Michigan Trees Part 38

dd. Leaves finely and abundantly toothed; bark longitudinally white-striped; a bushy tree or shrub.

aa. Leaves compound; twigs usually with whitish bloom. _A.

negundo_, p. 193.

+WINTER KEY TO THE SPECIES OF ACER+

a. Terminal buds usually under 1/4 inch in length.

b. Buds white-woolly; twigs usually with a whitish bloom; opposite leaf-scars meeting; fruit often persistent on the tree until spring. _A. negundo_, p. 193.

bb. Buds not white-woolly; twigs without whitish bloom; opposite leaf-scars not meeting; fruit not persistent on the tree in winter.

c. Buds reddish or greenish; twigs bright red.

d. Twigs strictly glabrous; buds glabrous; spherical flower buds cl.u.s.tered on the sides of the shoot; pith pink; large trees.

e. Twigs rank-smelling when broken; tip of outer bud-scales often apiculate; tips of branches curving upwards; bark separating into long, thin flakes loose at the ends. _A.

saccharinum_, p. 185.

ee. Twigs not rank-smelling when broken; tip of outer bud-scales rounded; tips of branches not conspicuously curving upwards; bark rough-ridged, but seldom forming loose flakes.

_A. rubrum_, p. 187.

dd. Twigs appressed-hairy, at least near the tip; buds somewhat tomentose; spherical flower buds absent; pith brown; shrub or bushy tree. _A. spicatum_, p. 179.

cc. Buds brownish; twigs brownish or grayish.

d. Buds glabrous, or somewhat p.u.b.escent at the apex only; bark dark gray on the trunk. _A. saccharum_, p. 181.

dd. Buds h.o.a.ry-p.u.b.escent; bark sometimes almost black on the trunk. _A. saccharum nigrum_, p. 183.

aa. Terminal buds usually 1/4-1/2 inch in length.

b. Buds reddish; opposite leaf-scars meeting.

c. Buds conspicuously stalked; bud-scales visible, 1 pair; bark longitudinally white-striped; small tree or large shrub. _A.

pennsylvanic.u.m_, p. 177.

cc. Buds not conspicuously stalked; bud-scales visible, 2-3 pairs; bark not white-striped; large tree. _A. platanoides_, p.

189.

bb. Buds bright green; opposite leaf-scars not meeting. _A.

pseudo-plata.n.u.s_, p. 191.

[Ill.u.s.tration: +Striped Maple. Moosewood. Whistlewood+

1. Winter twig, 1.

2. Portion of twig, enlarged.

3. Leaf, 1/2.

4. Staminate flowering branchlet, 1/2.

5. Vertical section of staminate flower, enlarged.

6. Pistillate flowering branchlet, 1/2.

7. Vertical section of pistillate flower, enlarged.

8. Fruit, 3/4.]

+ACERACEAE+

+Striped Maple. Moosewood. Whistlewood+

_Acer pennsylvanic.u.m L._

HABIT.--A small tree at best, more often a large shrub, seldom attaining a height of more than 30 feet, with a short trunk 5-8 inches through.

The striped, upright branches form a rather compact crown.

LEAVES.--Opposite, simple, 5-6 inches long and nearly as broad; 3-lobed above the middle with short, tapering lobes; palmately 3-nerved; sharply doubly serrate; rounded or heart-shaped at the base; glabrous, yellow-green above, paler beneath, turning pale yellow in autumn; petioles stout, grooved.

FLOWERS.--May-June, when the leaves are nearly full grown; usually monoecious; large, bright yellow, bell-shaped, in slender, drooping racemes 4-6 inches long; calyx 5-parted; petals 5; stamens 7-8; ovary downy.

FRUIT.--Ripens in autumn; glabrous, paired samaras in long, drooping, racemose cl.u.s.ters, the wings 3/4 inch long, widely divergent, and marked on one side of each nutlet by a small cavity.

WINTER-BUDS.--Bright red; terminal bud nearly 1/2 inch long, short-stalked, with bud-scales keeled; lateral buds smaller, appressed.

BARK.--Twigs light green, mottled with black, smooth; trunk and branches red-brown, marked longitudinally by broad, pale stripes.

WOOD.--Light, soft, close-grained, pinkish brown, with thick, lighter colored sapwood.

DISTRIBUTION.--Abundant in the Upper Peninsula, extending southward as far as Roscommon County in the Lower Peninsula.

HABITAT.--Cool, rocky or sandy woods, usually in the shade of other trees.

NOTES.--In the Northwoods the green shoots are browsed by deer and moose.

Valued mostly for its aesthetic qualities. Of little or no economic value.

[Ill.u.s.tration: +Mountain Maple+

1. Winter twig, 1.

2. Portion of twig, enlarged.

3. Leaf, 1/2.

4. Flowering branchlet, 1/2.

5. Staminate flower, enlarged.

6. Pistillate flower, enlarged.

7. Fruit, 1.]