1. Gelsemium Jussieu, Gen. Pl. 150. 1789.
[Italian gelsemino, from Persian-Arabic yasamin, jasmine, probably alluding to similarity of flowers]
Stems: internodes glabrous, puberulent, or retrorsely scabridulous, nodes glabrous to antrorsely short-pubescent. Leaves: stipular colleters linear, 1–4 on each side of petiole base. Inflorescences: flowers solitary or in reduced, simple cymes, pedicellate; bracteoles lanceolate, ovate, or deltate, proximal usually with single linear colleter at base on each side. Flowers fragrant or not; sepals lanceolate, ovate, or oblong, apex acuminate, obtuse, or rounded; corolla yellow to orange, lobe apex obtuse, rounded, or emarginate [acuminate]; stamens inserted at base to middle of tube; filaments glabrous; anthers connivent or separate, sagittate; styles glabrous. Capsules elliptic to oblong, dehiscence septicidal into 4 segments. Seeds ovate [elliptic to reniform], wings absent or unilateral [circumferential]. x = 8.
Species 3 (2 in the flora): e United States, Mexico, Central America, e Asia.
SELECTED REFERENCES Ornduff, R. 1970e. The systematics and breeding system of Gelsemium (Loganiaceae). J. Arnold Arbor. 51: 1–17. Rogers, G. K. 1986. Genera of Loganiaceae in the southeastern United States. J. Arnold Arbor. 67: 143–185.