This section is from the book "The Standard Cyclopedia Of Horticulture Vol2", by L. H. Bailey. See also: Western Garden Book: More than 8,000 Plants - The Right Plants for Your Climate - Tips from Western Garden Experts.
(Greek, viper; possibly from its poisonous milky juice or from its twining habit). Apocynaceas. Tropical American twining shrubs related to Dipla-denia, and of similar culture.
The genus differs technically from Dipladenia in the 5-lobed disk and the glandular or 5-scaled calyx. Leaves simple, opposite, penninerved: flowers usually showy, purple, red, yellow or white, in sub-cymose clusters; calyx small, 5-lobed, with many glands at the base inside or else 5 scales opposite the lobes; corolla salver-shaped, the throat usually contracted, the limb 5-lobed; stamens included, the filaments very short; stigma with an appendage in the form of a reversed cup or of 5 lobes. - Some 40 species, S. Fla. to Chile.
Leaves 1 1/2-2 in. long, close together, oval or oblong, mucronate, acute or rounded at the base, margins revolute: peduncles axillary, 3-5-flowered, shorter than the leaves; flowers yellow, 2 in. long; corolla-tube much dilated above the insertion of the stamens, bell-shaped, scarcely longer than the lobes; anthers tapering into a long bristle-like awn. Sandy shores, S. Fla., W. Indies. B.M. 1064. P.M. 7:101.
Vahl. Leaves oblong, oval-oblong, or lanceolate-oblong, rounded toward the mucronate top: calyx-segments glandular, devoid of an interior scale, oblong, mucronate-blunt, spreading; corolla-tube funnel-shaped above a cylindrical base; anthers oblong-lanceolate, acuminate, rounded-cordate at the base, hirsute on the back above. Mangrove swamps, S. Fla.
Jacq. Leaves ovate or ovate-roundish, mucronate: flowers greenish white; calyx-segments glandular, devoid of an interior scale; corolla-tube cylindrical, enlarged below the middle, tapering again above; anthers rigid, tapering from a hastate base, glabrous. S. Fla., W. Indies. Wilhelm Miller.