Part 13

Pinus banksiana Lamb. [Pinus divaricata (Ait.) Du Mont de Cours.]

HABIT.--Usually a small tree 20-30 feet high, with a trunk diameter of 8-12 inches; forming a crown varying from open and symmetrical to scrubby, stunted, and variously distorted.

LEAVES.--In clusters of two; about 1 inch long; narrow-linear, with sharp-pointed apex; stout, curved or twisted, divergent from a short sheath; dark gray-green. Persistent 2-3 years.

FLOWERS.--May-June; monoecious; the staminate in oblong clusters 1/2 inch long, composed of many sessile, yellow anthers imbricated upon a central axis; the pistillate in subglobose clusters, composed of many carpel-like, purple scales (subtended by small bracts) spirally arranged upon a central axis.

FRUIT.--Autumn of second or third season, but remaining closed for several years and persistent on the tree for 10-15 years; erect, usually incurved, oblong-conical, sessile cones, 1-1/2-2 inches long; scales thickened at the apex; seeds triangular, nearly black, 3/8 inch long, with wings 1/3 inch long.

WINTER-BUDS.--Terminal bud 1/4 inch long, ovoid, rounded, pale brown; lateral buds smaller.

BARK.--Twigs yellow-green, becoming purple, finally dark red-brown and rough with the persistent bases of fallen leaves; thin, dark red-brown on the trunk, with shallow, rounded ridges, rough-scaly on the surface.

WOOD.--Light, soft, weak, close-grained, light brown, with thick, whitish sapwood.

DISTRIBUTION.--Common from Clare County northward; occurs sparingly along the lake shore as far south as Grand Haven on the west and Port Austin on the east.

HABITAT--Sandy, sterile soil.

NOTES.--Cones open unevenly. Slow of growth. Difficult to transplant.

1. Cluster of leaves, × 1. 2. Cross-section of leaf, enlarged. 3. Unopened cone, × 1. 4. Partly opened cone, × 1/2. 5. Cone-scale with seeds, × 1.]

+PINACEAE+

+Austrian Pine. Black Pine+

Pinus laricio austriaca Endl. [Pinus austriaca Höss.]

HABIT.--A large tree 60-80 feet high, with a trunk diameter of 2-4 feet; forming a massive, spreading crown of stiff, strong branches.

LEAVES.--In clusters of two; 3-6 inches long; slender, rigid, sharp-pointed, curved towards the twig; deep green on both faces. Persistent 3-6 years.

FLOWERS.--May-June; monoecious; the staminate cylindrical, subsessile, bright yellow, about 3/4 inch long; the pistillate cylindrical, small, bright red, subsessile.

FRUIT.--Autumn of first season, opening two years after full size is attained and remaining on the tree several years; erect, sessile, long-ovoid cones 2-3 inches long; scales smooth, lustrous, thickened at the apex and topped with a short spine in the center; seeds red-brown, 1/4 inch long, with wings 3/4 inch long.

WINTER-BUDS.--Oblong-conical, sharp-pointed, red-brown, resinous, about 1/2 inch long.

BARK.--Twigs brownish to olive-brown and smooth, becoming darker with age; thick, gray to nearly black on old trunks and coarsely and deeply fissured.

WOOD.--Light, strong, very resinous, red-brown, with thick, yellowish to reddish white sapwood.

NOTES.--Perfectly hardy. Adapts itself to a variety of soils. Well adapted for screens and wind-breaks. Easily transplanted when small. Grows rapidly.

1. Cluster of leaves, × 1. 2. Cross-section of leaf, enlarged. 3. Unopened cone, × 1. 4. Partly opened cone, × 1. 5. Cone-scale with seeds, × 1.]

+PINACEAE+

+Scotch Pine. Scotch Fir+

Pinus sylvestris L.

HABIT.--A large tree 60-80 feet high, with a trunk diameter of 1-2 feet; the side branches persist, forming a massive, wide-spreading crown.