小狮子草 xiao shi zi cao

Justicia polysperma Roxburgh, Fl. Ind. 1: 120. 1820; Adenosma polysperma (Roxburgh) Sprengel; Hemiadelphis polysperma (Roxburgh) Nees.

Annuals [or perennials] 10-20 cm tall. Stems often prostrate, 4-angled, slightly swollen above nodes, puberulent, soon glabrescent. Petiole to 5 mm; leaf blade oblong-lanceolate to ovate, 2-3.5 × 0.6-1.3 cm, glabrous, base attenuate, margin entire, apex subobtuse. Inflorescences terminal spikes, 1.3-5 cm; bracts imbricate, ovate, elliptic, or obovate, 5-10 × 1.5-3.5 mm, both surfaces densely hirtellous, apex obtuse; bracteoles lanceolate, 3.5-5 × 0.5-1 mm, margin ciliate. Calyx 3.5-6 mm; lobes lanceolate, 2.5-3 mm, unequal, pubescent, apex acuminate. Corolla white, ca. 6 mm; tube ca. 3.5 mm; lower lip ca. 2 mm, 3-lobed, lobes orbicular and subequal; upper lip oblong-ovate, ca. 1 mm, 2-lobed. Stamens 2, slightly exserted; filaments ca. 1 mm, coherent into a membrane near base; anther thecae subequal; staminodes 2, bristlelike, short. Capsule linear-oblong, 5.5-8 mm, pubescent with non-gland-tipped trichomes (also glabrous?), 20-30-seeded. Seeds ca. 1 × 0.5 mm. Fl. Sep-Nov, fr. Oct-Jan. 2n = 32.

Streamsides; below 600 m. Guangdong, Guangxi, Taiwan, Yunnan [Bhutan, India, Myanmar, Sri Lanka, Vietnam].

Hygrophila polysperma is a problematic (e.g., invasive) naturalized weed in some tropical and temperate regions outside of its native range.