A tree, rarely 30°—40° high, with a short crooked and contorted trunk sometimes 18′—20′ in diameter, stout forked divergent branches forming a round-topped compact head, and slender branchlets light green tinged with red and covered with soft white glandular-viscid hairs when they first appear, soon becoming glabrous, and in their first winter green tinged with red and very lustrous, turning bright red-brown during their second year and paler the following season, the bark then separating into large thin papery scales exposing the cinnamon-red inner bark, and marked with large deeply impressed leaf-scars showing near the centre a crowded cluster of fibro-vascular bundle-scars; more often a dense broad shrub 6°—10° high, with numerous crooked stems. Winter-buds formed before midsummer in the axils of the leaves just below those producing the inflorescence-buds, their inner scales accrescent, and at maturity often 1′ long and ½′ wide, ovate, acute, light green, covered with glandular white hairs, and in falling marking the base of the shoots with conspicuous broad scars. Bark of the trunk hardly more than 1/16′ thick, dark brown tinged with red, and divided by longitudinal furrows into narrow ridges separating into long narrow scales. Wood heavy, hard, strong, rather brittle, close-grained, brown tinged with red, with slightly lighter colored sapwood; used for the handles of tools, in turnery, and for fuel.
Distribution. New Brunswick to the northern shores of Lake Erie and southward in the Atlantic coast region to Virginia and to southern Ohio, Martin and Crawford Counties, Indiana and central Tennessee, along the Appalachian Mountains and their foothills to Georgia, and from western Florida through Alabama to eastern and southern Mississippi and the valley of the Bogue Lusa River, Washington Parish, Louisiana; often growing in low moist ground near the margins of swamps or on dry slopes under the shade of deciduous-leaved trees, or on rich rocky hillsides; most abundant and often forming dense impenetrable thickets on the southern Appalachian Mountains up to altitudes of 3000°—4000°; usually shrubby, and only arborescent in a few secluded valleys between the Blue Ridge and the Alleghany Mountains of North and South Carolina; abundant and of large size along small streams in Liberty County, western Florida. The var. myrtifolia K. Koch with small lance-oblong leaves, and small compact clusters of small flowers, a compact dwarf shrub, and an old inhabitant of European gardens, is occasionally wild in Massachusetts; in an abnormal form (f. polypetala Rehd.) found in western Massachusetts the corolla is divided into 5 narrow petals.
Often cultivated as an ornament of parks and gardens in the eastern states, and in Europe.
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.