Hygrophila ringens (L.) R.Br. ex Steudel

Family

Acanthaceae

Synonyms

Hygrophila angustifolia R.Br., Hygrophila quadrivalvis (Buch.-Ham.) Nees, Hygrophila salicifolia (Vahl) Nees,  Hygrophila erecta (Burm.f.) Hochr.

Vernacular Names

Geographical Distributions

H. ringens has a wide area of distribution: from India and Sri Lanka, through Indo- China, southern China and Japan, to Thailand and the Malesian  region, where there are records from Peninsular Malaysia, Singapore, Java, Borneo, and the Philipines,  but it probably also occurs elsewhere.

Description

H. ringens is an erect or ascending annual or shortliving  herb that can grow up to 90(-120) cm tall. Stem rooting is at the lower nodes and subquadrangular.

Leaves are arranged decussately opposite, simple, linear-oblong to elliptical-oblong or elliptical-obovate, 1-16 cm x 0.5-5 cm, tapering into petiole at base, acute or obtuse at apex, margin is entire to undulate and irregularly marked with cystoliths. Stipules are absent.

Inflorescence is a dense axillary cluster and conspicuously bracteate. Flowers are bisexual with 5-merous.  The sepal is 6-12 mm long and with unequal linear-lance-shaped lobes. The petal is with ventricose, 7-10 mm long hairy tube, 2-lipped where the upper lip is about 5 mm long and 2-fid while the lower lip is about 5 mm long and pale violet-blue or whitish. There are 4 stamens, didynamous and inserted below the middle of the petal tube. The ovary is superior with 2-celled, slender style and often with 2 teeth at apex.

Fruit is a linear-oblong to linear-ovoid, 1-2 cm long loculicidal capsule and many-seeded.

Seed is spherical-ovoid subcompressed which is about 1.5 mm long and long hairy.

Ecology / Cultivation

H. ringens occurs in swampy or periodically humid localities, e.g. at watersides, from sea-level up to 1000 m altitude .

Line Drawing / Photograph

References

1. Plant Resources of South-East Asia No.12(3): Medicinal and poisonous plants 3.