Scales of the female flowers numerous; spirally arranged in the axils of persistent bracts; ovules 2, inverted; seeds borne directly on the scales, attached at the base in shallow depressions on the inner side of the scales, falling from them at maturity and usually carrying away a scarious terminal wing; leaves fascicled or scattered (deciduous in Larix). Abietineæ. Fruit maturing in two or rarely in three seasons; leaves fascicled, needle-shaped in axillary 1—5-leaved clusters, inclosed at the base in a membranaceous sheath; cone-scales thick and woody, much longer than their bracts.1. [Pinus.] Fruit maturing in one season. Leaves in many-leaved clusters on short spur-like branchlets, deciduous; cone-scales thin, usually shorter than their bracts.2. [Larix.] Leaves scattered, linear. Cones pendulous, the scales persistent on the axis. Branchlets roughened by the persistent leaf-bases; leaves deciduous in drying; bracts shorter than the cone-scales. Leaves sessile, 4-sided, or flattened and stomatiferous above.3. [Picea.] Leaves stalked, flattened and stomatiferous below, or angular.4. [Tsuga.] Branchlets not roughened by leaf-bases; leaves stalked, flattened; not deciduous in drying; bracts of the cone 2-lobed, aristate, longer than the scales.5. [Pseudotsuga.] Cones erect, their scales deciduous from the axis, longer or shorter than the bracts; leaves sessile, flat or 4-sided.6. [Abies.] Scales of the female flowers without bracts; ovules and seeds borne on the face of minute scales adnate to the base of the flower-scales, enlarging and forming the scales of the cone. Seeds with a narrow marginal wing (wingless in Juniperas). Scales of the female flowers numerous, spirally arranged, forming a woody cone; ovules erect, 2 or many under each scale; leaves linear, alternate, often of 2 forms (deciduous in Taxodium). Taxodiæ. Ovules and seeds numerous under each scale.7. [Sequoia.] Ovules and seeds 2 under each scale; leaves mostly spreading in 2 ranks.8. [Taxodium.] Scales of the female flower few, decussate, forming a small cone, or rarely a berry; ovules 2 or many under each scale; leaves decussate or in 3 ranks, often of 2 forms, usually scale-like, mostly adnate to the branch, the earliest free and subulate. Cupressineæ. Fruit a cone; leaves scale-like. Cones oblong, their scales oblong, imbricated or valvate; seeds 2 under each scale, maturing the first year. Scales of the cone 6, the middle ones only fertile; seeds unequally 2-winged.9. [Libocedrus.] Scales of the cone 8—12; seeds equally 2-winged.10. [Thuja.] Cones subglobose, the scales peltate, maturing in one or two years; seeds few or many under each scale. Fruit maturing in two seasons; seeds many under each scale; branchlets terete or 4-winged.11. [Cupressus.] Fruit maturing in one season; seeds 2 under each scale; branchlets flattened.12. [Chamæcyparis.] Fruit a berry formed by the coalition of the scales of the flower; ovules in pairs or solitary; flowers diœcious; leaves decussate or in 3’s, subulate or scale-like, often of 2 forms.13. [Juniperus.]
1. PINUS Duham. Pine.
Trees or rarely shrubs, with deeply furrowed and sometimes laminate or with thin and scaly bark, hard or often soft heartwood often conspicuously marked by dark bands of summer cells impregnated with resin, pale nearly white sapwood, and large branch-buds formed during summer and composed of minute buds in the axils of bud-scales, becoming the bracts of the spring shoot. Leaves needle-shaped, clustered, the clusters borne on deciduous spurs in the axils of scale-like primary leaves, inclosed in the bud by numerous scales lengthening and forming a more or less persistent sheath at the base of each cluster. Male flowers clustered at the base of leafy growing shoots of the year, each flower surrounded at the base by an involucre of 3—6 scale-like bracts, composed of numerous sessile anthers, imbricated in many ranks and surmounted by crest-like nearly orbicular connectives; the female subterminal or lateral, their scales in the axils of non-accrescent bracts. Fruit a woody cone maturing at the end of the second or rarely of the third season, composed of the hardened and woody scales of the flower more or less thickened on the exposed surface (the apophysis), with the ends of the growth of the previous year appearing as terminal or dorsal brown protuberances or scars (the umbo). Seeds usually obovoid, shorter or longer than their wings or rarely wingless; outer seed-coat crustaceous or thick, hard, and bony, the inner membranaceous; cotyledons 3—18, usually much shorter than the inferior radicle.
Pinus is widely distributed through the northern hemisphere from the Arctic Circle to the West Indies, the mountains of Central America, the Canary Islands, northern Africa, the Philippine Islands, and Sumatra. About sixty-six species are recognized. Of exotic species the so-called Scotch Pine, Pinus sylvestris L., of Europe and Asia, the Swiss Stone Pine, Pinus cembra L., and the Austrian Pine and other forms of Pinus nigra Arnold, from central and southern Europe, are often planted in the northeastern states, and Pinus Pinaster Ait., of the coast region of western France and the Mediterranean Basin is successfully cultivated in central and southern California. Pinus is the classical name of the Pine-tree.
The North American species can be conveniently grouped in two sections, Soft Pines and Pitch Pines.
SOFT PINES.
Wood soft, close-grained, light-colored, the sapwood thin and nearly white; sheaths of the leaf-clusters deciduous; leaves with one fibro-vascular bundle.
Leaves in 5-leaved clusters. Cones long-stalked, elongated, cylindric bright green at maturity, becoming light yellow brown, their scales thin, with terminal unarmed umbos; seeds shorter than their wings. White Pines. Leaves without conspicuous white lines on the back. Leaves slender, flexible; cones 4′—8′ long.1. [P. Strobus] (A). Leaves stout, more rigid; cones 5′—11′ long.2. [P. monticola] (B, G). Leaves with conspicuous white lines on the back; cones 12′—18′ long.3. [P. Lambertiana] (G). Cones short-stalked, green or purple at maturity, their scales thick. Cones cylindric or subglobose, their scales with terminal umbos; leaves 2′ long or less. Stone Pines. Cones 3′—10′ long, their scales opening at maturity; seeds with wings.4. [P. flexilis] (F, H). Cones ½′—3′ long, their scales remaining closed at maturity; seeds wingless.5. [P. albicaulis] (B, F, G). Cones ovoid-oblong, their scales with dorsal umbos armed with slender prickles; seeds shorter than their wings; leaves in crowded clusters, incurved, less than 2′ long. Foxtail Pines. Cones armed with minute incurved prickles.6. [P. Balfouriana] (G). Cones armed with long slender prickles.7. [P. aristata] (F, G). Leaves in 1—4-leaved clusters; cones globose, green at maturity, becoming light brown, their scales few, concave, much thickened, only the middle scales seed-bearing; seeds large and edible, their wings rudimentary; leaves 2′ or less, often incurved. Nut Pines.8. [P. cembroides] (C, F, G, H).
1. [Pinus Strobus] L. White Pine.
