796 TREES OF NORTH AMERICA 



dwarf shrub, and an old inhabitant of European gardens, is occasionally wild in Massa- 

 chusetts; 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 display- 

 ing a lunate row of crowded fibre-vascular bundle-scars, and numerous elevated oblong 

 dark lenticels, acid foliage, and fibrous roots. Winter-buds axillary, minute, partly im- 

 mersed 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. Flow- 

 ers 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 ra- 

 cemes 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 sur- 

 face, persistent under the fruit; corolla hypogynous, cylindric to ovate-cylindric, white, 

 puberulous, 5-lobed, the lobes minute, ovate, acute, re flexed; stamens 10, included; fila- 

 ments 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 placentif- 

 erous 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 6fo and Stvdpov, 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 1|'-2|' wide; turn- 

 ing bright scarlet in the autumn; petioles f in length. Flowers opening late in July or 

 early in August, ' long, in panicles 7'-8' in length. Fruit |'-|' long, hanging in drooping 

 clusters sometimes a foot in length, ripening in September, the empty capsules often per- 

 sistent on the branches until late in the autumn; seeds about f' 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. Whiter-buds about T %' long, their inner 

 scales at maturity 1' in length, %' wide, spatulate, acute at apex, and slightly puberulous on 

 the inner surface and on the margins. Bark of the trunk f '-!' 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 



