Michigan Trees Part 13

FLOWERS.--April-May, with the leaves; dioecious; borne in slender, p.u.b.escent catkins 1-3 inches long; calyx 0; corolla 0; scales blunt, somewhat p.u.b.escent; stamens usually 2; ovary abortive, with stigmas nearly sessile. Staminate trees rare.

FRUIT.--April-May; 1-celled, long-conical, short-stalked capsule, about 1/4 inch long, containing many minute seeds which are furnished with long, silky, white hairs.

WINTER-BUDS.--Terminal bud absent; lateral buds long-conical, pointed, glabrous, bright red-brown, about 1/4 inch long.

BARK.--Twigs p.u.b.escent, yellow-green, often reddish, becoming glabrous, l.u.s.trous, brown; thick, gray on the trunk, smooth in young trees, very rough, irregularly scaly-ridged in old trees.

WOOD.--Light, soft, tough, close-grained, red-brown, with thick, whitish sapwood.

NOTES.--A native of Europe and Asia, where it is a valuable timber tree.

Hardy throughout the state and of very rapid growth. Thrives in rich, damp soil. Easily grown from cuttings. The twigs are very brittle at the base and are easily broken by the wind, hence the name Brittle Willow.

[Ill.u.s.tration: +Weeping Willow. Napoleon's Willow+

1. Winter twig, 1.

2. Portion of twig, enlarged.

3. Leaf, 1.

4. Pistillate flowering branchlet, 1/2.

5. Pistillate flower, enlarged.

6. Fruiting branchlet, 1/2.]

+SALICACEAE+

+Weeping Willow. Napoleon's Willow+

_Salix babylonica L._

HABIT.--A tree 40-50 feet high, with a short, stout trunk 3-4 feet in diameter; the long, slender branchlets, often many feet in length, droop in graceful festoons, giving to the tree a weeping habit.

LEAVES.--Alternate, simple, 3-7 inches long, 1/4-1/2 inch broad; linear to linear-lanceolate, long-pointed; finely sharp-serrate; thin and firm; glabrous, dark green above, paler beneath; petioles 1/2 inch or less in length, glandular above, often hairy.

FLOWERS.--April-May, with the leaves; dioecious; borne in slender, nearly glabrous catkins 1-2 inches long; calyx 0; corolla 0; scales ovate-lanceolate, slightly hairy; ovary ovoid-conical, very short-stalked, with stigmas longer than the style. Staminate trees apparently do not occur in the United States.

FRUIT.--May-June; 1-celled, narrow-ovoid, sessile capsule, about 3/16 inch long, containing many minute seeds which are furnished with long, silky, white hairs.

WINTER-BUDS.--Terminal bud absent; lateral buds narrow-conical, sharp-pointed, somewhat flattened, brownish, 1/8-1/4 inch long.

BARK.--Twigs glabrous, olive-green; thick and gray on old trunks, rather smooth, or irregularly fissured into shallow, firm ridges.

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

NOTES.--A native of Europe and Asia. Often grown in cemeteries. Easily propagated by cuttings. Rapid of growth in rich, damp soil. Sometimes winter-killed because the wood is not ripened.

SUMMER KEY TO THE SPECIES OF POPULUS

a. Leaf-petioles essentially terete.

b. Petioles and lower sides of leaves p.u.b.escent; leaves heart-shaped. _P. candicans_, p. 55.

bb. Petioles and lower sides of leaves glabrous; leaves ovate-lanceolate. _P. balsamifera_, p. 53.

aa. Leaf-petioles strongly flattened.

b. Petioles and lower sides of leaves tomentose; twigs p.u.b.escent. _P. alba_, p. 47.

bb. Petioles and lower sides of leaves glabrous; twigs glabrous.

c. Leaves distinctly deltoid in shape.

d. Leaves broader than they are long, abruptly ac.u.minate at the apex; marginal teeth not conspicuously incurved; branches erect and more or less appressed to the main stem, forming a narrow, spire-like crown. _P. nigra italica_, p. 59.

dd. Leaves longer than they are broad, more or less taper-pointed at the apex; marginal teeth rather conspicuously incurved; branches spreading, forming a broad crown. _P.

deltoides_, p. 57.

cc. Leaves ovate to nearly orbicular in shape.

d. Margin of leaves coa.r.s.ely sinuate-toothed; leaves 3-5 inches long. _P. grandidentata_, p. 51.

dd. Margin of leaves finely serrate; leaves less than 3 inches long. _P. tremuloides_, p. 49.

+WINTER KEY TO THE SPECIES OF POPULUS+

a. Branches erect, more or less appressed to the main stem, forming a narrow, spire-like crown. _P. nigra italica_, p. 59.

aa. Branches spreading, forming a broad crown.

b. Terminal buds 1/8-1/4 inch long, not resinous.

c. Buds and twigs more or less conspicuously white-downy; twigs green. _P. alba_, p. 47.

cc. Buds and twigs not conspicuously white-downy; twigs usually red-brown.

d. Terminal buds about 1/8 inch long, p.u.b.erulous, dusty-looking; lateral buds widely divergent; twigs rather coa.r.s.e. _P. grandidentata_, p. 51.

dd. Terminal buds about 1/4 inch long, glabrous, l.u.s.trous; lateral buds more or less appressed; twigs rather slender. _P.

tremuloides_, p. 49.

bb. Terminal buds 1/2-1 inch long, sticky-resinous.

c. Terminal buds about 1/2 inch long; buds not fragrant; twigs usually yellow, more or less strongly angled. _P. deltoides_, p. 57.

cc. Terminal buds nearly 1 inch long; buds fragrant; twigs usually red-brown and seldom strongly angled. _P.

balsamifera_[E] p. 53. _P. candicans_[E] p. 55.