1. PLATANUS L. Plane-tree.
Characters of the family.
A genus of four or five species of eastern and western North America, Mexico, Central America, and of southwestern Asia, all resembling each other except in the form of the lobes of the leaves and the amount of pubescence on their lower surface, in the pointed or obtuse apex of the akene, and in the number of heads of pistillate flowers on their peduncle.
Of the exotic species, the Old World Platanus acerifolia Willd., of doubtful origin, and often considered a hybrid between P. orientalis L. and the Plane-tree of the eastern United States, is now a common street tree in the cities of all the countries of temperate Europe, and is largely used as a street and shade tree in the eastern states and in California.
Platanus is the classical name of the Plane-tree.
CONSPECTUS OF THE NORTH AMERICAN SPECIES.
Heads of fruit usually solitary; leaves broadly ovate, slightly 3—5-lobed, the lobes broad, mostly serrulate, or entire, truncate or rarely cuneate at base.1. [P. occidentalis] (A, C). Heads of fruit racemose. Leaves 3—5-lobed to below the middle, the lobes entire, remotely and obscurely dentate, or rarely sinuate-toothed, truncate or slightly cordate or cuneate at base.2. [P. racemosa] (G). Leaves deeply 5—7-lobed, the lobes elongated, slender, entire, or rarely remotely dentate, deeply cordate or rarely cuneate or truncate at base.3. [P. Wrightii] (H).
1. [Platanus occidentalis] L. Sycamore. Buttonwood.
Leaves broadly ovate, more or less 3—5-lobed by broad shallow sinuses rounded at the bottom, the lobes broad, acuminate, sinuate-toothed with long straight or curved remote acuminate teeth, or entire with undulate margins, truncate or slightly cordate, or long-cuneate and decurrent on the petiole at base (var. attenuata Sarg.), thin and firm, bright green on the upper surface, paler on the lower, glabrous at maturity with the exception of a slight pubescence on the under side of the thin midrib and stout yellow veins, 4′—7′ long and broad, or twice as large on vigorous shoots and then frequently furnished with dentate basal lobes; petioles stout, terete or slightly angled, becoming puberulous 3′—5′ in length; stipules 1′—1½′ long, entire or sinuate-toothed. Flowers: peduncles coated with pale tomentum, bearing 1 and sometimes 2 heads of flowers. Fruit: heads 1′ in diameter, on slender glabrous stems 3′—6′ in length; akene about ⅔′ long and truncate or obtusely rounded at apex.
A tree, occasionally 140°—170° high, with a trunk sometimes 10°—11° in diameter above its abruptly enlarged base, often divided near the ground into several large secondary trunks, or rising 70°—80°, with a straight column-like shaft free of branches and with little diminution of diameter, massive spreading limbs forming a broad open irregular head sometimes 100° in diameter, their extremities usually erect or more or less pendulous, and slender branchlets coated at first like the leaves, petioles, and stipules with thick pale deciduous tomentum, during their first summer dark green and glabrous, marked by minute oblong pale lenticels, becoming dark orange-brown and rather lustrous during their first winter and light gray in their second year. Winter-buds ¼′—⅜′ long. Bark of young trunks and large branches rarely more than ½′ thick, dark reddish brown, broken into small oblong thick appressed plate-like scales, smooth, light gray, and separating higher on the tree into large thin scales, in falling exposing large irregular surfaces of the pale yellow, whitish, or greenish inner bark, becoming at the base of large trunks 2′—3′ thick, dark brown, and divided by deep furrows into broad rounded ridges covered by small thin appressed scales. Wood the favorite material for tobacco boxes, ox-yokes, and butcher’s blocks, and now largely used for furniture and the interior finish of houses.
Distribution. Borders of streams and lakes on rich bottom-lands; southeastern Maine to northern Vermont and through southern Ontario and Michigan to central and southern Iowa, southeastern Nebraska, eastern Kansas, and eastern Oklahoma to the valley of the Arkansas River (Clay County), and southward to western Florida (Gladsden County) central Alabama and Mississippi, and the valley of the Rio Grande (Zavalla County) western Texas; common but most abundant and of its largest size on the bottom lands of streams in the basin of the lower Ohio and Mississippi rivers; less abundant and of smaller size in the coast region of the Carolinas and in western Texas; ascending the Appalachian Mountains up to altitudes of 2500°. The most massive if not the tallest deciduous-leaved tree of eastern North America.
Sometimes planted as a street tree, especially in the cities of eastern Texas; passing into
1. [Platanus occidentalis] var. glabrata Sarg.
Platanus glabrata Fern.
Leaves usually broader than long, truncate, broad-cuneate or rarely cordate at base, 3-lobed by sinuses acute or rounded in the bottom, the lobes long-acuminate, entire, the lateral lobes often furnished near the base with one or rarely with two small acuminate incurved secondary lobes occasionally found also on the terminal lobe, tomentose below and pubescent above when the flowers open the end of March in Texas, later becoming glabrous except on the under side of the midrib and veins, usually about 2¾′—5½′ long and 3′—3½′ wide; petioles pubescent, becoming glabrous. Peduncles bearing one or rarely two heads. Flowers and Fruit like those of the species.
Distribution. Western Texas, common; valley of the Colorado River, near Austin, Travis County, to that of the Devil’s River, Valverde County; in Coahuila and Nuovo Leon; rarely northward with widely scattered individuals; the prevailing form on the Edwards Plateau and in the counties adjacent to the Rio Grande.
2. [Platanus racemosa] Nutt. Sycamore.
Leaves 3—5-lobed to below the middle by broad sinuses acute or rounded in the bottom, the lobes acute or acuminate, entire, dentate with remote callous tipped teeth, or occasionally coarsely sinuate-toothed, usually cordate or sometimes truncate, or cuneate and decurrent on the petiole at base, thick and firm, light green above, paler and more or less thickly coated below with pale pubescence most abundant along the midrib and primary veins, 6′—10′ long and broad; petioles stout, pubescent, 1′—3′ in length; stipules 1′—1½′ long, entire or dentate, often persistent until spring. Flowers: peduncles hoary-pubescent, bearing usually 4 or 5 heads of staminate flowers and 2—7 heads of pistillate flowers, a head of the staminate flowers occasionally appearing on the pistillate peduncle above the heads of fertile flowers. Fruit: heads ¾′ in diameter, on slender zigzag glabrous or pubescent stems 6′—9′ in length; akene acute or rounded at apex, ⅓′ long, tomentose while young, becoming glabrous.
A tree, 40°—90° high, with a trunk sometimes 9° in diameter above the broad tapering base, erect and free of branches for half its height, more often divided near the ground into secondary stems erect, inclining, or prostrate for 20°—30° at their base, thick heavy more or less contorted spreading branches forming an open irregular round-topped head, and branchlets coated at first with thick pale deciduous tomentum, light reddish brown, and marked by numerous small lenticels in their first winter, becoming gradually darker in their second and third years; usually smaller, with a trunk 2°—4° in diameter. Winter-buds nearly ½′ long. Bark at the base of old trunks 3′—4′ thick, dark brown, deeply furrowed, with broad rounded ridges separating on the surface into thin scales; thinner, smooth, and pale, or almost white higher on the trunk and on the branches.
Distribution. Banks of the streams of western California; valley of the upper Sacramento River (Tehama County) southward through the interior valleys, along the western foothills of the Sierra Nevada and on the southern coast ranges; and on Mount San Pedro Màrtir in Lower California; exceedingly common in all the valleys of the California coast ranges from Monterey to the southern borders of the state, and ascending the southern slopes of the San Bernardino Mountains to altitudes of 3000°—4000°.
3. [Platanus Wrightii] S. Wats. Sycamore.
Leaves divided by narrow sinuses to below the middle and sometimes nearly to the center into 3—7 but usually into 3—5 elongated acute lobes entire, or dentate with callous-tipped teeth, or occasionally furnished with 1 or 2 lateral lobes, sometimes deeply cordate by the downward projection of the lower lobes, or often truncate or cuneate at base, thin and firm in texture, light green and glabrous above, covered below with pale pubescence, 6′—8′ long and broad, with a slender midrib, and primary veins connected by conspicuous reticulate veinlets; petioles stout, glabrous or puberulous, 1½′—3′ in length. Flowers: peduncles hoary-tomentose, bearing 1—4 heads of flowers. Fruit: heads on slender glabrous stems 6′—8′ long, about ¾′ in diameter; akenes glabrous, ¼′ long, truncate at apex.
A tree, often 60°—80° high, with a straight trunk 4°—5° in diameter, gradually tapering and free of branches for 20°—30°, or with a trunk divided at the ground into 2 or 3 large stems usually more or less reclining and often nearly prostrate for 15°—20°, thick contorted branches, the lowest growing almost at right angles to the trunk and 50°—60° long, the upper usually erect at first, finally spreading into a broad open handsome head, and slender branchlets coated when they first appear with thick pale tomentum, becoming glabrous or slightly puberulous during their first winter, marked by minute scattered lenticels, and light brown tinged with red or ashy gray, and gradually darker in their second or third year. Winter-buds hardly more than ⅛′ long. Bark at the base of the trunk dark, 3′—4′ thick, deeply and irregularly divided into broad ridges, and covered on the surface with small appressed scales, thinner and separating into large scales 10°—15° above the ground, and gradually passing into the smooth much thinner creamy white bark faintly tinged with green of the upper branches.
Distribution. Banks of streams in the mountain cañons of southwestern New Mexico and southern Arizona; in northern Arizona in Oak Creek Cañon near Flagstaff (P. Lowell); and in Sonora; the largest and one of the most abundant of the deciduous-leaved trees on all the mountain ranges of southern Arizona, extending from the mouth of cañons up to altitudes of 5000°—6000° above the sea.