- Scientific Name: Tradescantia spathacea Sw.
- Ref: Prodr. Veg. Ind. Occ.:57. 1788
- Synonyms: Ephemerum bicolor Moench; Rhoeo discolor (L’Hér.) Hance; R. spathacea (Sw.) Stearn; Tradescantia discolor L’Hér.; T. versicolor Salisb.
- English Common Name: Moses-in-the-cradle, oyster plant, boat lily
- Chinese Common Name: 紫背万年青 zǐbèi wànnián∙qīng, 蚌花 [粤]pong5 faa1
- Japanese Common Name: ムラサキオモト [紫万年青] murasakiomoto
- Family: Commelinaceae
- Genus: Tradescantia
- Distribution: Naturalized. Hong Kong [native to Caribbean region and Central America].
- Photo: 06/21/2009, South China Botanical Garden, Guangdong
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. (Flora of China)