Alternanthera sessilis : Mukunuwenna

Alternanthera sessilis is an aquatic plant known by several common names, including Matikaduri in Assamese, ponnanganni (in Tamil), ponnaganti aaku (in Telugu), honnagone (in Kannada), mukunuwenna (in Sinhala), sessile joyweed and dwarf copperleaf. It is used as a vegetable specially in Sri Lanka and some Asian countries

The plant occurs throughout the tropical and subtropical regions of the Old World. It has been introduced to the southern United States, and its origins in Central and South America are uncertain

This is a perennial herb with prostrate stems, rarely ascending, often rooting at the nodes. Leaves obovate to broadly elliptic, occasionally linear-lanceolate, 1–15 cm long, 0.3–3 cm wide, glabrous to sparsely villous, petioles 1–5 mm long. Flowers in sessile spikes, bract and bracteoles shiny white, 0.7–1.5 mm long, glabrous; sepals equal, 2.5–3 mm long, outer ones 1-nerved or indistinctly 3-nerved toward base; stamens 5, 2 sterile. In the wild it flowers from December until March.

The plant grows wild, but is also cultivated for food, herbal medicines, as an ornamental plant (red variety, as a hedging plant), in the aquarium trade (though it only grows submersed for short periods), and as poultry feed.

In certain regions of South East Asia, the leaves and young shoots are consumed as vegetables, in Karnataka, Andhra Pradesh and Tamil Nadu, the leaves, flowers and tender stems are consumed as vegetables.

As a herbal medicine, the plant has diuretic, cooling, tonic and laxative properties. It has been used for the treatment of dysuria and haemorrhoids.The plant is also believed to be beneficial for the eyes, and is used as an ingredient in the making of medicinal hair oils and Kajal (kohl).

This species is classified as a weed in parts of the southern States of the USA. It is usually (but not always especially in areas of high humidity where it can even be a garden weed) found in wet or damp spots.

It is an excellent bee forage plant. 

Alternanthera sessilis is part of the catalog of ayurvedic medicinal plants of Sri Lanka.