Herbs, annual, diffusely spreading. Roots at nodes. Stems decumbent to scandent. Leaves: blade lanceolate to lanceolate-elliptic or lanceolate-oblong, 2.5--10.5 ´ 0.7--2.4 cm, margins scabrous, apex acute to acuminate, glabrous. Inflorescences: distal cyme vestigial, included (rarely 1-flowered and exserted); spathes solitary, bright green, paler basally, without contrasting veins, pedunculate, not at all to slightly falcate, 1.2--3(--3.7) ´ 0.5--1 cm, margins distinct, usually ciliate, apex acuminate, glabrous or very sparsely pilose; peduncles 0.6--2.3 cm. Flowers bisexual; petals all blue, proximal petal white medially, smaller; medial stamen with white connective; staminodes 3; antherodes yellow, often with central maroon spot, cruciform. Capsules 3-locular, 2-valved, (5--)6--8 mm. Seeds 5, dark brown, 2.4--4.3(--4.6) ´ (1.6--)2--2.3 mm, smooth to faintly alveolate, mealy. 2n = ca. 86. Flowering summer--fall (rarely winter). Fields, roadsides, railroad rights-of-way, yards, waste places, especially in moist situations, weed in crops, especially rice, sugar cane and corn, and rarely in forests; introduced; Ala., Ark., Fla., Ga., La., Md., Miss., Mo., N.C., S.C., Tex.; native, India.
Spathes not at all or only slightly falcate; upper cyme generally vestigial (rarely well developed and 1-fld); fr (5)6-8 mm; seeds of the lower locules 2.4-4.3(-4.6) mm, smooth or faintly alveolate; otherwise much like no. 2 [Commelina diffusa Burm.f.]. Native of India, long intr. and weedy in se. U.S., n. to Md.
Gleason, Henry A. & Cronquist, Arthur J. 1991. Manual of vascular plants of northeastern United States and adjacent Canada. lxxv + 910 pp.
