Tree usually 70—100 feet high with a tapering trunk 2—5 feet in diameter and gracefully pendent slender branches and drooping lateral ones; bark grayish and scaly, on mature trees 1—1½ inches thick divided into rounded ridges with closely appressed cinnamon scales; leaves more or less in clusters, standing out all over the sides of the branches, rounded, light bluish-green or in some pale blue ½—1 inch long; cones sessile, cylindric, oblong, narrowed toward the blunt apex and somewhat toward the base, pendulous, 1—3 inches long, with thin scales usually as broad as long, with slightly thickened or erose margins, purplish-brown, 4 times as long as the sharp, purple bract. On the slopes and exposed ridges through the Selkirks, a most attractive tree. [Illustration: Tsuga Mertensiana (Bong.) Carr. (⅔ Nat.) Mountain Hemlock.] [Illustration: Tsuga heterophylla (Raf.) Sarg. (⅙ Nat.) Hemlock.] [Sidenote: =Picea Albertiana= S. Brown. _Alberta Spruce._] A tree 30—60 feet high, slender, strict; twigs smooth and shining or occasionally glandular, hairy, but never glaucous, yellowish-brown when young becoming darker with age, leaf bases long and standing out at right angles from the stem; leaves pale blue or blue-green, ½—1 inch long, nearly straight or curved, acute or with a rigid tip, 4-sided; cones ovate or oblong, bright crimson when young, at maturity 1—1½ inches long and nearly as broad when expanded, scales stiff and rigid, broadly rounded at the apex, entire, broader than long, cinnamon brown with a chestnut edging; bract very small with a sharply angular tip. The common spruce in the lower valleys and river bottoms throughout the Rockies. [Sidenote: =Picea Engelmanni= (Parry) Engelm. _Engelmann’s Spruce._] A tree often 150 feet high but usually much lower, with a trunk reaching 4—5 feet in diameter; spreading branches, produced in regular whorls and forming a narrow compact pyramidal head, and gracefully hanging short lateral branches; bark when mature reddish-brown and broken into thin scales; leaves soft and flexible, slender or slightly incurved, stouter on the fertile branches, ½—1⅛ inches long, glaucous when young, becoming dark blue-green; cones oblong-cylindric, 1—2 inches long, lustrous, light chestnut brown with thin flexible wedge-shaped scales, with erosedentate margins. On the higher mountain slopes in the Rockies, but much lower in the valleys of the Selkirks, where it grows to a great size. [Sidenote: =Juniperus Siberica= Burgs. _Alpine Juniper._]