lobes diverging at right angles................... var. commutata (Regel) Fern.