A tree, 20°—30° high, with a trunk usually more or less reclining, often hollow, and sometimes a foot in diameter, slender upright branches forming a narrow head, and branchlets glabrous or covered with dense tomentum when they first appear, light chestnut-brown during their first season, later becoming darker and tinged with red, or sometimes ashy gray; or often a straggling shrub. Bark of the trunk ⅛′—¼′ thick, dark brown, and divided into broad branching ridges broken on the surface into small thick plate-like scales. Wood soft, not strong, close-grained, brown streaked with yellow, with thin light-colored sapwood of 2 or 3 layers of annual growth.
Distribution. Banks of streams, and depressions in the desert, usually in dry gravelly porous soil; valley of the lower Rio Grande, and through western Texas, southern New Mexico, Arizona, southern Utah and Nevada to San Jacinto Valley, San Diego County, California; in northern Mexico and Lower California (Calamujuit).
Occasionally cultivated as an ornamental plant in the southern states, and in Mexico.
2. CATALPA Scop.
Trees, with stout terete branchlets, without a terminal bud, minute globose axillary buds nearly immersed in the bark and covered by numerous scales, the inner accrescent, thick pith, thin scaly bark, soft light-colored wood very durable in contact with the soil, and fibrous roots. Leaves opposite or in verticels of 3, involute in the bud, entire or lobed, oblong-ovate, often cordate, long-petiolate, deciduous. Flowers on slender bracteolate pedicels, in terminal compound trichotomously branched panicles or corymbs, with linear-lanceolate deciduous bracts and bractlets; calyx membranaceous, subglobose, closed and apiculate in the bud, in anthesis splitting nearly to the base into 2 broad-ovate entire pointed apiculate lobes; corolla thin, variously marked and spotted on the inner surface, inserted on the nearly obsolete disk, the tube broad, campanulate, occasionally furnished on the upper side near the base with an external lobed appendage, and oblique and enlarged above into a broad limb, with spreading lips undulate on the margin, the posterior 2-parted, the anterior deeply 3-lobed; stamens and staminodia inserted near the base of the corolla; stamens 2, anterior, included or slightly exserted; filaments flattened, arcuate; anthers oblong, carried to the rear of the corolla and face to face on either side of the stigma by a half turn of the filaments near their base, the cells divergent in anthesis; staminodia 3, free, filiform, minute or rudimentary; ovary 2-celled, sessile on the hypogynous nearly obsolete disk, abruptly contracted into an elongated filiform style divided at apex into 2 stigmatic lobes exserted above the anthers; ovules inserted in many series on a central placenta. Fruit an elongated subterete capsule tapering from the middle to the ends, persistent on the branches during the winter, ultimately splitting into 2 valves. Seeds numerous, compressed, oblong, inserted in 2—4 ranks near the margin of the flat or more or less thickened woody septum free from the walls of the capsule; seed-coat thin, light brown or silvery gray, longitudinally veined, produced into broad lateral wings notched at base of the seed and divided at their narrowed or rounded ends into tufts of long coarse white hairs; cotyledons plane, broader than long, slightly 2-lobed, rounded laterally; radicle short, erect, turned toward the oblong conspicuous basal hilum.
Catalpa with seven species is confined to the eastern United States, the West Indies, and eastern China, two of the species being North American. Catalpa contains a bitter principle and is a tonic and diuretic.
The generic name is that by which one of the North American species was known among the Cherokee Indians.
CONSPECTUS OF THE NORTH AMERICAN SPECIES.
Flowers in many-flowered crowded panicles; calyx glabrous; corolla thickly-spotted on the inner surface; fruit slender, thin-walled; leaves short-acuminate.1. [C. bignonioides] (C). Flowers in few-flowered open panicles; calyx often sparingly villose or pubescent; corolla inconspicuously spotted; fruit stout, thick-walled; leaves caudate-acuminate.2. [C. speciosa] (A, C).