Leaves 4-sided, with stomata on the 4 sides. Cone-scales rounded at apex. Cone-scales stiff and rigid at maturity; branchlets pubescent. Cones ovoid on strongly incurved stalks, persistent for many years, their scales erose or dentate; leaves blue-green. 1. P. mariana (A, B, F). Cones ovoid-oblong, early deciduous, their scales entire or denticulate; leaves dark yellow-green. 2. P. rubra (A). Cone-scales soft and flexible at maturity; branchlets glabrous; cones oblong-cylindric, slender, their scales entire; leaves blue-green. 3. P. glauca (A, B, F). Cone-scales truncate or acute at apex, oblong or rhombic; leaves blue-green. Cones oblong-cylindric or ellipsoidal; branchlets pubescent; leaves soft and flexible. 4. P. Engelmannii (F, B, G). Cones oblong-cylindric; branchlets glabrous; leaves rigid, spinescent. 5. P. pungens (F). Leaves flattened, usually with stomata only on the upper surface; cone-scales rounded. Cone-scales ovate, entire; branchlets pubescent; cones ellipsoidal, leaves obtuse. 6. P. Breweriana (G). Cone-scales elliptic, denticulate above the middle; branchlets glabrous; cones oblong-cylindric, leaves acute or acuminate, with stomata occasionally on the lower surface. 7. P. sitchensis (B, G). 1. Picea mariana B. S. P. Black Spruce. [Illustration: Fig. 39] Leaves slightly incurved above the middle, abruptly contracted at apex into short callous tips, pale blue-green and glaucous at maturity, ¼′—¾′ long, hoary on the upper surface from the broad bands of stomata, and lustrous and slightly stomatiferous on the lower surface. Flowers: male subglobose, with dark red anthers; female oblong-cylindric, with obovate purple scales rounded above, and oblong purple glaucous bracts rounded and denticulate at apex. Fruit ovoid, pointed, gradually narrowed at the base into short strongly incurved stalks, ½′—1½′ long, with rigid puberulous scales rounded or rarely somewhat pointed at apex and more or less erose on the notched pale margins, turning as they ripen dull gray-brown and becoming as the scales gradually open and slowly discharge their seeds almost globose; sometimes remaining on the branches for twenty or thirty years, the oldest close to the base of the branches near the trunk; seeds oblong, narrowed to the acute base, about ⅛′ long, very dark brown, with delicate pale brown wings broadest above the middle, very oblique at the apex, about ½′ long, ⅛′ wide.