Commelina undulata R. Br.

Commelina undulata is common in tropical Oceania, but scattered in Asia. It varies widely, with plants erect or diffuse, glabrous or hairy, and capsule (1 or)2- or 3-valved. The species is characterized by having apically falcate-acuminate involucral bracts only partly connate at the proximal margins, arising opposite the fascicled smaller leaves, and therefore resembling compound heads.

Herbs perennial. Stems erect or ascending, diffuse, numerous branched, to 60 cm, glabrous. Leaves sessile; leaf sheath usually ciliate; leaf blade lanceolate, 6--9 × 1.2--2.8 cm, glabrous or ± hirsute on both surfaces. Involucral bracts 2--4, in fascicles at apex of branches and opposite smaller leaves, sessile, funnelform, 2--2.5 cm, glabrous or ± hirsute, proximal margins partly connate (2--3 mm free), apex retrorsely falcate-acuminate. Proximal branch of cincinni often abortive, sometimes with ca. 2 cm long peduncle but without flowers, distal branch with peduncle to 1 cm and with several flowers; pedicels twisting. Sepals 3.5--4 mm, membranous. Petals pinkish blue, to 1 cm. Capsule subglobose, 3--4 mm, 2- or 3-valved, sometimes only 1 valve containing seed and dehiscent; posterior valve indehiscent. Seeds 1 per valve, brown-black, oblong, ca. 4 mm, flat on 1 surface. Fl. and fr. Jul--Dec.

Humid mountain slopes. Guangdong, S Sichuan (Leibo Xian), Taiwan, E and S Yunnan [India, Indonesia, Philippines; tropical Oceania].

Commelina obliqua Buchanan-Hamilton ex D. Don var. mathewii C. B. Clarke; C. paludosa Blume var. mathewii (C. B. Clarke) R. S. Rao & Kammathy; C. kurzii C. B. Clarke; C. striata Edgeworth.