Part 6 (2/2)

c. Bark of trunk red-brown; cones maturing in second season, about 2 inches long; cone-scales thickened at the apex, but unarmed. _P. resinosa_, p. 15.

cc. Bark of trunk gray to nearly black; cones maturing in first season, 2-3 inches long; cone-scales thickened at the apex and topped with a short spine. _P. laricio austriaca_, p.

11.

+WINTER KEY TO THE SPECIES OF PINUS+

a. Leaves 5 in a cl.u.s.ter; cones 4-10 inches long. _P. strobus_, p. 7.

aa. Leaves 2 in a cl.u.s.ter; cones less than 4 inches long.

b. Leaves 1-3 inches long.

c. Leaves about 1 inch long, divergent; cones sessile, pointing forward towards the tip of the branch, persistent 10-15 years, opening very unevenly. _P. banksiana_, p. 9.

cc. Leaves 1-1/2-3 inches long, slightly divergent; cones stout-stalked, pointing away from the tip of the branch, maturing in second season, opening evenly. _P. sylvestris_, p.

13.

bb. Leaves 3-6 inches long.

c. Bark of trunk red-brown; cones maturing in second season, about 2 inches long; cone-scales thickened at the apex, but unarmed. _P. resinosa_, p. 15.

cc. Bark of trunk gray to nearly black; cones maturing in first season, 2-3 inches long; cone-scales thickened at the apex and topped with a short spine. _P. laricio austriaca_, p.

11.

[Ill.u.s.tration: +White Pine+

1. Cl.u.s.ter of leaves, 1.

2. Cross-sections of leaves, enlarged.

3. Partly opened cone, 3/4.

4. Cone-scale with seeds, 1.]

+PINACEAE+

+White Pine+

_Pinus strobus L._

HABIT.--A large tree 60-80 feet high, with a trunk diameter of 2-4 feet; forming a wide, pyramidal crown. Formerly trees 100-150 feet in height and 5-7 feet in trunk diameter were not exceptional.

LEAVES.--In cl.u.s.ters of five; 3-5 inches long; slender, straight, needle-shaped, 3-sided, mucronate; pale blue-green. Persistent about 2 years.

FLOWERS.--June; monoecious; the staminate oval, light brown, about 1/3 inch long, surrounded by 6-8 involucral bracts; the pistillate cylindrical, about 1/4 inch long, pinkish purple, long-stalked.

FRUIT.--Autumn of second season, falling during the winter and succeeding spring; pendent, short-stalked, narrow-cylindrical, often curved, greenish cones, 4-10 inches long; scales rather loose, slightly thickened at the apex; seeds red-brown, 1/4 inch long, with wings 1 inch long.

WINTER-BUDS.--Oblong-ovoid, sharp-pointed, yellow-brown, 1/4-1/2 inch long.

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