Description from Flora of China
Salomonia cantoniensis var. edentula (Candolle) Gagnepain; S. edentula Candolle; S. subrotunda Hasskarl.
Herbs annual, erect, 5-25 cm tall. Roots slender, fragrant. Stem thin, multibranched, 3-winged, glabrous. Petiole 1.5-2 mm; leaf blade ovate-cordate or cordate, 5-16 × 5-12 mm, membranous, glabrous, 3-veined, base cordate or truncate, margin entire or slightly undulate, apex obtuse, mucronate. Spike terminal, 1-6 cm, elongated after anthesis. Flowers very small, 2-3 mm, sessile; bracts caducous, very small. Sepals 5, persistent, connate at base, linear-subulate, 0.4-0.5 mm. Petals pink-purple; lateral petals ca. 2.5 mm; keel ca. 3 mm. Filaments ca. 2 mm, united into an open sheath, inside of sheath arachnoid; anthers connate. Ovary reniform, ca. 1 mm in diam., margin narrowly triangular-denticulate; style ca. 2.5 mm; stigma slightly lobed. Capsule reniform, ca. 1 mm, ca. 2 mm in diam., both lateral margins pointedly triangular-denticulate; surface of capsule with protruding reticulations. Seeds 2, black, shiny, ovoid, ca. 1 mm in diam. Fl. Jun-Aug, fr. Aug-Oct.
Material with the margin of the capsule ± smooth (almost no denticulations) has been separated as Salomonia cantoniensis var. edentula, but as the degree of denticulation in this species is variable and as S. cantoniensis var. edentula is in all other aspects identical to S. cantoniensis, the variety is not here recognized.
Forests, forest margins, shrub forests, grasslands on hills and mountain slopes; 600-1500 m. Fujian, Guangdong, Guangxi, Guizhou, S and SE Yunnan, Zhejiang [Bhutan, Cambodia, India, Indonesia, Laos, Malaysia, Myanmar, Nepal, Philippines, Thailand].