Hydrocotyle, also called floating pennywort, water pennywort, dollar weed, marsh penny, thick-leaved pennywort and white rot, is a genus of prostrate, perennial aquatic or semi-aquatic plants formerly classified in the family Apiaceae, now in the family Araliaceae.
Description
Water pennyworts, Hydrocotyles, are very common. They have long creeping stems that often form dense mats, often in and near ponds, lakes, rivers, and marshes, and some species in coastal areas by the sea.
Leaves
Simple, with small leafy outgrowth at the base, kidney shaped to round. Leaf edges are scalloped. The leaf surfaces of Hydrocotyle are prime grounds for oviposition of many butterfly species, such as Anartia fatima.
Flowers
Flower clusters are simple and flat-topped or rounded. Involucral bracts at the base of each flower. Indistinct sepals.
Flowering Hydrocotyle leucocephala
Flowering Hydrocotyle vulgaris
Fruits and reproduction
Elliptical to round with thin ridges and no oil tubes (vitta) which is characteristic in the fruit of umbelliferous plants.
The prostrate plants reproduce by seed and by sending roots from stem nodes.
Selected species
There are over 280 species recognised in the genus Hydrocotyle that grow in tropical and temperate regions worldwide. A few species have entered the world of cultivated ornamental aquatics. A list of selected species:
