A tree, in the forest occasionally 120° high, with a tall straight trunk rarely 4½° in diameter, slender branches forming a narrow round-topped head, and branchlets light green often tinged with purple and pilose with scattered pale hairs when they first appear, light orange color or reddish brown, covered with a slight bloom during their first winter, and marked by numerous conspicuous pale lenticels and by the elevated oval leaf-scars ¼′ long and displaying a circular row of large fibro-vascular bundle-scars, becoming darker in their second and third years; usually smaller, and in open situations rarely more than 50° high, with a short trunk and a broad head of spreading branches. Winter-buds covered by loosely imbricated ovate chestnut-brown scales keeled on the back, slightly apiculate at apex, those of the inner ranks at maturity foliaceous, obovate, acute, gradually narrowed below to a sessile base, many-nerved with dark veins, pubescent on the lower surface, and sometimes 2½′ long and ¾′ wide. Bark of the trunk ¾′—1′ thick, brown tinged with red, and broken on the surface into thick scales. Wood light, soft, not strong, coarse-grained, light brown, with thin nearly white sapwood of 1 or 2 layers of annual growth; largely used for fence-posts, rails, telegraph and telephone poles, and occasionally for furniture and the interior finish of houses.
Distribution. Borders of streams and ponds, and fertile often inundated bottom-lands; valley of the Vermilion River, Illinois, through southern Illinois and Indiana, western Kentucky and Tennessee, southeastern Missouri and northeastern Arkansas; very abundant and probably of its largest size in southern Illinois and Indiana; naturalized through cultivation in southern Arkansas, western Louisiana, and eastern Texas.
Often planted in the prairie region of the Mississippi basin as a timber-tree, and as an ornament of parks and gardens in the eastern states, and now in many other countries with a temperate climate.
3. ENALLAGMA Bail.
Trees, with scaly bark, and stout slightly angled branchlets. Leaves alternate, short-petiolate, persistent. Flowers solitary, or in few-flowered fascicles on long bibracteolate peduncles from the axils of upper leaves or from the sides of the branches; calyx coriaceous, splitting in anthesis into 2 unequal broad divisions, or sometimes slightly 5-lobed, deciduous; corolla inserted under the hypogynous pulvinate fleshy disk, yellow streaked with purple, or dingy purple, tubular-campanulate, more or less ventricose on the lower side by a transverse fold, abruptly dilated into an oblique 2-lipped obscurely 5-lobed laciniately toothed limb; stamens 4, inserted in 2 ranks on the tube of the corolla, in pairs of different lengths, introrse, included or slightly exserted; filaments filiform; anthers oblong, the cells divergent; staminodium solitary, posterior, often 0; ovary sessile, 1-celled, ovate-conic, gradually narrowed into an elongated simple exserted style; stigma terminal, 2-lobed, the lobes stigmatic on their inner face, or entire; ovules in many ranks on 2 thickened 2-lobed lateral parietal placentas. Fruit baccate, oblong or ovoid; indehiscent, umbonate at apex, many-seeded; pericarp thin and brittle; becoming hard, light brown and separable into 2 layers, the inner membranaceous, filled with the united and thickened fleshy viscid placentas attached at base by a cluster of thick fibro-vascular bundles. Seeds imbedded irregularly in the placental mass, compressed, suborbicular, cordate above and below and deeply grooved on the convex faces; embryo filling the seminal cavity, flattened, thick and fleshy, deeply grooved, becoming black in drying; radicle minute, turned toward the lateral hilum.
Enallagma with three or four species is distributed from southern Florida through the Antilles to southern Mexico and Central America.
1. [Enallagma cucurbitina] Urb. Black Calabash Tree.
Crescentia cucurbitina L.
Leaves crowded near the end of the branches, obovate-oblong or ovate-oblong, contracted into a short broad point or rarely rounded or emarginate at apex, gradually narrowed and cuneate at base, and entire, with cartilaginous slightly revolute margins, coriaceous, dark green and lustrous above, paler and yellow-green below, 6′—8′ long and 1½′—4′ wide, with a broad stout midrib deeply impressed on the upper side, conspicuous primary veins arcuate and united near the margins, and reticulate veinlets; unfolding in the spring, and persistent until their second year; petioles thick, covered with glands, and about ¼′ in length. Flowers appearing in April and May and also in autumn, bad-smelling, on thick drooping pedicels solitary in the axils of upper leaves, 1½′—2′ long, furnished below the middle with 2 minute rigid acute bractlets and enlarged at apex into the thick oblique receptacle; calyx light green and slightly glandular at base, splitting nearly to the bottom into 2 ovate pointed lobes nearly as long as the tube of the corolla; corolla thick and leathery, dull purple or creamy white, and marked by narrow purple bands on the lower side, and 2′ long, with a narrow tube creamy white within and slightly contracted above the base, the transverse fold near its apex, the limb erosely cut on the margins and obscurely 2-lipped, the upper lip slightly divided into 2 reflexed lobes, the lower obscurely 3-lobed; stamens inserted near the middle of the tube of the corolla, those of the anterior pair below the others and above the linear staminodium; ovary obliquely conic; stigma 2-lobed. Fruit ovoid or oblong, 3′—4′ long, 1½′—2′ wide, dark green, minutely rugose-punctulate, and marked with 4 obscure longitudinal ridges corresponding with the margins and midrib of the carpellary leaves, raised on the thickened woody disk and pendent on a stout drooping stalk 1½′—2′ long and much enlarged at apex; shell 1/16′ thick, ultimately hard and brittle, lustrous on the outer surface and lined with a thin membranaceous shining light brown coat marked by the broad placental scars; seeds ⅝′ long and broad and ¼′ thick, with a minute lateral hilum just above the basal sinus; seed-coat of 2 layers, the outer thin, dark reddish brown, rugose, and separable from the thick pale felt-like inner layer; cotyledons with 2 ear-like folds near the base, inclosing the radicle in their lower sinus.