PINACEAE. 31 



Scales of the cone numerous (except in Larix) ; leaf-buds scaly. 



Cone-scales woody ; leaves needle-shaped, 2-5 in a sheath. i. Pinus. 

 Cone-scales thin ; leaves linear-filiform, scattered or fascicled, not in sheaths. 



Leaves fascicled on very short branchlets, deciduous. 2. Larix. 

 Leaves scattered, persistent. 



Cones pendulous ; leaves jointed to short persistent sterigmata. 



Leaves tetragonal, sessile. 3. Picea. 



Leaves flat, short- petioled. 4. Tsuga. 



Cones erect ; sterigmata inconspicuous ox noie. 5. Abies. 

 Scales of the cone few (3-12); leaf-buds naked. 



Cone-scales spiral, thick ; leaves deciduous. 6. Taxodium. 

 Cone-scales opposite ; leaves persistent. 



Cone oblong, its scales not peltate. 7. Thuja. 



Cone globose, its scales peltate. 8. Chamaecyparis. 



Fruit fleshy, berry-like, a modified cone. 9. Jimiperus. 



i. PINUS L. (See Appendix.) 



Evergreen trees with two kinds of leaves, the primary ones linear or scale-like, 

 deciduous, the secondary ones forming the ordinary foliage, narrowly linear, 

 arising from the axils of the former in fascicles of 2-5 (rarely solitary in some 

 western species), subtended by the bud-scales, some of which are united to form a 

 sheath. Staminate aments borne at the bases of shoots of the season, the clusters of 

 stamens spirally arranged, each in the axil of a minute scale ; filaments very short ; 

 anthers 2-celled, the sacs longitudinally dehiscent. Ovule-bearing aments solitary 

 or clustered, borne on the twigs of the preceding season, composed of numerous 

 imbricated minute bracts, each with an ovule-bearing scale in its axil, ripening 

 into a large cone, which matures the following autumn, its scales elongating and 

 becoming "woody. Seeds 2 on the base of each scale, winged above, the testa 

 crustaceous. [Name Celtic.] About 75 species, of the northern hemisphere. 



Leaves 5 in a sheath ; cone-scales little thickened at the tip. i. P, Strobus. 



leaves 2-3 in a sheath ; cone-scales much thickened at the tip. 

 Cones terminal or subterminal. 



Leaves 2 in a sheath ; cones 3-6 cm. long, their scales pointless. 



2. P. resinosa. 

 Leaves 3 in a sheath ; cones 1-2.5 dm. long, their scales prickle-tipped. 



Cones light, 1.5-2.5 dm. long; leaves 2.5-4 dm. long. 3. P. palustris. 

 Cones very heavy and woody, 1-1.5 dm. l n Sj leaves 1.2-2.5 dm. l n g- 



4. P. ponderosa. 

 Cones lateral. 



Cone-scales with neither spine nor prickle ; leaves in 2 ? s 5. P- divaricata. 

 Cone-scales tipped with a spine or prickle. 

 Leaves some or all of them in 2's. 



Cones 3-7 cm. long, their scales tipped with prickles. 



Leaves stout, 3-6 cm. long. 6. P. Virgtniana. 



Leaves slender, 7-13 cm. long. 7. P, echinata. 



Cones 8-12 cm. long, their scales tipped with very stout short spines. 



8. P. pungens. 

 Leaves in 3*5 (very rarely some in 2's or 4's). 



Leaves 1.5-2.5 dm. long ; old sheaths 1-2.5 cm - l n g > cones oblong-conic. 



9. P. Taeda. 

 Leaves 7-13 cm. long; old sheaths 0.6-1.2 cm. long; cones ovoid. 



10. P. rigida. 



1. Pinus Strobus L. WHITE PINE. WEYMOUTH PINE. (I. F. f. no.) A large 

 forest tree, the bark nearly smooth except when old, the branches horizontal, 

 verticillate. Leaves 5 in a sheath, very slender, pale green and glaucous, 7-12 cm. 

 long, with a single fibro- vascular bundle, the dorsal side devoid of stomata; sheaths 

 loose, deciduous; ovule-bearing aments terminal, peduncled; cones subterminal, 

 drooping, cylindric, often slightly curved, 10-15 cm - lon g> ab o u t 2 -5 cm - tnick 

 when the scales are closed, resinous; scales slightly thickened at the apex, obtuse 

 and rounded or nearly truncate, without a terminal spine or prickle. In woods, 

 often forming dense forests, Newf. to Man., south along the Allegh. to Ga. and to 

 111. and la. June. 



2. Pinus resinosa Ait. CANADIAN PINE. RED PINE. (I. F. f. in.) A tall 

 forest tree, the bark reddish, rather smooth, flaky when old. Leaves 2 in each 

 sheath, slender, dark green, 10-15 cm - l n g> w * tn 2 fibro- vascular bundles; sheaths 



