32 PINACEAE (PINE FAMILY) 



PICEA (Spruce) 



Trees. Leaves mostly not complanate, 4-angled, scattered. Staminate 

 cones oblong or oval or cylindric, long-stalked. Mature pistillate cones 

 ovoid or oblong-cylindric. Scales thin, obtuse. — Good trees for lumber 

 and paper. (Latin name.) 



A. Cone scales entire, broadly ovate, rounded at apex; leaves obtuse, somewhat 



flat; branchlets pubescent. U. P. brewerlana (weeping spruce) 



AA. Cone scales not entire, mostly contracted at both ends; leaves acute or acuminate, 



4-sided or somewhat rounded. 



B. Branchlets pubescent; leaves 4-sided, with stomates on 4 sides; cones about 



5 cm. long; cone scales gradually narrowed to an acute or truncate tip; crushed 



leaves with decided skunklike smell. C. E. P. enge^anni (engelmann spruce) 



BB. Branchlets glabrous; leaves hardly 4-sided, usually with stomates on the upper 



side only; cones 5-10 cm. long; cone scales rounded at tip; crushed leaves with 



little or no skunklike smell. W. P. sitchensls (sitka spruce) 



LARK (Larch) 



Trees with many knoblike branches on their twigs. Leaves 3-4-angled, 

 some in bunches of 10 or more on the knoblike branches, others scattered 

 on the elongated twigs. Staminate cones globose to oblong. Pistillate 

 cones conical to subglobose; scales slightly thickened, suborbicular or 

 oblong-ovate. — Lumber trees. (Celtic name.) 



A. Leaves 3-angled: branchlets and bud scales pubescent but soon become glabrous; 



cones 2. 5-3. 7 cm. long. C. E. L. occldentalls (western larch) 



AA. Leaves 4-angled; branchlets and bud scales tomentose; cones 3. 7-5 cm. long. 



C. E. L. lyallU (woollv larch) 



PINUS (Pine) 



Trees or shrubs. Staminate cones involucrate. Scales of pistillate cones 

 thickened at tip, woody, tipped with a scar or protuberance. — Mostly 

 lumber trees. (Latin name.) 



A. 2 leaves in a bunch. 



B. Leaves 2.5-7.5 cm. long, all in 2's; cones 1.5-5 cm. long, remaining on the trees 

 for s-30 years. W. C. E. P. contorta (lodge-pole pine) 



BB. Leaves 10-27 cm. long, often some in 3's; cones 7. 5-37. 5 cm. long, dropping 

 within 2 years. W. C. E. P. ponderosa (yellow pine) 



AA. 3 leaves in a bunch. 



C. Leaves in 2's or 3's; cones subterminal, falling within 2 years. (See BB.) 

 CC. Leaves all in 3's; cones lateral, remaining 2 to many years. C. 



P. attenuata (knob-cone pine) 

 AAA. 5 leaves in a bunch. 



D. Cones 3.7-12.5 cm. long (in P. flexilis 7.5-23 cm.), their stalks 2-7 mm. long; 

 cone scales with prickles, thick; seeds longer than their wings (except in P. bal~ 

 fouriana); leaves 2.5-7.5 cm. long; bark whitish where smooth. 



E. Leaves 2.5-3.7 cm. long, persistent for 10-12 years; old bark divided into 

 isodiametric plates; cones 8.7-12,5 cm. long, opening at maturity; prickles of 

 cone scales on back and not at very tip, pointing away from cone axis. U. 



P. balfouriaoa (foxtail pine) 



