1. Murdannia keisak (Hasskarl) Handel-Mazzetti, Symb. Sin. 7: 1243. 1936.
Aneilema keisak Hasskarl, Commelin. Ind., 32. 1870
Herbs, annual, with long-trailing, decumbent shoots. Leaves: blade linear-oblong to linear-lanceolate, 1.5--7 ´ 0.2--1 cm, glabrous. Inflorescences terminal and in distal leaf axils; cymes 1-several, 1-flowered, solitary or fascicled. Flowers bisexual, radially symmetric, 1 cm wide; sepals 5--6 mm; petals purplish lilac or purple to pink or white, 5--8 mm; stamens 3; filaments bearded; staminodes 3. Capsules (4--)5--9 mm. Seeds 2--6 per locule, 1.6--3 mm, faintly ribbed.
Flowering fall. Roadside ditches and swales, margins of lakes, creeks, rivers, swamps, bogs, swamp forest, and other aquatic habitats, often growing in water; introduced; Ark., Fla., Ga., Ky., La., Md., Miss., N.C., Oreg., S.C., Tenn., Va., Wash.; Europe; native, Asia.
I agree with C. P. Dunn and R. R. Sharitz (1990) that this species is still expanding its range since its introduction early this century.
SELECTED REFERENCE
Dunn, C. P., and R. R. Sharitz. 1990. The history of Murdannia keisak (Commelinaceae) in the southeastern United States. Castanea 55: 122--129.