4. OXYDENDRUM DC.
A tree, with thick deeply furrowed bark, slender terete glabrous light red or brown branchlets, without a terminal bud, marked by elevated nearly triangular leaf-scars displaying a lunate row of crowded fibro-vascular bundle-scars, and numerous elevated oblong dark lenticels, acid foliage, and fibrous roots. Winter-buds axillary, minute, partly immersed in the bark, obtuse, covered with opposite broad-ovate dark red scales rounded at apex, those of the inner ranks accrescent. Leaves alternate, revolute in the bud, oblong or lanceolate, acute, gradually contracted at base into a long slender petiole, serrate with minute incurved callous teeth, penniveined, with a conspicuous bright yellow midrib and reticulate veinlets, thin and firm, dark green and lustrous on the upper surface, pale and glaucous on the lower surface, glabrous or at first slightly puberulous, deciduous. Flowers on erect clavate pedicels coated with hoary pubescence and bibracteolate above the middle, with linear acute caducous bractlets, in puberulous panicles of secund racemes appearing in summer and terminal on axillary leading shoots of the year, the lower racemes in the axils of upper leaves; calyx free, divided nearly to the base, the divisions valvate in the bud, ovate-lanceolate, acute, pubescent or puberulous on the outer surface, persistent under the fruit; corolla hypogynous, cylindric to ovate-cylindric, white, puberulous, 5-lobed, the lobes minute, ovate, acute, reflexed; stamens 10, included; filaments subulate, broad, pilose, inserted on the very base of the corolla; anthers linear-oblong, narrower than the filaments, the cells opening from the apex to the middle; disk thin, obscurely 10-lobed; ovary broad-ovoid, pubescent, 5-celled; style columnar, thick, exserted, crowned with a simple stigma; ovules attached to an axile placenta rising from the base of the cell, ascending, amphitropous. Fruit a 5-celled ovoid-pyramidal many-seeded capsule crowned with the remnants of the persistent style, 5-lobed, puberulous, loculicidally 5-valved, the valves woody, separating from the central persistent placentiferous axis, many-seeded. Seeds ascending, elongated; seed-coat membranaceous, loose, reticulated, produced at the ends into long slender points; embryo minute, axile in fleshy albumen, cylindric; radicle terete, next the hilum.
The genus consists of a single species.
The generic name is from ὀξύς and δένδρον, in allusion to the acid foliage.
1. [Oxydendrum arboreum] DC. Sorrel-tree. Sour Wood.
Leaves when they unfold bronze-green, very lustrous and glabrous with the exception of a slight pubescence on the upper side of the midrib and a few scattered hairs on the under side of the midrib and on the petioles, and at maturity 5′—7′ long and 1½′—2½′ wide; turning bright scarlet in the autumn; petioles ⅔′ in length. Flowers opening late in July or early in August, ⅓′ long, in panicles 7′—8′ in length. Fruit ⅓′—½′ long, hanging in drooping clusters sometimes a foot in length, ripening in September, the empty capsules often persistent on the branches until late in the autumn; seeds about ⅛′ long, pale brown.
A tree, occasionally 50°—60° high, with a tall straight trunk 12′—20′ in diameter, slender spreading branches forming a narrow oblong round-topped head, and glabrous branchlets yellow-green and marked by orange-colored lenticels when they first appear, becoming in their first winter orange-colored to reddish brown. Winter-buds about 1/16′ long, their inner scales at maturity 1′ in length, ⅛′ wide, spatulate, acute at apex, and slightly puberulous on the inner surface and on the margins. Bark of the trunk ⅔′—1′ thick, gray tinged with red and divided by longitudinal furrows into broad rounded ridges covered with small thick appressed scales. Wood heavy, hard, very close-grained, brown tinged with red, with lighter colored sapwood of 80—90 layers of annual growth; sometimes used locally for the handles of tools and the bearings of machinery. The leaves have a pleasant acidulous taste, and are reputed to be tonic, refrigerant, and diuretic, and are occasionally used in domestic practice in the treatment of fevers.
Distribution. Well-drained gravelly soil on ridges rising above the banks of streams; coast of Virginia (Norfolk County) to that of North Carolina (near Newbern, Craven County), southwestern Pennsylvania to southern Ohio and Indiana (Perry County), and to western Kentucky and Tennessee, along the Appalachian Mountains and their foothills, and southward to western Florida, the shores of Mobile Bay, the coast region of Mississippi, and West Feliciana Parish, Louisiana; up to altitudes of 3500° on the southern mountains; of its largest size on the western slopes of the Big Smoky Mountains, Tennessee.
Often cultivated as an ornamental plant in the eastern states and hardy as far north as eastern Massachusetts, and occasionally in western and central Europe.