Herbs, annual, erect to decumbent. Roots at proximal nodes. Stems diffusely branched. Leaves: blade narrowly lanceolate to ovate-elliptic, 5--12 ´ 1--4 cm, apex acute to acuminate. Inflorescences: distal cyme usually vestigial, included, sometimes 1-flowered, exserted; spathes solitary, green, paler or whitish basally with contrasting, dark green veins, pedunculate, usually not falcate, 1.5--3(--3.5) ´ 0.8--1.3(--1.8) cm, margins distinct, scabrous, not ciliate, apex acute to acuminate, glabrous to puberulent; peduncles 0.8--3.5(--5) cm. Flowers bisexual (rarely staminate); proximal petal paler or white, very reduced, distal petals blue to bluish purple; staminodes 3; antherodes yellow sometimes with central maroon spot, cruciform. Capsules 2-locular, 2-valved, 4.5--8 mm. Seeds 4, brown, (2--)2.5--4.2 ´ 2.2--3 mm, rugose pitted-reticulate. Flowering summer--fall. Weedy and waste places; edges of fields, woods, and marshes, often in thick herbaceous vegetation; occasionally in woods; introduced; Ont., Que.; Ala., Ark., Conn., Del., D.C., Ga., Ill., Ind., Iowa, Kans., Ky., La., Md., Mass., Mich., Minn., Miss., Mo., Nebr., N.J., N.Y., N.C., Ohio, Okla., Pa., R.I., S.C., S.Dak., Tenn., Tex., Va., W.Va., Wis.; native, Asia. Commelina communis var. ludens (Miquel) C. B. Clarke is distinguished by its darker flowers, antherodes with maroon centers (instead of entirely yellow), distalmost cyme less well developed and usually not producing a flower, and spathes proportionally broader. I have not found it possible to separate this regularly from C. communis var. communis, which also occurs in the flora. A variegated form of C. communis var. ludens, forma aureostriata MacKeever, occurs spontaneously and has been noted from Arkansas, Kentucky, Louisiana, Maryland, North Carolina, Texas, and Virginia.
Fibrous-rooted annual; stems at first erect, later diffuse and rooting from the lower nodes, to 8 dm; lf-blades lance-ovate, the larger 5-12 נ1.5-4 cm; sheaths 1-2 cm; spathe (folded) broadly semicordate, 1.5-3 cm, half as wide, acute or short-acuminate, glabrous or minutely hairy, basally with dark green veins on a paler background, its margins free, its stalk 1-7 cm; blade of upper pet 8-15 mm; lower median pet white or nearly so; anthers 6 (3 sterile); ovary 3-locular; fr 2-locular and 4-seeded, the upper locule of the ovary abortive; 2n=36-90. Moist or shaded ground, often a garden-weed; native of e. Asia, intr. from N.H. to Ga., w. to N.D. and Tex. Several forms, often locally constant, differing in details of pubescence, size and intensity of color of pet, and color of sterile stamens.
Gleason, Henry A. & Cronquist, Arthur J. 1991. Manual of vascular plants of northeastern United States and adjacent Canada. lxxv + 910 pp.