Hygrophila madurensis - Madurai Swampweed

Madurai Swampweed is a small herb, 10-35 cm tall, branchlets prostrate, arising from base; stems quadrangular, swollen at nodes. Leaves are opposite, in alternating perpendicular pairs, thin, membranous, hairless, lanceshaped or oblong-inverted-lanceshaped, base wedge-shaped, margin minutely rounded-toothed, pointed or nearly so at tip, lateral nerves 5-7 pairs, prominent below. Leaf-stalks are 2-3 mm long. Flowers are borne in open dichasial cymes in leaf-axils, usually shorter than leaves; primary flower-cluster-stalk about 5 mm long; internodes about 3 mm long; bracts linear, pointed, 2-5 mm long; flower-stalks about 1 mm long. Sepals are 5, free, nearly equal, linear, pointed, 4-5×1 mm. Flowers are purple, two-lipped, 5-10 mm long; tube funnel-shaped, broad, velvet-hairy inside; upper lip bifid, notched, lobes rounded; lower lip trifid, lobes blunt, rounded. Stamens are 4, filaments linear, thread-like, hairless, 2-4 mm long; anthers oblong, ellipsoid, 1.0-1.3 mm long. Capsules are linear-oblong, flat, stalkless, 6-8 mm long. Madurai Swampweed is found in marshy localities and wetlands, and is endemic to Tamil Nadu. Flowering: November-March.