Part 11

i. Bud at end of twig very obliquely unsymmetrical, mucilaginous when chewed. TILIA, p. 201.

ii. Bud at end of twig symmetrical, not mucilaginous when chewed.

j. Bud-scales 2-3 visible; pith star-shaped in cross-section; sap not milky; fruit a prickly bur, present; large tree. CASTANEA, p. 95.

jj. Bud-scales 4-8 visible; pith not star-shaped in cross-section; sap milky; fruit berry-like, not present; small tree. MORUS, p. 135.

MANUAL OF TREES

DESCRIPTION OF SPECIES

WITH

SUMMER AND WINTER KEYS

TO THE SPECIES

1. Winter twig, × 1/2. 2. Leaf, × 1/2. 3. Staminate flowering branchlet, × 1/2. 4. Staminate flower, enlarged. 5. Pistillate flower, enlarged. 6. Fruit, × 1.]

+GINKGOACEAE+

+Ginkgo. Maidenhair Tree+

Ginkgo biloba L. [Salisburia adiantifolia Smith]

HABIT.--A slender tree in youth, with slender, upright branches, becoming broader with age and forming a symmetrical, pyramidal crown; probably 60-80 feet high, with a trunk diameter of 2-4 feet.

LEAVES.--Clustered at the ends of short, spur-like shoots, or scattered alternately on the long terminal branches; simple; 2-5 inches broad; more or less fan-shaped; usually bilobed and irregularly crenate at the upper extremity; thin and leathery; glabrous, pale yellow-green on both sides; petioles long, slender; turning a clear, golden yellow before falling in autumn.

FLOWERS.--May, with the leaves; dioecious; the staminate in short-stalked, pendulous catkins, 1 to 1-1/2 inches long, yellow; the pistillate more or less erect on the shoot, long-stalked, consisting of 2 naked ovules, one of which usually aborts.

FRUIT.--Autumn; a more or less globose drupe, orange-yellow to green, about 1 inch in diameter, consisting of an acrid, foul-smelling pulp inclosing a smooth, whitish, somewhat flattened, almond-flavored nut.

WINTER-BUDS.--Terminal bud about 1/8 inch long, conical, smooth, light chestnut-brown; lateral buds divergent, usually only on rapid-growing shoots.

BARK.--Twigs gray-brown and smooth; thick, ash-gray and somewhat roughened on the trunk, becoming more or less fissured in old age.

WOOD.--Light, soft, weak, close-grained, yellow-white to light red-brown, with thin, lighter colored sapwood.

NOTES.--Origin in dispute, but probably a native of northern China. Extensively cultivated in China and Japan, where its fruit is esteemed. Easily propagated from seed. Thrives in deep, well-drained, rich soil. Practically free from insect and fungous attacks, and little harmed by the smoke of cities. Probably hardy throughout the southern half of the Lower Peninsula.

+SUMMER KEY TO THE SPECIES OF PINUS+

a. Leaves 5 in a cluster; cones 4-10 inches long. P. strobus, p. 7.

aa. Leaves 2 in a cluster; 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.