Melanthera (common name: squarestem), is a genus of perennial flowering plants in the family Asteraceae, native to North and South America, as well as Africa, Asia and Oceania, including Hawaii. The most common species of this genus is Melanthera biflora, found in the coastal areas and islands of the tropical belt of the Indo-Pacific region. Together with Portulaca oleracea, Ipomoea pes-caprae and Digitaria ciliaris, Melanthera biflora is usually one of the first species colonizing degraded or altered environments in tropical zones of the planet. Despite their general hardiness, leaves of Melanthera species are often attacked by rusts such as Uromyces columbianus and Uromyces martinii.

Taxonomy

There are difficulties regarding the classification of this genus for its affinities are uncertain. Further studies are needed to clarify its taxonomic and phylogenetic relationships.

Species

This is a list of species.