June when the leaves are nearly fully grow r n, on slender pedicels ?'~ l n g> m slender
drooping long-stemmed racemes 4 '-6' in length, the staminate and pistillate usually in
different racemes on the same plant; sepals linear-lanceolate to obovate, \' long and a little
shorter and narrower than the obovate petals; stamens 7-8, shorter than the petals in the
staminate flower, rudimentary in the pistillate flower; ovary purplish brown, glabrous, in
the staminate flower reduced to a minute point; styles united nearly to the top, with
spreading recurved stigmas. Fruit in long drooping racemes, glabrous, with thin spreading
w r ings f ' long, and marked on one side of each nutlet by a small cavity; seeds \ f long, dark
red-brown, and slightly rugose.
A tree, 30-40 high, with a short trunk 8'-10' in diameter, small upright branches, and
slender smooth branchlets pale greenish yellow at first, bright reddish brown during their
first winter, and at the end of two or three years striped like the trunk with broad pale
lines; or often much smaller and shrubby in habit. Winter-buds: the terminal conspicu-
ously stipitate, sometimes almost \' long, much longer than the axillary buds, covered by
two thick bright red spatulate boat-shaped scales prominently keeled on the back, the
inner scales green and foliaceous, becoming l|'-2' long, \' wide, pubescent, and bright yel-
low or rose color. Bark of the trunk \'-% thick, reddish brown, marked longitudinally by
broad pale stripes, and roughened by many oblong horizontal excrescences. Wood light,
soft, close-grained, light brown, with thick lighter colored sap wood of 30-40 layers of annual
Distribution. Usually in the shade of other trees, often forming in northern New
England a large part of their shrubby undergrowth; shores of Ha-Ha Bay, Quebec, west-
ward along the shores of Lake Ontario and the islands of Lake Huron to northern Wiscon-
sin, and southward through the Atlantic states and along the Appalachian Mountains to
northern Georgia; ascending to altitudes of 5000; common in the north Atlantic states,
especially in the interior and elevated regions; of its largest size on the slopes of the Big
Smoky Mountains, Tennessee, and of the Blue Ridge in North and South Carolina.
Sometimes cultivated as an ornamental tree in the northern states, and occasionally in
5. Acer macrophyllum Pursh. Broad-leaved Maple.
Leaves more or less cordate at the broad base, deeply 5-lobed by narrow sinuses acute in
the bottom, the lobes acute or acuminate, the terminal lobe often 3-lobed, the others usually
furnished with small lateral lobules, the lower lobes much smaller than the others, promi-
nently 3-5-nerved, puberulous when they unfold, especially on the upper surface along
the principal veins, and at maturity subcoriaceous, dark green and lustrous on the upper
surface, pale on the lower surface, 8'-12' in diameter; turning in the autumn bright orange
oolor before falling; petioles stout, 10'-12' in length, with enlarged bases united and encir-
cling the stem and often furnished on the inside with small tufts of white hairs. Flowers
bright yellow, fragrant, \' long, on slender pubescent often branched pedicels '-f ' in length,
the staminate and pistillate together in graceful pendulous slightly puberulous racemes
4 '-6' long, appearing in April and May after the leaves are fully grown; sepals petaloid, obo-
vate, obtuse and a little longer and broader than the spatulate petals; stamens 9-10, with
long slender filaments hairy at base, exserted in the staminate flower and included in the
pistillate flower, and orange-colored anthers; ovary hoary-tomentose, reduced in the stam-
inate flower to a minute point; styles united at base only; stigmas long and exserted. Fruit
688 TREES OF NORTH AMERICA
fully grown by the 1st of July and ripening late in the autumn; nutlets covered with long
pale hairs, their wings l' long, \' wide, slightly divergent and glabrous with the exception
of a few hairs on the thickened edge; seeds dark-colored, rugose and pitted, \' long.
A tree, 80-100 high, with a tall straight trunk 2-3 in diameter, stout often pendulous
branches forming a compact handsome head, and stout branchlets smooth and pale green
at first, becoming bright green or dark red in their first winter, covered more or less thickly
with small longitudinal white lenticels, and in their second summer gray or grayish brown.
Winter-buds obtuse; terminal \' long, with short broad slightly spreading dark red ciliate
outer scales rounded on the back, those of the inner ranks green and foliaceous, and at
maturity \\' long, colored and puberulous; axillary buds minute. Bark of the trunk |'-f '
thick, brown faintly tinged with red or bright reddish brown, deeply furrowed and broken
on the surface into small square plate-like scales. Wood light, soft, not strong, close-
grained, rich brown tinged with red, with thick lighter colored often nearly white sapwood
of 60-80 layers of annual growth; more valuable than the wood produced by other decidu-
ous-leaved trees of western North America, and in Washington and Oregon used in the
interior finish of buildings, for furniture, and for axe and broom-handles.
Distribution. Banks of streams or on rich bottom-lands or the rocky slopes of mountain
valleys; coast of Alaska south of latitude 55 north, southward along the islands and coast
of British Columbia, through Washington and Oregon west of the Cascade Mountains,
and southward along the coast ranges and the western slopes of the Sierra Nevada to the
San Bernardino Mountains, and to Hot Spring Valley, San Diego County, California; on
the Sierra Nevada usually between altitudes of 2000 and 5000 and on the southern moun-
tains rarely above 3000; most abundant and of its largest size in the humid climate and
rich soil of the bottom-lands of southwestern Oregon, forming extensive forests; in Cali-
fornia usually much smaller, especially on the coast ranges.
Generally planted in the Pacific States for shade and as a street tree, and occasionally
in the Eastern States as far north as Long Island, New York, and in western Europe; not
hardy in Massachusetts.
6. Acer saccharum Marsh. Sugar Maple. Rock Maple.
Leaves rarely in whorls of 3, heart-shaped by a broad sinus, truncate or sometimes
cuneate at base, 3-5-lobed, the lobes usually acute sparingly sinuate-toothed usually
3-lobulate at apex, with 3-5 conspicuous nerves, and reticulate veinlets, when they un-
fold coated below with pale pubescence, glabrous or more or less pubescent on the nerves
below (var. Schneckii Rehd.) and at maturity, 4'-5' in diameter, often rather coriaceous,
dark green and opaque on the upper surface, green or pale (var. glabrum Sarg.) on the lower
surface; turning in the autumn brilliant shades of deep red, scarlet and orange or clear yel-
low ; petioles slender, glabrous, H'-3' in length. Flowers appearing with the leaves on slen-
der more or less hairy pedicels f '-3' long, in nearly sessile umbel-like corymbs from terminal
leaf-buds and lateral leafless buds, the staminate and pistillate in the same or in separate
clusters on the same or on different trees; calyx broad-campanulate, o-lobed by the partial
union of the obtuse sepals, greenish yellow, hairy on the outer surface; corolla 0; stamens
7-8, w r ith slender glabrous xfilaments tw 7 ice as long as the calyx in the staminate flower
and much shorter in the pistillate flower; ovary obtusely lobed, pale green, covered with long
scattered hairs, in the staminate flower reduced to a minute point; styles united at base
only, with 2 long exserted stigmatic lobes. Fruit ripening in the autumn, glabrous, with
broad thin and usually divergent wings ^'-1'long; seeds smooth, bright red-brown, \' long.
A tree, 100-120 high, with a trunk often 3-4 in diameter, rising sometimes in the
forest to the height of 60-70 without branches, or in open situations developing 8-10
from the ground stout upright branches forming while the tree is young a narrow egg-shaped
head, ultimately spreading into a broad round-topped dome often 70-80 across, and
slender glabrous branchlets green at first, becoming reddish brown by the end of their first
season, lustrous, marked by numerous large pale oblong lenticels, and in their second
winter pale brown tinged with red. Winter-buds acute, \' long, with purple slightly puber-
ulous outer scales, and inner scales becoming 1 \' long, narrow-obovate, short-pointed at apex,
thin, pubescent, and bright canary yellow. Bark of young stems and of large branches
pale, smooth or slightly fissured, becoming on large trunks '-f thick and broken into
deep longitudinal furrows, the light gray-brown surface separating into small plate-like
scales. Wood heavy, hard, strong, close-grained, tough, light brown tinged with red, with
thin sapwood of 30-40 layers of annual growth; largely used for the interior finish of build-
ings, especially for floors, in the manufacture of furniture, in turnery, shipbuilding, for
shoe-lasts and pegs, and largely as fuel. Accidental forms with the grain curled and con-
torted, known as curly maple and bird's-eye maple, are common and are highly prized in
cabinet-making. The ashes of the wood are rich in alkali and yield large quantities of
potash. Maple sugar is principally made from the sap of this tree.
Distribution. Newfoundland and Nova Scotia, westward to the Lake of the Woods,
Ontario, and southward through eastern Canada and the northern states, and along the
Appalachian Mountains to northern Georgia; in central Alabama and Mississippi, and
westward in the United States to Minnesota, northeastern South Dakota (coulees of Little
Minnesota River, Roberts County), central and northwestern Iowa, eastern Kansas,
central Oklahoma, and eastern Louisiana; most abundant northward; ascending in North
Carolina the Alleghany Mountains to altitudes of 3000; the var. glabrum rare and local
in the north from Prince Edwards Island and Lake St. John, Quebec, to Iowa and south-
ward to Pennsylvania, Ohio and central Tennessee; more abundant southward; apparently
the only form but not common in South Carolina, Alabama, Mississippi, Louisiana and
southern Arkansas; the var. fjjchneckii with leaves glaucous or glaucescent below and more
or less densely pubescent with spreading hairs, on the under side of the midrib and veins
and on the petioles, southern Indiana and Illinois to western Kentucky and western and
middle Tennessee, northwestern Georgia (near Rome, Floyd County), and to eastern
Missouri southward to Williamsville, Wayne County.
Commonly planted as a shade and ornamental tree in the northern states.
More distinct are the following varieties:
Acer saccharum var. Rugelii Rehd.
Leaves thick, 3'-5' long and 4'-6' wide, pale and glabrous below, 3-lobed by broad
rounded sinuses, rounded or slightly cordate at base, the lobes long-acuminate, usually en-
tire, the middle lobe occasionally slightly undulate, the lateral lobes spreading, sometimes
furnished near the base with a short acute lobule.
TREES OF NORTH AMERICA
Distribution. Southeastern Ohio to western Pennsylvania (Kittaning, Armstrong
County) and eastern and middle Tennessee, and to southern Ontario, the southern penin-
sula of Michigan, eastern and central Indiana, southern Illinois, eastern Missouri and
northwestern Arkansas (Eureka Springs, Carroll County); rare and local in its extreme
form; its 3-lobed leaves sometimes appearing on upper branches of trees bearing on lower
branches leaves of the typical Sugar Maple.
Acer saccharum var. sinuosum Sarg.
Acer sinuosum Rehd,
Leaves suborbicular, broader than long, 3-5-lobed with short triangular-ovate to tri-
angular-oblong obtuse lobes, entire or on vigorous shoots occasionally dentate, usually
broad-cordate at base, often with the nerves of the two lateral lobes projecting into the
broad sinus and forming its base, when they unfold glabrous and purplish above, loosely
hairy below, soon glabrous, and at maturity dark yellow-green and lustrous on the upper
surface, pale, reticulate-venulose and glabrous except in the axils of the principal veins on
the lower surface. 3-o-nerved, usually not more than If long, occasionally up to 2f ' long
and 3' wide; petioles slender, glabrous, f -If in length. Flowers appearing with the leaves,
on slender glabrous pedicels, f-li' long, in 3-8-flowered nearly sessile corymbs; calyx broad-
campanulate or cupulate, with short semiorbicular lobes ciliate on the margins; petals 0;
stamens usually 6, with slender filaments longer than the calyx of the staminate flower; style
divided to below the middle, with two spreading stigmas. Fruit glabrous, with long and
broad almost horizontally spreading nutlets, convex, smooth, pale yellow-brown, the wing
A tree, rarely more than 20 high with a short trunk 8'-10' in diameter, small branches
forming an open irregular head, and slender glabrous branchlets light green above when
they first appear, becoming pale red-brown and marked by pale lenticels during their first
season and ultimately dull gray-brown. Bark of the trunk smooth, pale gray. Winter-
buds small, obtuse, covered with dark brown scales, those of the inner ranks accrescent,
linear-oblong, scarlet or pink, up to \\' in length when fully grown.
Distribution. Edwards Plateau of western Texas, banks and bluffs of Cibelo Creek,
near Boerne, Kendall County, on the rocky banks of upper Saco Creek, Bandera County,
and at the base of a high limestone bluff near Utopia, TJvalde County; rare and local.
7. Acer floridanum Pax. Sugar Maple.
Leaves rounded, truncate or slightly cordate at the broad base, 3-5-lobed, with short obtuse
or acute entire or lobulate lobes, when they unfold sparingly hairy on the upper surface
and hoary-tomentose on the lower surface, and at maturity thin, dark green and lustrous
above, pale or glaucescent and pubescent below, If -3' in diameter, and prominently
3-5-nerved, with stout spreading lateral veins and conspicuous reticulate veinlets; turning
yellow and scarlet in the autumn before falling; petioles slender, glabrous, or pubescent
generally becoming glabrous, lf-3' in length, with an enlarged base nearly encircling the
branchlet. Flowers appearing with the leaves on slender elongated sparingly hairy ul-
timately glabrous or villose-tomentose (var. villipes Rehd.) pedicels, in many-flowered
drooping nearly sessile corymbs; calyx campanulate, yellow, about f long, persistent under
the fruit, the short lobes ciliate on the margins with long pale hairs; corolla 0. Fruit green,
TREES OF NORTH AMERICA
sparingly villose until fully grown, usually becoming glabrous, with spreading occasionally
erect wings f '-' long; seeds smooth, bright red-brown, about 1' long.
A tree, occasionally 50-60 high, with a trunk rarely 3 in diameter, small erect and
spreading branches, and slender glabrous or more or less densely villose-tomentose (var.
villipes Rehdr.) branchlets, light green when they first appear, becoming rather light red-
brown during their first season, and covered with minute pale lenticels; usually smaller.
Winter-buds obtuse, about |-' long, with dark chestnut-brown obtuse scales and bright
rose-colored linear-spatulate inner scales often 1' long when fully grown. Bark of the trunk
thin, smooth, pale, becoming near the base of old trees thick, dark, and deeply furrowed.
Distribution. River banks and low wet woods, southeastern Virginia (near McKinney,
Dinwiddie County, W. W. Ashe), valley of the Roanoke River near Weldon, Halifax
County, North Carolina, and southward to southern Georgia and western Florida to La-
fayette County; near Selma, Dallas County, Alabama; West Feliciana Parish and through
western Louisiana to eastern Texas (Harrison and St. Augustine Counties), and southern
Arkansas (Fulton, Hempstead County) ; the var. fillipes near Raleigh, Walker County,
North Carolina, Calhoun Falls, Abbeville County, South Carolina, Shell Bluff on the
Savannah River, Burke County, Cuthbert, Randolph County, and Columbus, Muscogee
County, Georgia; River Junction, Gadsden County, Florida, and on the San Luis Moun-
tains, southern New Mexico (A. brachypterum Woot. & Stanl.).
Sometimes planted as a shade-tree; the prevailing tree in the streets and squares of
Raleigh, North Carolina.
8. Acer grandidentatum Nutt. Sugar Maple.
Leaves cordate or truncate at base, 3-lobed by broad shallow sinuses, the lobes acute or
obtuse, entire or slightly lobulate, sparingly hairy on the upper surface and thickly coated
with dense paletomentum on the lower surface when they unfold, and at maturity thick and
firm, dark green and lustrous above, pale and pubescent below, especially on the stout nerves
and veins, or rarely glabrous, 2'-5' in diameter; turning in the autumn before falling yellow
and scarlet; petioles stout, l'-2' in length, glabrous, often red after midsummer, encircling
the branchlet with their large base villose on the inner surface. Flowers appearing with
the leaves on long slender drooping villose pedicels, in short-stalked corymbs; calyx cam-
panulate, yellow, sparingly hairy with long pale hairs, about j' long, with broad rounded
lobes, often persistent under the fruit; corolla 0; stamens 7 or 8, much longer than the calyx,
in the pistillate flower shorter than the calyx; ovary usually glabrous, with long spreading
stigmatic lobes, rudimentary in the staminate flower. Fruit often rose-colored at mid-
summer, green at maturity, glabrous or rarely sparingly hairy, with spreading or erect
wings 2'"!' long; seeds smooth, light red-brown, about \' long.
A tree, occasionally 30-40 high, with a trunk 8'-10' in diameter, stout usually erect
branches, and slender glabrous bright red branchlets marked by numerous small pale
lenticels and nearly encircled by the narrow leaf-scars, with conspicuous bands of long pale
hairs in their axils. Winter-buds acute or acuminate, about -fa' long, bright red-brown,
with puberulous-ciliate outer scales and obovate apiculate inner scales sometimes \' long
when fully grown. Bark of the trunk thin, dark brown, separating on the surface into
plate-like scales. Wood heavy, hard, close-grained, bright brown or nearly white, with
thick sap wood.
Distribution. Banks of mountain streams usually at altitudes of 5000-6000 C above
the sea; on the Salt River Mountains, western Wyoming; valley of the Columbia River in
northern Montana, southeastern Idaho (Pocatello, Oneida County), Wasatch Mountains,
Utah, mountains of Arizona and of southern New Mexico; on the Guadalupe Mountains,
western Texas, and on the Wichita Mountains, southwestern Oklahoma (G. W. Stevens) ; in
Coahuila; rare and local.
Occasionally cultivated; hardy in the Arnold Arboretum.
9. Acer nigrum Michx. Black Maple.
Leaves generally 3 or occasionally 5-lobed, with abruptly short-pointed acute or acu-
minate lobes, undulate and narrowed from broad shallow sinuses and rarely furnished with
short lateral spreading lobules, cordate at base with a broad sinus usually more or less closed
by the approximation or imbrication of the basal lobes, occasionally 3-lobed with a broad
long-acuminate nearly entire terminal lobe, and rounded or slightly cordate at base (var.
Palmeri Sarg.), covered below when they unfold with hoary tomentum and above with
caducous pale hairs, and at maturity thick and firm in texture, dull green on the upper
surface, yellow-green and soft-pubescent, especially along the yellow veins on the lower
surface, and 5 '-6' long and wide, with drooping sides; turning bright clear yellow in the
autumn; petioles stout, tomentose or pubescent, sometimes becoming glabrous at maturity,
usually pendent, 3'-5' in length, much enlarged at base, frequently nearly inclosing the
buds, in falling leaving narrow scars almost encircling the branchlet and furnished in their
axils with tufts of long pale hairs; stipules triangular and dentate or foliaceous, sessile or
stipitate, oblong, acute, tomentose or pubescent, sometimes slightly lobed, frequently
H' long. Flowers yellow, about ' long, on slender hairy pedicels 2^ '-3' long, in many-
694 TREES OF NORTH AMERICA
flowered nearly sessile umbel-like corymbs, the staminate and pistillate in separate or in
the same cluster on the same or on different trees; calyx broad-campanulate, 5-lobed by
the partial union of the sepals, pilose on the outer surface near the base; corolla 0; stamens
7 or 8, with slender glabrous filaments, in the staminate flower nearly twice as long as the
calyx and in the pistillate flower shorter than the calyx; ovary obtusely lobed, pale green,
covered with long scattered hairs, minute in the sterile flower. Fruit glabrous, with con-
vergent or wide-spreading wings \'-\' long; seeds smooth, bright red-brown, \' long.
A tree, sometimes 80 high, with a trunk frequently 3 in diameter, stout spreading or
often erect branches, and stout branchlets marked by oblong pale lenticels, orange-green
and pilose with scattered pale caducous hairs when they appear, orange or orange-brown
and lustrous during their first year, becoming dull pale gray-brown the following season.
Winter-buds sessile, ovoid, acute, ' long, with dark red-brown acute scales hoary-pubes-
cent on the outer surface and often slightly ciliate on the margins, and yellow puberulous
inner scales, |'-1' long at maturity. Bark of young stems and of the branches thin,
smooth, pale gray, becoming on old trunks thick, deeply furrowed, and sometimes almost
Distribution. Valley of the St. Lawrence River in the neighborhood of Montreal,
Quebec, southward to the valley of Cold River, New Hampshire, through western Vermont
and Massachusetts and northwestern Connecticut (near Salisbury, Litchfield County),
and westward through northern and western New York, southern Ontario, Ohio, the
southern peninsula of Michigan, Indiana, Illinois, and Iowa to southeastern Minnesota,
northeastern South Dakota, western and southern Missouri, eastern Kansas, and south-
ward through western Pennsylvania, West Virginia and eastern Kentucky; comparatively
rare near Montreal and in New England, more abundant farther west; almost entirely re-
placing Acer saccharum in Iowa, and the only Sugar Maple of South Dakota ; easily dis-
tinguished in summer by its heavy drooping leaves, and at all seasons of the year by the
orange color of the branchlets; the var. Palmeri in a single grove at Tunnel Hill, Johnson
County, Illinois; southern Indiana (Shelby, Putnam and Lawrence Counties), and in Clark,
Jackson and Dunklin Counties, Missouri; rare and local.
Occasionally planted in the region where it grows naturally as a shade-tree.
10. Acer leucoderme Small. Sugar Maple.
Leaves usually truncate or slightly cordate at base, more or less deeply divided into
3-5 acute caudate-acuminate lobes coarsely and sinuately dentate or undulate, when they
unfold coated below with long matted pale caducous hairs, and at maturity thin, dark
yellow-green above, bright yellow-green and pilose-pubescent below, 2'-3^' in diameter;
often turning in the autumn bright scarlet on the upper surface before falling; petioles
slender, glabrous, I'-l^' in length. Flowers yellow, about f long, on slender, glabrous
pedicels, in nearly sessile clusters; calyx campanulate, glabrous or slightly villose, with
rounded ciliate lobes; corolla 0; stamens 7 or 8; filaments villose, longer than the calyx,
much shorter than the calyx in the pistillate flower; ovary villose; style elongated, with
short spreading lobes. Fruit villose, with long scattered pale hairs until nearly grown,
becoming glabrous at maturity, the wings wide-spreading or divergent, 5' |' long; seeds
smooth, light red-brown, about \' long.
A tree, usually 20-25 high, with a trunk a foot in diameter, occasionally 40 high, with
a trunk 18'-20' in diameter, short slender branches forming a rather compact round-topped
head, and slender glabrous branchlets dark green when they first appear, becoming bright
red-brown and lustrous during their first summer, and marked by numerous small oblong
pale lenticels, gradually growing darker in their second year and finally light gray-green.
Winter-buds ovoid, acute, dark brown, glabrous, rather more than yV long, the inner
scales becoming bright crimson and very conspicuous when the tree is in flower. Bark
of young stems and large branches close, light gray or grayish brown, becoming near the
base of old trees dark brown or often nearly black and broken by deep furrows into narrow