5. Hygrophila erecta (N. L. Burman) Hochreutiner, Candollea. 5: 230. 1934.
小叶水蓑衣 xiao ye shui suo yi
Ruellia erecta N. L. Burman, Fl. Indica, 135. 1768; Hygrophila phlomoides Nees var. roxburghii C. B. Clarke.
Perennials to 1 m tall. Stems erect, 4-angled, 2-sulcate. Petiole (0-)3-5 mm, sulcate, hispid; leaf blade elliptic, obovate, or oblong, 2-9 × 1-3 cm, with numerous cystoliths, both surfaces densely strigose, secondary veins 8-15 on each side of midvein and abaxially prominent, base decurrent onto petiole, margin entire or slightly undulate, apex acute to obtuse. Flowers several clustered in leaf axils, sessile; bracteoles linear-oblong, ca. 6 mm, densely hispid-ciliate. Calyx ca. 1.1 cm, 5-lobed to middle; lobes linear-lanceolate, densely white hispid-ciliate. Corolla purplish blue, 1.8-2.2 cm, pilose; tube basally cylindric for ca. 5 mm and ca. 2 mm wide then gradually widened to ca. 6 mm at mouth; limb 2-lipped; lower lip oblong, 3-lobed, lobes ovate and ca. 2 × 2 mm; upper lip triangular, 2-lobed. Stamens 4; filaments glabrous, longer pair ca. 6 mm, shorter pair ca. 3 mm; anther thecae ca. 2 mm. Ovary glabrous; style pilose. Capsule 1.2-1.5 cm. Seeds blackish brown, ca. 1.5 × 1 mm, pubescent.
Wet places; below 1000 m. Guangdong, Hainan, Yunnan [India, Laos, Myanmar, Thailand, Vietnam].