16 PINACEAE 



9. HESPEROPEUCE Lemmon. Black Hemlock, Mountain Hemlock. 



Monoecious evergreen trees with spreading branches. Leaves rather plump, 

 keeled beneath, spreading in all directions, articulated to persistent bases (sterig- 

 mata), with stomata on both sides. Staniinate aments axillary to leaves of pre- 

 ceding year; anther-sacs opening transversely. Pistillate aments terminal, at 

 first erect; scales in rather many series. Cones maturing the first year; scales 

 persistent. Seeds samara-like. 



1. H. Mertensiana (Bong.) Rydb. A tree usually 10-20 m. high, but some- 

 times uj) to 35 m. high, with a trunk 2.5-10 dm. in diameter; leaves bluish green, 

 rather thick, blunt-pointed, 1-2.5 cm. long; staniinate flowers purple; pistillate 

 flowers erect, dark-purple or yellowish green; cones cylindric, 3-7 cm. long; 

 scales persistent, obovate, striate. Tsuga Pattoniana Sen. T. Mertensiana 

 (Bong.) Sargent. H. Pattoniana Lemmon. Exposed ridges and slopes: Alaska 

 — w Mont. — -Ida. — -Calif. Subalp. 



10. PICEA Link. Spruces. 



Evergreen monoecious trees. Leaves needle-shaped, in ours quadrangular or 

 nearly terete, leaving persistent bases (sterigmata) when falling, scattered, 

 pointing in all directions. Staniinate aments from the axils of the leaves of the 

 preceding year, or rarely terminal; anther-sacs opening longitudinally. Pistil- 

 late aments terminal. Cones maturing the first season, drooping; scales closely 

 mibricate, leathery, thin, without dorsal thickening, persistent. Seeds samara- 

 like, with hj'aline wings, remaining attached to the seeds. 



Cone-scales rounded at the apex. 



Branchlets pubescent; cones 1.5-3 cm. long, persistent for several years; scales rigid, 



erose or dentate. 1. P. Mariana. 



Branchlets glabrous; cones 3-5 cm. long, deciduous in the first winter; scales rather 

 thin. 

 Cone-scales entire or minutely denticulate on the margins; cones cylindric- 



oblong, 3.5-5 cm. long. 2. P. canadensis. 



Cone-scales erose on the margins; cones ellipsoid, 3-3.5 cm. long. 3. P. alberliana. 

 Cone-scales more or less rhomboid in outline. 



Branchlets pubescent ; cones 3-5 cm. long. 4. P. Engelmanni. 



Branchlets glabrous; cones 5-9 cm. long. 5. P. pungens. 



1. P. Mariana (Mill.) B.S.P. A tree usually 6-10 m. high, occasionally 25 

 m. high, with a trunk 1-3 dm. in diameter; bark grayish bro^vn, scaly; twigs 

 russet-brown, short-pilose; leaves pale blue-green and glaucous, 1-2 cm. long, 

 caUous-tipped at the apex; staniinate flowers dark red; pistillate ones purple; 

 cones short, ovoid, 1-3 cm. long, ashy brown, persistent; scales rounded, erose- 

 dentate. P. nigra Link. Black Spruce. Swamps: Lab. — Ne-n-f. — N.C. — ■ 

 Wise. — -Sask.— Alta. — Mack. Boreal — -Subartic. 



2. P. canadensis (Mill.) B.S.P. A tree 10-20 m., rarely 30 m. high, with 

 a trunk 3-9 dm. in diameter; bark ashy brovra, scaly; branches and sterigmata 

 glabrous; leaves incurved, acute or acuminate, blue-green; staniinate flowers 

 pale red, becoming yellow from shedding the pollen; pistillate flowers pale red 

 or yellowish green; cones cylindric or oblong, 3-6 cm. long; scales orbicular, 

 slightly emarginate. P. alba Link. White Spruce. River banks and hill- 

 sides: Lab.— New^.— Me.— n N.Y.— Wise— S.D. (Black Hills)— Mta.— .Alaska. 

 Boreal — Subarctic. 



3. P. albertiana S. Browni. A slender tree 10-20 m. high; twigs and sterig- 

 mata smooth and shining, yellowish bro\^Ti, becoming darker in age; leaves 

 pale blue-green, 1.5-2.5 cm. long, incm-ved, acute or acuminate; pistillate flowers 

 bright crimson; cones ovate, 2.5-3.5 cm. long; scales stiff", rounded, cinnamon- 

 brown. Alberta Spruce. Mountains: Alta. — -n Wyo. — B.C. Mont. 



4. P. Engelmanni (Parry) Engelm. A tree 25-30 m., rarely 45 m. high, 

 with a trunk 4.5-10 dm. thick; bark Hght cinnamon-red, loosely scaly; leaves 

 soft, with acute tips, 2.5-3 cm. long, bluish green; staminate flowers dark purple; 

 pistillate ones scarlet, turning chestnut-brown; cones oblong-ellipsoid, subsessile, 

 3-6 cm. long; scales thin, erose-dentate. Engelmann's Spruce. Cold moiin- 

 tains and ravines, especially on the north sides: Alta. — N.M. — 'Ariz. — B.C. — 

 Yukon. Subalp. — Mont. 



