S 
50 PINACEAE. 
PINUS L. Sp. Pl. 1000. 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. 
Oyule-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. ] 
Leaves 5 in a sheath; cone-scales little thickened at the tip. 1. 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 14! —2%4' long, their scales pointless. 2. P. resinosa, 
Leaves 3 in a sheath; cones 4'-10' long, their scales prickle-tipped. 
Cones light, 6’-10’ long; leaves 10 “16! long. 
Cones very heavy and woody, 4'-6' long; leaves 5'-10' long. 
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 14/-2's' long, their scales tipped with prickles. 
Leaves stout, 136’ 254" long. P. Virginiana. 
Leaves slender, 3 -5' long. . P. echinata, 
Cones 3''-5' long, tbeis ate tipped with very stout short spines. 
8. P. pungens. 
. P. palustris. 
P. ponderosa. 
Fu 
10 
Leaves in 3’s (very rarely some in 2’s or aS) 
Leaves 6'—10! long; old sheaths 6’’—r10'’ long; cones oblong-conic. 9. P. Taeda. 
Leaves 3'-5' long; old sheaths 3'’-6'’ long; cones ovoid. 10. P. rigida. 
1. Pinus Strobus L. White Pine. Weymouth Pine. (Fig. 110.) 
Pinus Strobus ¥,. Sp. Pl. toot. 1753. 
A large forest tree, reaching a maximum 
height of 175° and a trunk diameter of 10's°, 
the bark nearly smooth except when old, the 
branches horizontal, verticillate. Leaves 5 
in a sheath, very slender, pale green and glau- 
cous, 3/-5’ long, with a single fibro-vascular 
bundle, the dorsal side devoid of stomata ; sheath 
loose, deciduous; ovule-bearing aments ter- 
minal, peduncled; cones subterminal, droop- 
ing, cylindric, often slightly curved, 4/-6’ long, 
about 1’ thick when the scales are closed, re- 
sinous; scales but slightly thickened at the 
apex, obtuse and rounded or nearly truncate, 
without a terminal spine or prickle. 
In woods, often forming dense forests, Newfound- 
land to Manitoba, south along the Alleghenies to 
Georgia and to Illinois and Iowa. Ascends to 4300 
ft. in North Carolina and to 2500 ft. in the Adiron- 
dacks. Wood light brown or nearly white, soft, 
compact, one of the most valuable of timbers; 
weight per cubic foot, 24 lbs. June. 
