56 



PINACEAE. 



Vol. I. 



i. PINUS [Tourn.] L. Sp. PI. iooo. 1753. 



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

 ous, 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, com- 

 posed 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. The popular names of the species are much confused.] 



About 100 species, natives of the northern hemisphere. In addition to the following, 25 others 

 occur in southern and western North America. Type species : Pinus sylvestris L., of Europe. 

 The group of which Pinus Strobus L. is the type is regarded'by some authors as a distinct genus. 



Leaves 5 in a sheath ; cone-scales little thickened at the tip. 

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

 Cones terminal or subterminal. 



Leaves 2 in a sheath; cones iK' -2 /^' long, their scales pointless. 

 Leaves 3 in a sheath; cones 4'-io' long, their scales prickle-tipped. 

 Cones light, 6'-io' long; leaves io'-i6' long. 

 Cones very heavy and woody, 3'-4}4' long; leaves 3'-6' long. 

 Cones lateral. 



Cone-scales, with neither spine nor prickle; leaves in 2's. 

 Cone-scales tipped with a spine or prickle. 

 Leaves some or all of them in 2's. 



Cones i$4'-2$4' long, their scales tipped with prickles. 

 Leaves stout, i}4'-2^' long. 

 Leaves slender, 3'— 5' long. 

 Cones 3j4'-s' long, their scales tipped with very stout short spines. 



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



Cones oblong-conic; leaves 6'-io' long; old sheaths 6"-io" long. 

 Cones ovoid. 



Leaves 3'-$' long ; cone-scales with stiff prickles. 



Leaves 6'-io' long; cone-scales with small slender deciduous or 



i. Pinus Strobus L. White Pine. Weymouth Pine. Fig. 131. 



Pinus Strobus L. Sp. PI. iooi. 1753. 



A large forest tree, reaching a maximum height 

 of over 225° and a trunk diameter of io4°, the 

 bark nearly smooth except when old, the branches 

 horizontal, verticillate. Leaves 5 in a sheath, very 

 slender, pale green and glaucous, 3-5' long, with 

 a single fibro-vascular bundle, the dorsal side 

 devoid of stomata ; sheath loose, deciduous ; 

 ovule-bearing aments terminal, peduncled; cones 

 subterminal, drooping, cylindric, often slightly 

 curved, 4'-6' long, about 1' thick when the scales 

 are closed, resinous; scales but slightly thickened 

 at the apex, obtuse and rounded or nearly trun- 

 cate, without a terminal spine or prickle. 



In woods, often forming dense forests, Newfound- 

 land to Manitoba, south to Delaware, along the 

 Alleghanies to Georgia and to Illinois and Iowa. 

 Ascends to 4300 ft. in North Carolina and to 2500 

 ft. in the Adirondacks. Wood light brown or nearly 

 white, soft, compact, one of the most valuable of 

 timbers ; weight per cubic foot, 24 lbs. June. Called 

 also Soft, Deal, Northern or Spruce-pine. 



