[1][G] _Q. macrocarpa_, p. 103.

bb. Twigs glabrous; buds glabrous, or only slightly or partially p.u.b.escent; branches without corky ridges; cup of acorn not conspicuously fringed at the rim.

c. Bark on branches breaking into large, papery scales which curl back; buds pilose above the middle; acorns on p.u.b.escent stems 1-4 inches long. [1] _Q. bicolor_, p. 105.

cc. Bark on branches not breaking into large, papery scales; buds glabrous; acorns sessile or very short-stalked.

d. Bark of trunk ash-gray or nearly white, flaky; acorns maturing in autumn of first season; kernel of nut sweet.

e. Buds conical, acute; bud-scales scarious on the margins; nut white-downy at the apex. [1] _Q. muhlenbergii_, p. 107.

ee. Buds broadly ovoid, obtuse; bud-scales not scarious on the margins; nut not white-downy at the apex. [1] _Q. alba_, p.

101.

dd. Bark of trunk light to dark brown, smoothish or only slightly fissured; acorns maturing in autumn of second season; kernel of nut bitter.

e. Lateral buds widely divergent; bud-scales scarious on the margins; lowermost branches of trees growing in the open not drooping nearly to the ground. [2] _Q. imbricaria_, p. 121.

ee. Lateral buds more or less appressed; bud-scales not scarious on the margins; lowermost branches of trees growing in the open drooping nearly to the ground. [2] _Q. pal.u.s.tris_, p. 111.

aa. Terminal buds usually about 1/4 inch long (slightly smaller in _Q. ellipsoidalis_).

b. Buds conspicuously hairy or tomentose.

c. Buds rusty-hairy, acute at the apex; cup-scales of acorn rusty-tomentose; inner bark of trunk not yellow; shrubby tree, rare in Michigan. [2] _Q. marilandica_, p. 119.

cc. Buds h.o.a.ry-tomentose, obtuse at the apex; cup-scales of acorn h.o.a.ry-p.u.b.escent; inner bark of trunk yellow; large tree, common in Michigan. [2] _Q. velutina_, p. 117.

bb. Buds glabrous, or p.u.b.escent only above the middle.

c. Buds strictly glabrous throughout, l.u.s.trous; inner bark of trunk yellow or whitish.

d. Buds obtuse at the apex; trunk provided with pins or stubs of dead branches near the ground; inner bark of trunk yellow; nut 1/2-3/4 inch long, inclosed for one-third to one-half of its length in a top-shaped cup; kernel of nut yellow. [2] _Q.

ellipsoidalis_, p. 115.

dd. Buds acute at the apex; trunk not provided with pins or stubs of branches near the ground; inner bark of trunk whitish; nut about 1 inch long, inclosed only at the base by a shallow, saucer-shaped cup; kernel of nut white. [2] _Q.

rubra_, p. 109.

cc. Buds pale-p.u.b.escent above the middle, but usually glabrous below, not l.u.s.trous; inner bark of trunk red. [2] _Q.

coccinea_, p. 113.

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

1. Winter twig, 2.

2. Leaf, 1/2.

3. Flowering branchlet, 1/2.

4. Staminate flower, enlarged.

5. Pistillate flower, enlarged.

6. Fruit, 1.]

+f.a.gACEAE+

+White Oak+

_Quercus alba L._

HABIT.--A large tree 60-80 feet high, with a trunk diameter of 2-4 feet; forming a short, thick trunk with stout, horizontal, far-reaching limbs, more or less gnarled and twisted in old age, and a broad, open crown.

LEAVES.--Alternate, simple, 5-9 inches long, about one-half as broad; obovate to oblong; 5-9-lobed, some with broad lobes and shallow sinuses, others with narrow lobes and deep, narrow sinuses, the lobes usually entire; thin and firm; glabrous, bright green above, pale or glaucous beneath; often persistent on the tree through the winter.

FLOWERS.--May, with the leaves; monoecious; the staminate in hairy catkins 2-3 inches long; the pistillate sessile or short-peduncled, reddish, tomentose; calyx campanulate, 6-8-lobed, yellow, hairy; corolla 0; stamens 6-8, with yellow anthers; stigmas red.

FRUIT.--Autumn of first season; sessile or short-stalked acorns; cup with small, brown-tomentose scales, inclosing one-fourth of the nut; nut oblong-ovoid, rounded at the apex, about 3/4 inch long, light brown; kernel sweet and edible.

WINTER-BUDS.--Terminal bud 1/8 inch long, broadly ovoid, obtuse; scales smooth, dark red-brown.

BARK.--Twigs at first bright green, tomentose, later reddish, and finally ashy gray; thick, light gray or whitish on old trunks, shallowly fissured into broad, flat ridges.

WOOD.--Very heavy, strong, hard, tough, close-grained, durable, light brown, with thin, light brown sapwood.

DISTRIBUTION.--Rare in the Upper Peninsula, common in the Lower Peninsula, especially in the lower half.

HABITAT.--Grows well in all but very wet soils, in all open exposures.

NOTES.--Slow and even of growth. Difficult to transplant.

[Ill.u.s.tration: +Bur Oak+

1. Winter twig, 2.

2. Leaf, 1/3.

3. Flowering branchlet, 1/2.

4. Staminate flower, enlarged.

5. Pistillate flower, enlarged.

6. Fruit, 1.]

+f.a.gACEAE+

+Bur Oak+

_Quercus macrocarpa Michx._

HABIT.--A large tree 60-80 feet high, with a trunk 2-4 feet in diameter; great, spreading branches form a broad, rugged crown.