PINE FAMILY 13 



2. C. monophylla (Torr. & Frem.) Rydb. A tree usually 4-6 m., rarely 

 up to 15 m. high; bark irregularly furrowed, brown, tinged with red or orange; 

 branches smooth, light gray or yellowish; leaves single or in pairs, yellowish 

 green, incurved, 3-5 cm. long, when single terete, when in pairs flat and glaucous 

 on the inside; staminate flowers reddish; cones depressed-ovoid, 3-6 cm. long. 

 P. monophylla Torr. & Frem. ONE-LEAVED PINON. Dry hillsides and slopes: 

 Utah Ariz. L. Calif. Nev. Son. 'Submont. 



3. APINUS Necker. CEMBRA PINES. 



Monoecious trees or shrubs, with two kinds of leaves as in Pinus; secondary 

 leaves with single fibro-vascular bundles, in fascicles of 5. Staminate aments 

 as in Pinus. Pistillate cones subsessile below the terminal bud; scales in sev- 

 eral series. Cones maturing the second season, spreading; scales more or less 

 thickened, but without dorsal thickening or spine. Seeds large, edible, with a 

 very short wing or mere margin remaining attached to the scale when the seeds 

 faU. 



Cones 8-15 cm. long; scales neither much thickened nor impressed around the scar, 

 spreading at maturity. 1. A. flexilis. 



Cones 5-8 cm. long; scales much thickened and impressed around the terminal scar, 

 remaining closed. 2. A. albicaulis. 



1. A. flexilis (James) Rydb. A tree 10-15 m. high; bark of the old trunks 

 blackish or dark brown, deeply furrowed between rectangular blocks; that of 

 the branches light gray, shining, smooth; leaves dark green, crowded at the ends 

 of the branches, 3.5-7 cm. long; staminate flowers reddish; pistillate flow-ers red- 

 purple; cones 8-25 cm. long, ovoid, short-stalked; scales somewhat thickened, 

 opening at maturity, exposed portion greenish or yellowish brown, unexposed 

 portion pale red. Pinus flexilis James. LIMBER PINE. High mountains: 

 Alta. w Tex. se Calif. Submont. -Subalp. 



2. A. albicaulis (Engelm.) Rydb. A tree 1-10 m. high, rarely 15 m. high, 

 sometimes in exposed situations a mere sprawling shrub; bark of the trunks 

 thin, slightly if at all fissured, ashy; that of the branches yellowish, downy; 

 leaves crowded near the ends of the branches, dark green, 4-6 cm. long; flowers 

 scarlet; cones ovoid, horizontal, sessile, dark purple; scales much thickened, re- 

 maining closed. P. albicaulis Engelm. WHITE BARK or NUT PINE. High 

 exposed mountains: Alta. n Wyo. 'Calif. 'B.C. Mont. -Subalp. 



4. STROBUS Opiz. WHITE PINES. 



Monoecious evergreen trees, with two kinds of leaves as in Pinus; secondary 

 leaves mostly with a single fibro-vascular bundle, in fascicles of 5, surrounded at 

 the base by deciduous sheathing bud-scales. Staminate aments as in Pinus. 

 Pistillate cones stalked, borne behind the terminal bud; scales in many series. 

 Cones maturing the second season, drooping; scales becoming leathery, without 

 dorsal thickening or spine. Seeds with a well-developed wing remaining attached 

 to the seed. 



1. S. monticola (Dougl.) Rydb. A tree often 30 m., rarely 45 m. high, with 

 a trunk 7-12 dm. in diameter; bark of the trunk 2-3 cm. thick, grayish purple 

 to cinnamon-colored; leaves bluish green, whitened by 2-6 rows of stomata, 5-10 

 cm. long; staminate flowers yellow; pistillate cones purple, 1.5-2.5 dm. long; tips 

 of scales reddish- or yellowish-brown, lower and inside portions bright red. P. 

 monticola Dougl. WESTERN WHITE PINE. Mountains: B.C. -nw Mont. 

 Ida. s Calif. Submont. Mont. 



5. LARIX (Tourn.) Adans. LARCH, TAMARACK. 



Slender deciduous monoecious trees. Leaves needle-shaped, soft, very many 

 in each fascicle, developed in early spring from lateral scaly buds. Staminate 

 aments terminating short lateral branches of the preceding year, from naked 

 buds. Anthers 2-celled, opening transversely; pollen-grains 1-celled, globular. 

 Pistillate aments crimson, usually subtended by leaves; cone-scales persistent. 

 Seeds samara-like; wings attached to the seeds. 



