Distribution. Limestone hills and river banks; rare and local; eastern (near Pikeville, Pike County) and southern Kentucky (Bowling Green, Warren County); banks of the Cumberland River, near Clarksville and Nashville, Tennessee; northeastern Georgia (cliffs of the Coosa River, near Rome, Floyd County); northern Alabama (Madison, Jefferson and Tuscaloosa Counties); valley of the Arkansas River (near Van Buren, Crawford County, G. M. Brown) and northwestern Arkansas (Sulphur Springs, Benton County, and Boston Mountains near Jasper, Newton County, E. J. Palmer); eastern Oklahoma (near Muskogee, Muskogee County, B. H. Slavin); southwestern (Grand Tower, Jackson County, H. A. Gleason) and southern Illinois (Richland County, R. Ridgway).
Occasionally planted as a shade-tree in the streets of cities in northern Georgia and northern Alabama; hardy in Eastern Massachusetts.
2. PLANERA Gmel.
A tree, with scaly puberulous branchlets roughened by scattered pale lenticels, and at the end of their first season by small nearly orbicular leaf-scars marked by a row of fibro-vascular bundle-scars, minute subglobose winter-buds covered by numerous thin closely imbricated chestnut-brown scales, the outer more or less scarious on the margins, the inner accrescent, becoming at maturity ovate-oblong, scarious, bright red, ⅓′—½′ long, marking in falling the base of the branchlet with pale ring-like scars. Leaves alternate, 2-ranked, ovate-oblong, acute or rounded at the narrowed apex, unequally cuneate or rounded at base, coarsely crenately serrate with unequal gland-tipped teeth, with numerous straight conspicuous veins forked near the margin and connected by cross reticulate veinlets more conspicuous below than above, when they unfold puberulous on the lower and pilose on the upper surface, at maturity thick or subcoriaceous and scabrate; petiolate with slender terete puberulous petioles; stipules lateral, free, ovate, scarious, bright red. Flowers polygamo-monœcious, the staminate fascicled in the axils of the outer scales of leaf-bearing buds, short-pedicellate, the pistillate or perfect on elongated puberulous pedicels in the axils of the leaves of the year in 1—3-flowered fascicles; pedicels without bracts; calyx campanulate, divided nearly to the base into 4 or 5 lobes rounded at apex, greenish yellow often tinged with red; stamens inserted under the ovary in the pistillate flower, sometimes few or 0; filaments filiform, erect, exserted; anthers broadly ovate, emarginate, cordate; ovary ovoid, stipitate, glandular-tuberculate, narrowed into a short style divided into 2 elongated reflexed stigmas papillo-stigmatic on the inner face, 0 in the staminate flower; ovule anatropous; micropyle extrorse, superior. Fruit an oblong oblique drupe, narrowed below into a short stipe, inclosed at the base by the withered calyx, crowned by the remnants of the style, its pericarp crustaceous, prominently ribbed on the anterior and posterior faces, irregularly tuberculate with elongated projections, and light chestnut-brown; seed ovoid, oblique, pointed at apex, rounded below, without albumen; testa thin, lustrous, dark brown or nearly black, of two coats; raphe inconspicuous; embryo erect; cotyledons thick, unequal, bright orange color, the apex of the larger hooded and slightly infolding the smaller, much longer than the minute radicle turned toward the linear pale hilum.
The genus is represented by a single species.
The generic name is in memory of Johann Jacob Planer, a German botanist and physician of the eighteenth century.
1. [Planera aquatica] Gmel. Water Elm.
Leaves 2′—2½′ long, ¾′—1′ wide, on petioles varying from ⅛′—¼′ in length, dark dull green on the upper surface, paler on the lower surface, with a yellow midrib and veins. Flowers appearing with the leaves. Fruit ripening in April, ⅓′ long.
A tree, 30°—40° high, with a short trunk rarely exceeding 20′ in diameter, rather slender spreading branches forming a low broad head, and branchlets brown tinged with red when they first appear, dark red in their first winter, and ultimately reddish brown or ashy gray. Bark about ¼′ thick, light brown or gray, separating into large scales disclosing in falling the red-brown inner bark. Wood light, soft, not strong, close-grained, light brown, with thick nearly white sapwood of 20—30 layers of annual growth.