Description from Flora of China
Herbs to 15 cm tall (including inflorescence), stoloniferous. Stems 2-3 cm, 4-sided, glabrous except for reddish spiny trichomes at nodes. Leaves in a basal or sub-basal rosette; petiole 1-3 cm, both sides sparsely spreading setose, abaxially ± with glandular trichomes; leaf blade elliptic to ovate-elliptic, 3.5-8 × 2-5 cm, papery to subpapery, abaxially sparsely setose on veins otherwise glabrous, adaxially glabrous and minutely tuberculate, secondary veins 3 on each side of midvein, base cordate, margin sparsely denticulate with each tooth having a terminal seta, apex acute. Inflorescences terminal, cymose paniculate, 9-11-flowered; peduncle 4.5-11 cm, glabrous; bracts 2, lanceolate, ca. 6 mm. Pedicel ca. 5 mm but to 1.3 cm in fruit, glabrous. Hypanthium narrowly funnel-shaped, 4-6 mm, 4-sided, glabrous. Calyx lobes lanceolate, ca. 7 × 2 mm, apex acuminate. Petals purple, ovate, ca. 9 × 5 mm, apex with 1 glandular trichome at tip. Longer stamens ca. 1.4 cm; anthers linear, ca. 8 mm, base an obtuse forked spur; connective minutely bulged. Shorter stamens ca. 6.2 mm; anthers ovate, ca. 1.2 mm. Ovary half inferior, obovate, apex truncate and with a membranous crown. Capsule broadly campanulate to almost cup-shaped, ca. 6 mm in diam.; hypanthium exceeding capsule, 4-sided. Fl. Jun.
● Near coast, below hills, grassy areas, shaded damp places; near sea level. Hong Kong.