紫背万年青 zi bei wan nian qing

Rhoeo discolor (L’Héritier) Hance; R. spathacea (Swartz) Stearn; Tradescantia discolor L’Héritier.

Herbs perennial. Stems erect, often forming colonies, simple, glabrous. Leaves alternate, sometimes seemingly spirally arranged, sessile; leaf sheath sometimes pilose at mouth; leaf blade dark green adaxially, purple abaxially, oblong-lanceolate, 20--40 × 3--6 cm, glabrous, somewhat fleshy, base narrowed and semiclasping, apex acuminate. Flowers in axillary, pedunculate, simple or forked, many-flowered umbels subtended by 2 large, conduplicate, ovate bracts to 3 cm. Petals white, ovate, 5--8 mm, apex abruptly acute. Seeds rugose.

Naturalized. Hong Kong [native to Caribbean region and Central America].

Widely cultivated as an ornamental in S China. The flower is used medicinally for the treatment of dysentery, enterorrhagia, and hemoptysis.