30-50 cm high herb, with short stem and many long fibrous roots, floating or sometimes rooting. Leaves glabrous, 45-110 x 50-100 mm; broadly ovate to rhomboid, entire, obtuse, base cuneate or rounded. Petiole glabrous and spongy, 6-30 cm long, with a fusiform bulbous portion about the middle. Peduncle spongy. Inflorescence (3-)6-15 (-35) flowered. Flowers lilac, tinged blue, withering soon. Perianth c. 57 mm long, tube green, glandular; segments 34-40 mm long, obovate to ovate-oblong, posterior segment with a yellow spot. The longer 3 stamens c. 21 mm, filaments curved, glandular hairy;shorter filaments c. 6 mm long, glabrous; anthers purple-blue. Ovary ovoid, glabrous; style glandular; stigma 3-lobed, glandular.

Fl. Per.: May July.

Type: Habitat in Brazil.

Distribution: Native of Brazil, introduced and naturalised in many tropical countries.

The ‘Water Hyacinth’ is very common in the Punjab, especially in the Gujranwala district, inhabiting vast marshy areas, propagating by stolons and multiplying very fast. It covers vast areas of water forming impenetrable growth. The lilac flowers are a beautiful sight during the flowering season. Difficult to eradicate and due to its quick growth, it has become a troublesome weed around Lahore, especially in the Gujranwala district. The plant is rich in potash.