A tree or shrub, with pale slightly fissured bark, scaly buds, stout terete pithy branchlets marked by pale conspicuous nearly circular lenticels and by elevated crescent-shaped angled or obscurely 3-lobed leaf-scars, very light soft wood, and thick fleshy stoloniferous yellow roots. Leaves involute in the bud, lanceolate to elliptic-lanceolate, acuminate or acute and short-pointed at apex, gradually narrowed at base, entire, with slightly revolute undulate margins, penniveined with remote primary veins arcuate and united near the margins, and conspicuous reticulate veinlets, petiolate, at first coated on the lower surface and on the petioles with thick pale tomentum and puberulous on the upper surface, thick and firm at maturity, bright green and lustrous above, pale and villose-pubescent below, deciduous. Flowers in unisexual aments, with ovate acute concave tomentose scales, the male and female on different plants, opening in early spring from buds formed the previous autumn and covered with acute chestnut-brown hairy scales; the staminate clustered near the end of the branches, their scales bearing on the thickened stipe a ring of 3—12 stamens, with slender incurved filaments and oblong light yellow introrse 2-celled anthers opening longitudinally; perianth 0; pistillate aments scattered, shorter and more slender than the staminate, their scales bearing in their axils a short-stalked pistil surrounded by a rudimentary perianth of small gland-fringed scales, the 2 larger lateral, the others next the axis of the inflorescence; ovary superior, pubescent, 1-celled, with an elongated flattened style inserted obliquely, curving inward above the middle in anthesis, grooved and stigmatic on the inner face; ovule solitary, attached laterally, ascending, semianatropous; micropyle directed upward. Fruit an oblong compressed dry drupe thick and rounded on the ventral, narrowed on the dorsal edge, rounded at base, thin and pointed at apex, chestnut-brown, rugose, with a thick dry exocarp closely investing the thin-walled light brown crustaceous rugose nutlet. Seed flattened, rounded at the ends, light brown, marked on the thick edge with the oblong nearly black hilum; embryo erect, surrounded by thin fleshy albumen; cotyledons oblong, flattened; radicle superior, conical, short, and fleshy. The family consists of a single genus, _Leitneria_ Chapm., with one species of the southern United States, named for a German naturalist killed in Florida during the Seminole War. 1. Leitneria floridana Chapm. Cork Wood. [Illustration: Fig. 162] Leaves 4′—6′ long, 1½′—2½′ wide, with petioles 1′—2′ in length. Flowers opening at the end of February or early in March; staminate aments 1′—1¼′ long, ¼′ thick, and twice as long as the pistillate. Fruit solitary or in clusters of 2—4, ripening when the leaves are about half grown, ¾′ long, ¼′ wide.