PINE FAMILY 13 



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

 up to 15 m. high; bark irregularly fiuTowed, 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. vionophylla Torr. & Frem. One-leaved Pin on. Drj^ hillsides and slopes: 

 Utah — Ariz. — L. Calif. — -Nev. Son. — Submont. 



3. APINUS Necker. Cembra Pines. 



Monoecious trees or slirubs, 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 tliickened nor impressed around the scar, 

 spreading at maturity. 1. A. fleiilis. 



Cones 5-8 cm. long; scales much tliickened 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 hght gray, shuiing, smooth; leaves dark green, crowded at the ends 

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

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

 opening at matiu-ity, exposed portion gi-eenish or yellowish brown, miexposed 

 portion pale red. Pinus flexilis James. Limber Pine. High mountains: 

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



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

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

 thin, sUghtly if at all fissured, ashy; that of the branches yellowish, dovMiy; 

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

 scarlet; cones ovoid, horizonta.1, 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, di'ooping; 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 pm-ple, 1.5-2.5 dm. long; tips 

 of scales reddish- or yellowish-bro%vn, lower and inside portions bright red. P. 

 monticola Dougl. Western White Pine. Moimtains: 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-ceUed, globular. 

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

 Seeds samara-hke; wings attached to the seeds. 



