Hygrophila auriculata (Schumach.) Heine

Perennial, subshrubby herbs with sharp axillary spines up to 4 cm long. Stems up to 1 m or more tall, mostly unbranched, with bristly hairs, nodes thickened. Leaves sessile or nearly so, simple, in spurious whorls of 6 spines and 8 leaves, the outermost leaves longest, lanceolate to linear-lanceolate, 5-10(-15) cm long, 1.5-2.5 cm wide, hairy when aerial, base tapering, margins minutely toothed, tips pointed; spines up to 3 cm long. Flowers sessile or nearly so, in axillary whorls, usually surrounded by spines; bracts and bracteoles leafy, ±1.5 cm long. Sepal tube 4-lobed; lobes unequal, the longest linear-lanceolate, ±1 cm long. Petals blue, purple or sometimes pink, glabrous, up to 2.5 cm long; lobes rounded to pointed, the middle lobe of the lower lip with a yellow spot. Stamens: filaments in 2 pairs, 1 pair ±5 mm long, the other pair ±10 mm long; anthers unequal, up to 3 mm long. Capsules ± terete, linear-oblong in outline, ±1 cm long. Seeds 4-8, almost spherical, ±3 mm in diameter; retinacula long and curved.

Wet places, often brackish, littoral, estuarine. Does well at the edges of seasonal pools or other stagnant water bodies, at elevations from 900-2,100 metres in Tanzania.

The leaves are used as a potherb. They are cooked with other vegetables. The dried leaves are used for a tea drink. A vegetable salt is prepared from the ashes. The seeds are soaked overnight and then eaten in the morning. The leaves and stems can be sun-dried.

Plants can be grown from seeds.