Name

Pinus flexilis E.James, Account Exped. Pittsburgh 2: 27, 35 (1823).
[Rocky Mountain white pine, Limber pine, Flexilis pine]

Description

Habit: Small to medium tree, about 10-25 m tall. Trunk strongly tapered, often divided into several stems especially in older trees; crown conical at first, becoming rounded, branches sometimes persistent to trunk base, often drooping.

Bark: Thin, smooth and grey on young trees, later becoming dark brown and fissured into scaly plates and ridges.

Foliage: Needles in 5s, crowded near branchlet ends, 3-9 cm x 1-1.5 mm, dark green or blue-green, rigid, curved or slightly twisted, usually without serrated edges, stomata more conspicuous on inner sides than outer side, sharply pointed, persisting for 5 or 6 years.

Branchlets: Very pliant, pale green when young, covered with minute brownish hairs or sometimes hairless, slightly resinous, becoming grey-brown.

Winter buds: Ovoid to cylindric, sharply pointed, light red-brown, scale tips appressed or free, resinous.

Cones: Almost stalkless, cylindric-ovoid, 7-25 cm long, 4-8 cm wide when open, yellow-brown to grey-brown, clots of white resin on scales, upper margins of scales thickened and often slightly reflexed, especially on the lower part of the cone, scales at base of cone strongly reflexed.

Seeds: Ovoid, large, 8-15 mm long, reddish brown, sometimes mottled, nearly wingless with wing reduced to a rim about 1mm wide.

Notes

Distinguished from other 5-needled pines by the combination of shortish, stiff, dark green needles held closely in their bundles, needles usually without serrations, lustrous, often yellow-brown cones and almost wingless seeds. Superficially resembles foxtail pines but has bare shoot amongst needles, no rosette at base of needles, and cone scales without prickles.

Natural Distribution

Western North America.