bud-scales often apiculate at the apex; flower-buds clustered on side
spurs.
BARK.--Twigs smooth, red-gray, lustrous; young trunks gray, smooth; old
trunks dark gray, more or less furrowed, separating into thin, loose
scales.
WOOD.--Hard, strong, close-grained, rather brittle, perishable, pale
brown, with thick, lighter colored sapwood.
DISTRIBUTION.--Lower Peninsula south of Saginaw Bay.
HABITAT.--Prefers low, rich bottom-lands, subject to occasional
inundation, but not in swamps.
NOTES.--A rapid grower, adapting itself to a variety of soils. Does not
do well on dry, elevated ground. The first tree to blossom in early
spring.
[Illustration: +Red Maple. Soft Maple+
1. Winter twig, × 1.
2. Portion of twig, enlarged.
3. Leaf, × 1.
4. Fascicle of staminate flowers, × 1.
5. Staminate flower, enlarged.
6. Fascicle of pistillate flowers, × 1.
7. Pistillate flower, enlarged.
8. Fruit, × 3/4.]
+ACERACEAE+
+Red Maple. Soft Maple+
_Acer rubrum L._
HABIT.--A medium-sized tree 40-50 feet high, occasionally in swamps 60-75
feet; trunk 1-3 feet in diameter; upright branches, which form a low,
rather narrow, rounded crown.
LEAVES.--Opposite, simple, 3-4 inches long and nearly as broad; 3-5-lobed
by broad, acute sinuses, the lobes irregularly doubly serrate or
toothed; glabrous, green above, whitish and generally glabrous beneath,
turning bright scarlet in autumn; petioles long, slender.
FLOWERS.--March-April, before the leaves; polygamo-monoecious or
dioecious; in few-flowered fascicles on shoots of the previous year, the
pistillate red, the staminate orange; sepals 4-5; petals 4-5; stamens
5-8; ovary smooth.
FRUIT.--May-June, germinating immediately after reaching the ground;
samaras small, on drooping pedicels 2-4 inches long; wings about 1 inch
long, diverging at about a right angle.
WINTER-BUDS.--Dark red, blunt; terminal bud about 1/8 inch long, with
bud-scales rounded at the apex; flower-buds clustered on side spurs.
BARK.--Twigs bright red, lustrous, becoming smooth and light gray on the
branches; old trunks dark gray, ridged, separating into plate-like
scales.
WOOD.--Heavy, close-grained, not strong, light brown, with thick, lighter
colored sapwood.
DISTRIBUTION.--Throughout the entire state.
HABITAT.--Prefers swamp-lands or banks of streams; rarely found on
hillsides.
NOTES.--A valuable shade and ornamental tree. Sugar has been made in
small quantities from the sap.
[Illustration: +Norway Maple+
1. Winter twig, × 1.
2. Leaf, × 1/2.
3. Raceme of staminate flowers, × 1/2.
4. Staminate flower, enlarged.
5. Raceme of pistillate flowers, × 1/2.
6. Pistillate flower, enlarged.
7. Fruit, × 1/2.]
+ACERACEAE+
+Norway Maple+
_Acer platanoides L._
HABIT.--A tall, handsome tree, with a height of 40-60 feet, and a trunk
diameter of 1-2 feet, having a round, spreading crown of stout branches,
resembling _A. saccharum_. Twigs coarse.
LEAVES.--Opposite, simple, 5-7 inches broad, and almost as long; thin;
5-7-lobed at maturity, lobes remotely coarse-toothed with the teeth
drawn out into filamentous points, separated by rounded, scallop-like
sinuses; glabrous, bright green both sides, turning pale yellow in
autumn; petioles long, slender, exuding a milky juice when cut.
FLOWERS.--May-June, before or with the leaves; dioecious; large,
yellow-green, in erect, short, flat racemes; sepals 5; petals 5; stamens
8.
FRUIT.--Ripens in autumn and germinates the following spring; pendent on
long stalks; large, glabrous, paired samaras, with wings 2 inches long,
diverging by nearly 180°.
WINTER-BUDS.--Yellow-green, red or dull red-brown; terminal bud about 1/4
inch long, broad, short-stalked, with bud-scales strongly keeled;
lateral buds small, appressed; buds exuding a milky juice when cut.
BARK.--Twigs lustrous, light brown to greenish; trunk dark gray, becoming
closely fissured, not scaly.
WOOD.--Moderately heavy, hard, close-grained, whitish or brownish, with
white sapwood.
NOTES.--Exotic from Europe. Extensively planted in cities for its
abundant shade. The roots strike deep and spread laterally, enabling the
tree to hold its own in a city environment. It holds its leaves two
weeks longer in autumn than do our native maples. A rapid grower.
[Illustration: +Sycamore Maple+
1. Winter twig, × 1.
2. Leaf, × 1/2.
3. Flowering branchlet, × 1/2.
4. Staminate flower, enlarged.
5. Perfect flower, enlarged.
6. Fruit, × 1/2.]
+ACERACEAE+
+Sycamore Maple+
_Acer pseudo-platanus L._
HABIT.--A thrifty tree 50-60 feet high, with a trunk diameter of 2-3
feet; the crown roundish, spreading.
LEAVES.--Opposite, simple, 4-7 inches across, and as long as broad;
thick; pentagonally 5-lobed, the lobes more or less ovate, separated by
very narrow, acute sinuses extending about half-way to the midrib, the
lobes coarsely and irregularly blunt-serrate, crenate-serrate, or
slightly lobed; upper surface dark green and shining, somewhat wrinkled,
but paler dull green and glaucous beneath; petioles long, stout.
FLOWERS.--April, before the leaves; polygamo-monoecious; large, greenish
yellow, in pendent racemes of umbellate cymes of about three each;
sepals 5; petals 5; stamens 8, hairy; ovary hairy.
FRUIT.--Ripens in autumn and germinates the following spring; pendent on
long stalks; large, glabrous, paired samaras, with wings 1-1/2 inches
long, diverging at about a right angle.
WINTER-BUDS.--Bright green; terminal bud 1/4-1/2 inch long, ovoid to
subglobose, blunt, with bud-scales more or less keeled; lateral buds
small, divergent.
BARK.--Twigs lustrous, brown or gray, becoming slate colored on the
branches; trunk gray or brownish, smooth or flaking off in short scales.
WOOD.--Moderately heavy, hard, compact, brownish, with white sapwood.
NOTES.--Exotic from Europe. Much planted in our cities, where it is
thrifty, but short-lived. The crown is rather too broad for planting
anywhere except on our widest streets. The leaves last two weeks longer
in autumn than do those of our native maples.
[Illustration: +Boxelder. Ash-leaved Maple+
1. Winter twig, × 1.
2. Leaf, × 1/2.
3. Staminate flowering branchlet, × 1/2.
4. Staminate flower, enlarged.
5. Pistillate flowering branchlet, × 1/2.
6. Pistillate flower, enlarged.
7. Fruit, × 1.]
+ACERACEAE+
+Boxelder. Ash-leaved Maple+
_Acer negundo L._ [_Negundo aceroides Muench._]
HABIT.--A sturdy little tree 30-50 feet high, with a trunk diameter of
1-2 feet. Trunk often divides near the ground into several stout,
wide-spreading branches, forming a broad, unsymmetrical, open crown.
LEAVES.--Opposite, pinnately compound. Leaflets 3-5 in number, 2-4 inches
long, 1-1/2-2-1/2 inches broad; ovate or oval; nearly entire,
irregularly and remotely coarse-toothed above the middle, or sometimes
3-lobed (often giving the leaflet a jagged outline); apex acute, base
variable; glabrous or somewhat pubescent at maturity, with prominent
veins. Petioles slender, 2-3 inches long, the enlarged base leaving
prominent crescent-shaped scars partly surrounding the winter-buds.
FLOWERS.--April, before or with the leaves; dioecious; small,
yellow-green; the staminate in clusters on long, thread-like, hairy
pedicels; the pistillate in narrow, drooping racemes; calyx hairy,
5-lobed; corolla 0; stamens 4-6; ovary pubescent.
FRUIT.--Early summer, but hanging until late autumn or early spring;
narrow, flat, winged samaras, in pairs, clustered in drooping, racemose
clusters.
WINTER-BUDS.--Terminal bud 1/8-1/4 inch long, acute, inclosed in two dull
red scales, often hoary or minutely pubescent; lateral buds obtuse,
appressed.
BARK.--Twigs greenish to purple, glaucous; trunk pale gray or light
brown, deeply cleft into broad ridges.
WOOD.--Light, soft, close-grained, weak, creamy white, with thick, hardly
distinguishable sapwood.
DISTRIBUTION.--Lower Peninsula as far north as Saginaw Bay.
HABITAT.--Banks of streams and borders of swamps. Prefers deep, moist
soil.
NOTES.--Accommodates itself to almost any situation. Easily transplanted.
Much planted for shade and ornament. Fast-growing, but short-lived.
+SUMMER KEY TO THE SPECIES OF AESCULUS+
a. Leaflets usually 5; foliage ill-smelling when bruised; bark
broken into thick plates; prickly bur about 1 inch in
diameter. _A. glabra_, p. 199.
aa. Leaflets usually 7; foliage not ill-smelling when bruised;
bark broken into thin plates; prickly bur about 2 inches in
diameter. _A. hippocastanum_, p. 197.
+WINTER KEY TO THE SPECIES OF AESCULUS+
a. Terminal bud about 2/3 inch long; bud-scales covered with a
glaucous bloom, not conspicuously resinous; bark broken into
thick plates; prickly bur about 1 inch in diameter. _A.
glabra_, p. 199.
aa. Terminal bud 1-1-1/2 inches long; bud-scales conspicuously
sticky-resinous, glistening; bark broken into thin plates;
prickly bur about 2 inches in diameter. _A. hippocastanum_, p.
197.
[Illustration: +Horse-chestnut+
1. Winter twig, × 3/4.
2. Leaf, × 1/6.
3. Leaflet, × 1/2.
4. Flower, × 1.
5. Fruit, × 1/2.]
+SAPINDACEAE+
+Horse-chestnut+
_Aesculus hippocastanum L._
HABIT.--A handsome tree, with a height of 40-60 feet and a trunk diameter
of 1-2 feet, forming a broad, conical crown. The regularly occurring
branches ascend from the trunk at first, gradually bend downwards as
they lengthen, and end in a thick, upturning spray.
LEAVES.--Opposite, digitately compound. Leaflets usually 7, rarely 5, 5-7
inches long, 1-1/2-2-1/2 inches broad; obovate, wedge-shaped at the
base; irregularly and bluntly serrate; thick; rough, dark green above,
paler beneath, turning a rusty yellow in autumn. Petioles long, grooved,
swollen at the base.
FLOWERS.--May-June, after the leaves; polygamo-monoecious; large,
whitish, in showy, upright, terminal thyrses 8-12 inches long; pedicels
jointed, 4-6-flowered; calyx campanulate, 5-lobed; petals 5, white,
spotted with yellow and red, clawed; stamens 7, thread-like, longer than
the petals.
FRUIT.--October; a leathery, globular capsule about 2 inches in diameter,
roughened with short spines; containing 1-3 large, smooth, lustrous,
brown nuts, marked by large, pale scars.
WINTER-BUDS.--Terminal buds 1-1-1/2 inches long, acute, brownish, covered
with glistening, resinous gum; inner scales yellowish, becoming 1-1/2-2
inches long in spring, remaining until the leaves are nearly half grown.
BARK.--Twigs smooth, red-brown; trunk dark brown and broken into thin
plates by shallow fissures; rich in tannin, bitter.
WOOD.--Light, soft, close-grained, weak, whitish, with thin, light brown
sapwood.
NOTES.--A native of Greece, extensively cultivated throughout Europe and
America, where it is a favorite shade tree. A double-flowered variety,
_Aesculus hippocastanum, v. flòre plèno_, which bears no fruit is a
common garden form.
[Illustration: +Ohio Buckeye+
1. Winter twig, × 1.
2. Leaf, × 1/6.
3. Leaflet, × 1/2.
4. Flower, × 2.
5. Fruit, × 1/2.
6. Nut, × 1/2.]
+SAPINDACEAE+
+Ohio Buckeye+
_Aesculus glabra Willd._
HABIT.--A medium-sized tree 30-50 feet in height, with a trunk not over 2
feet in diameter; usually much smaller; slender, spreading branches,
forming a broad, rounded crown; twigs thick.
LEAVES.--Opposite, digitately compound. Leaflets usually 5, rarely 7, 3-6
inches long, 1-1/2-2-1/2 inches broad; ovate or oval, gradually narrowed
to the entire base; irregularly and finely serrate; glabrous,
yellow-green above, paler beneath, turning yellow in autumn. Petioles
4-6 inches long, slender, enlarged at the base. Foliage ill-smelling
when bruised.
FLOWERS.--April-May, after the leaves; polygamo-monoecious; small,
yellow-green, in terminal panicles 5-6 inches long and 2-3 inches broad,
more or less downy; pedicels 4-6-flowered; calyx campanulate, 5-lobed;
petals 4, pale yellow, hairy, clawed; stamens 7, with long, hairy
filaments.
FRUIT.--October; a thick, leathery, prickly capsule, about 1 inch in
diameter, containing a single large, smooth, lustrous, brown nut. A
large pale scar gives the name "Buckeye".
WINTER-BUDS.--Terminal buds 2/3 inch long, acute, resinous, brownish;
inner scales yellow-green, becoming 1-1/2-2 inches long in spring and
remaining until the leaves are nearly half grown.
BARK.--Twigs smooth, red-brown, becoming ashy gray; old trunks densely
furrowed and broken into thick plates; ill-smelling when bruised.
WOOD.--Light, soft, close-grained, weak, whitish, with thin, light brown
sapwood.
NOTES.--A native of the Mississippi River Valley. Occasionally planted in
southern Michigan for ornamental purposes, but is less popular than the
Horse-chestnut.
[Illustration: +Basswood+
1. Winter twig, × 1.
2. Leaf, × 1/2.
3. Cyme of flowers, with its bract, × 1/2.
4. Flower, with two petals, petaloid scales
and stamens removed, enlarged.
5. Stamen, enlarged.
6. Fruit, × 1/2.]
+TILIACEAE+
+Basswood+
_Tilia americana L._
HABIT.--A tree usually 60-70 feet high, with a tall, straight trunk 2-4
feet in diameter; numerous slender branches form a dense, ovoid or
rounded crown.
LEAVES.--Alternate, simple, 5-6 inches long, 3-4 inches broad; obliquely
heart-shaped; coarsely serrate; thick and firm; glabrous, dull dark
green above, paler beneath; petioles slender, 1-2 inches long.
FLOWERS.--June-July, after the leaves; perfect, regular; yellowish white,
downy, fragrant; borne on slender pedicels in loose, drooping cymes, the
peduncle attached for half its length to a narrow, oblong, yellowish
bract; sepals 5, downy; petals 5, creamy white; stamens numerous, in 5
clusters; ovary 5-celled; stigma 5-lobed.
FRUIT.--October; globose, nut-like, woody, gray, tomentose, about the
size of peas.
WINTER-BUDS.--Terminal bud absent; lateral buds ovoid, acute, often
lopsided, smooth, dark red, 1/4 inch long.
BARK.--Twigs smooth, reddish gray, becoming dark gray or brown; dark gray
and smooth on young stems, on old trunks thick, deeply furrowed into
broad, scaly ridges.
WOOD.--Light, soft, close-grained, tough, light red-brown, with thick
sapwood of nearly the same color.
DISTRIBUTION.--Common in most parts of the Lower Peninsula, frequent in
the Upper Peninsula.
HABITAT.--Prefers rich, well-drained, loamy soils.
NOTES.--Rapid in growth. Easily transplanted. Recommended for street and
ornamental planting.
+SUMMER KEY TO THE SPECIES OF CORNUS+
a. Leaves mostly alternate; branches usually greenish; flowers
not surrounded by large petal-like bracts; fruit globular,
blue, borne many in loose clusters. _C. alternifolia_, p. 207.
aa. Leaves opposite; branches usually reddish or yellowish;
flowers surrounded by large petal-like bracts; fruit ovoid,
scarlet, borne in close clusters of 3-4. _C. florida_, p. 205.
+WINTER KEY TO THE SPECIES OF CORNUS+
a. Leaf-scars mostly alternate; buds light brown; branches
usually greenish. _C. alternifolia_, p. 207.
aa. Leaf-scars opposite; buds greenish; branches usually
reddish or yellowish. _C. florida_, p. 205.
[Illustration: +Flowering Dogwood. Dogwood. Boxwood+
1. Winter twig, with leaf buds, × 1.
2. Portion of twig, enlarged.
3. Winter twig, with flower bud, × 1.
4. Leaf, × 1/2.
5. Flowering branchlet, × 1/2.
6. Flower, enlarged.
7. Fruit, × 1.]
+CORNACEAE+
+Flowering Dogwood. Dogwood. Boxwood+
_Cornus florida L._
HABIT.--A bushy tree with a height of 15-30 feet and a short trunk 8-12
inches in diameter; slender, spreading branches form a flat-topped
crown.
LEAVES.--Opposite, closely clustered at the ends of the branchlets,
simple, 3-5 inches long, 2-3 inches broad; ovate to elliptical;
obscurely wavy-toothed; thick and firm; bright green, covered with
minute, appressed hairs above, pale and more or less pubescent beneath,
turning bright scarlet in autumn; petioles short, grooved.
FLOWERS.--May, with the leaves; perfect; greenish; in dense clusters,
surrounded by 4 large, white or pinkish, petal-like bracts (often
mistaken for the corolla), borne on short, stout peduncles; calyx
4-lobed, light green; petals 4, yellow-green; stamens 4, alternate with
the petals; ovary 2-celled.
FRUIT.--October; an ovoid, scarlet drupe, borne in close clusters of 3-4;
flesh is bitter.
WINTER-BUDS.--Leaf-buds narrow-conical, acute, greenish; flower-buds
spherical or vertically flattened, grayish.
BARK.--Twigs pale green, becoming red or yellow-green their first winter,
later becoming light brown or red-gray; red-brown or blackish on the
trunk, often separating into quadrangular, plate-like scales.
WOOD.--Heavy, hard, strong, tough, close-grained, brownish, with thick,
lighter colored sapwood.
DISTRIBUTION.--Southern Michigan as far north as the Grand-Saginaw
Valley.
HABITAT.--Prefers rich, well-drained soil, usually under the shade of
other trees.
NOTES.--A valuable species for ornamental purposes. Rather slow of
growth.
[Illustration: +Blue Dogwood. Alternate-leaved Dogwood+
1. Winter twig, × 1.
2. Portion of twig, enlarged.
3. Leaf, × 3/4.
4. Flowering branchlet, × 1/2.
5. Flower, enlarged.
6. Fruiting branchlet, × 1/2.]
+CORNACEAE+
+Blue Dogwood. Alternate-leaved Dogwood+
_Cornus alternifolia L. f._
HABIT.--A small tree or large shrub reaching a height of 25-30 feet and a
trunk diameter of 6-8 inches; more often smaller than this. The long,
slender branches are arranged in irregular whorls, forming flat,
horizontal tiers, giving the tree a storied effect.
LEAVES.--Mostly alternate and clustered at the ends of the branchlets;
simple, 3-5 inches long, 2-1/2-3 inches broad; oval or ovate,
long-pointed, wedge-shaped at the base; obscurely wavy-toothed; thin;
dark green, nearly glabrous above, paler and covered with appressed
hairs beneath, turning yellow and scarlet in autumn; petioles slender,
grooved, hairy, with clasping bases.
FLOWERS.--May-June, after the leaves; perfect; borne on slender pedicels
in many-flowered, irregular, open cymes from the season's shoots; calyx
cup-shaped, obscurely 4-toothed, covered with fine, silky, white hairs;
petals 4, cream colored; stamens 4; ovary 2-celled.
FRUIT.--October; a globular, blue-black drupe, borne in loose,
red-stemmed clusters; flesh bitter.
WINTER-BUDS.--Leaf-buds small, acute, light brown; flower-buds spherical
or vertically flattened.
BARK.--Twigs greenish or reddish, becoming smooth, dark green; thin, dark
red-brown and shallowly fissured on the trunk.
WOOD.--Heavy, hard, close-grained, red-brown, with thick, lighter colored
sapwood.
DISTRIBUTION.--Scattered throughout both peninsulas.
HABITAT.--Prefers moist, well-drained soil on the borders of streams and
swamps, often in the shade of other trees.
NOTES.--Hardy throughout the state. Easily transplanted. The only
_Cornus_ with alternate leaves and branches.
[Illustration: +Black Gum. Pepperidge+
1. Winter twig, × 1.
2. Portion of twig, enlarged.
3. Leaf, × 3/4.
4. Staminate flowering branchlet, × 1/2.
5. Staminate flower, enlarged.
6. Pistillate flowering branchlet, × 1/2.
7. Pistillate flower, enlarged.
8. Fruit, × 1/2.]
+CORNACEAE+
+Black Gum. Pepperidge+
_Nyssa sylvatica Marsh._ [_Nyssa multiflora Wang._]
HABIT.--A medium-sized tree 40-50 feet high, with a trunk diameter of 1-2
feet, forming a rounded to cylindrical crown of slender, spreading,
pendulous branches and a stiff, flat spray.
LEAVES.--Alternate, simple, 2-5 inches long, one-half as broad;
oblong-obovate to oval; entire, or sometimes wavy-margined; thick and
firm; very lustrous and dark green above, pale and often hairy beneath,
turning bright scarlet, on the upper surface only, in autumn; petioles
short.
FLOWERS.--May-June, with the leaves; polygamo-dioecious; greenish; borne
on slender, downy peduncles; the staminate slender-pedicelled, in
many-flowered heads; the pistillate sessile, in several-flowered
clusters; calyx cup-shaped, 5-toothed; petals 5; stamens 5-10; stigma
stout, terete, recurved.
FRUIT.--October; fleshy drupes, ovoid, blue-black, about 1/2 inch long,
sour, in clusters of 1-3.
WINTER-BUDS.--1/8-1/4 inch long, ovoid, obtuse, dark red.
BARK.--Twigs greenish or light brown, smooth or often downy, becoming
smooth, dark red-brown; thick, red-brown on old trunks, deeply furrowed.
WOOD.--Heavy, soft, strong, very tough, difficult to split, not durable
in contact with the soil, pale yellow, with thick, whitish sapwood.
DISTRIBUTION.--Frequent in the southern half of the Lower Peninsula. Has
been reported as far north as Manistee.
HABITAT.--Prefers the borders of swamps and low, wet lands. Rarely
flourishes in exposed situations.
NOTES.--Of great ornamental value. Not easily transplanted. Pith of twigs
with thin, transverse partitions.
+SUMMER KEY TO THE SPECIES OF FRAXINUS+
a. Lateral leaflets sessile. _F. nigra_, p. 221.
aa. Lateral leaflets petioluled.
b. Twigs, petioles and lower sides of leaves pubescent. _F.
pennsylvanica_, p. 215.
bb. Twigs, petioles and lower sides of leaves essentially
glabrous.
c. Twigs prominently 4-angled. _F. quadrangulata_, p. 219.
cc. Twigs terete.
d. Lower sides of leaves essentially of the same color as the
upper; leaflet-margins rather finely sharp-serrate. _F.
pennsylvanica lanceolata_, p. 217.
dd. Lower sides of leaves paler than the upper;
leaflet-margins entire or obscurely serrate. _F. americana_,
p. 213.
WINTER KEY TO THE SPECIES OF FRAXINUS
a. Twigs prominently 4-angled; fruit falling in early autumn.
_F. quadrangulata_, p. 219.
aa. Twigs terete; fruit often persistent on the tree until
mid-winter or the following spring.
b. Buds rusty-tomentose; twigs more or less downy. _F.
pennsylvanica_, p. 215.
bb. Buds not tomentose; twigs not downy.
c. Terminal bud black or nearly so, showing 3 pairs of scales
in cross-section; bud-scales apiculate at the apex; samaras
with broad wings, the seed portion flattish; bark flaky,
rubbing off on the hand. _F. nigra_, p. 221.
cc. Terminal bud brownish, showing 4 pairs of scales in
cross-section; bud-scales rounded at the apex; samaras with
narrow wings, the seed portion terete; bark ridged, not flaky
and rubbing off on the hand.
d. Upper margin of leaf-scars deeply concave. _F. americana_,
p. 213.
dd. Upper margin of leaf-scars not concave, but straight
across or projecting upward. _F. pennsylvanica lanceolata_, p.
217.
[Illustration: +White Ash+
1. Winter twig, × 1.
2. Leaf, × 1/4.
3. Staminate flowering branchlet, × 1/2.
4. Staminate flower, enlarged.
5. Pistillate flowering branchlet, × 1/2.
6. Pistillate flower, enlarged.
7. Fruit, × 1.]
+OLEACEAE+
+White Ash+
_Fraxinus americana L._
HABIT.--A large tree 50-75 feet high, with a trunk diameter of 2-3 feet;
forming an open, pyramidal crown of long, slender, lateral branches and
a stout, rather sparse spray.
LEAVES.--Opposite, pinnately compound, 8-12 inches long. Leaflets usually
7-9, 3-5 inches long, 1-2 inches broad; short-stalked; ovate to
oblong-lanceolate; entire or obscurely serrate; thick and firm;
glabrous, dark green above, paler beneath. Petioles glabrous, stout,
grooved.
FLOWERS.--May, before the leaves; dioecious; borne in loose panicles on
shoots of the previous season; calyx campanulate, 4-lobed; corolla 0;
stamens 2, rarely 3; ovary 2-celled.
FRUIT.--August-September, persistent on the branches until mid-winter or
the following spring; samaras 1-2 inches long, in crowded, drooping,
paniculate clusters 6-8 inches long.
WINTER-BUDS.--Short, rather obtuse; bud-scales apiculate, keeled, 4
pairs, rusty-brown.
BARK.--Twigs at first dark green, becoming gray or light brown, often
covered with a glaucous bloom; gray, deeply furrowed into firm, narrow,
flattened ridges on the trunk.