Revisiting the Hedyotis–oldenlandia Complex in India, With a Note on Scleromitrion

Abstract

In recent years, new generic circumscriptions have been proposed in the Hedyotis–Oldenlandia complex. A comprehensive revision of Indian Hedyotis sensu lato, published in 2004, was based on a broad generic concept for the genus and does not uphold new generic delimitations. Therefore, the present article has been prepared to apply modern generic concepts to the Indian taxa. In India, 102 taxa are currently recorded under the Hedyotis–Oldenlandia complex, belonging to 12 genera (i.e. Debia, Dentella, Dimetia, Edrastima, Exallage, Hedyotis, Involucrella, Kohautia, Leptopetalum, Neanotis, Oldenlandia and Scleromitrion). The characters of these genera have been reviewed and their species enumerated, and consequently, seven new combinations are proposed. Scleromitrion in India is discussed in relation to its phenotypic variation, and a key to the six recognised species is presented.