Madagascar periwinkle

Vinca rosea Linnaeus, Syst. Nat. ed. 10, 2: 944. 1759; Lochnera rosea (Linnaeus) Reichenbach ex Spach

Subshrubs or herbs perennial, 3–10(–20) dm. Leaves: petiole (1–)3–11 mm, sparsely pubes­cent or glabrous; blade elliptic to obovate, oblong, or rarely lanceolate, (1–)2.5–9 × (0.6–)0.8–4 cm, membranous, base cuneate to attenuate, apex rounded to acute or obtuse, mucronulate, surfaces sparsely pubescent or glabrous. Peduncles 1–4 mm, sparsely pubescent or glabrous, occasionally absent. Pedicels 0–1 mm, sparsely pubescent or glabrous. Flowers: calyx lobes narrowly lanceolate, 2–6 mm, sparsely pubescent or glabrous; corolla eglandular-pubescent abaxially and adaxially, tube (15–)20–30 × 1–1.5 mm, throat 4–5 × 2–3 mm, lobes spreading, broadly obovate, often mucronulate, (5–)10–28 × 10–25 mm. Follicles (12–)20–50 × 1.5–2 mm. Seeds 1–3 × 0.5–1.5 mm. 2n = 16.

Flowering spring–fall; fruiting summer–fall. Dis­turbed areas, old homesites; 0–300 m; introduced; Ala., Calif., Fla., Ga., Kans., La., Miss., N.C., S.C., Tenn., Tex.; Indian Ocean Islands (Madagascar); widely intro­duced in warmer regions of the world.

Catharanthus roseus is of great pharmaceutical interest for its ability to synthesize a large number (ca. 130) of monoterpenoid indole alkaloids, the best known of which are vinblastine and vincristine (Q. Pan et al. 2016). When purified, both compounds have been shown to be useful for treating certain cancers, especially Hodgkin’s disease, non-Hodgkin’s lymphomas, and acute leukemia (R. Van der Heijden et al. 2004), and act by disrupting microtubules, causing dissolution of the mitotic spindle and metaphase arrest in dividing cells.