An Illustrated Flora of the Northern United States, Canada and the British Possessions/Pinaceae

Scales of the cone numerous (except in Larix); leaf-buds scaly. Cone-scales woody; leaves needle-shaped, 2-5 in a sheath. Cone-scales thin; leaves linear-filiform, scattered or fascicled, not in sheaths. Leaves fascicled on very short branchlets, deciduous. Leaves scattered, persistent. Cones pendulous; leaves jointed to short persistent sterigmata. Leaves tetragonal, sessile. Leaves flat, short-petipled. Cones erect; sterigmata inconspicuous or none. Scales of the cone few (3-12); leaf-buds naked. Cone-scales spiral, thick; leaves deciduous. Cone-scales opposite; leaves persistent. Cone oblong, its scales not peltate. Cone globose, its scales peltate. Fruit fleshy, berry-like, a modified cone.

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 1½'-2½' long, their scales pointless. 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, 3'-4½' 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 1½'-2½' long, their scales tipped with prickles. Leaves stout, 1½'-2½' long. Leaves slender, 3'-5' long. Cones 3½'-5' 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'-10' long; old sheaths 6"-10" long. Cones ovoid. Leaves 3'-5' long; cone-scales with stiff prickles. Leaves 6'-10' long; cone-scales with small slender deciduous or obsolete prickles.