Diodia
Diodia is a genus of flowering plants in the family Rubiaceae. It was described by Carl Linnaeus in 1753. The genus is found from southern and eastern United States, South America, Central America, Mexico, the West Indies and tropical Africa.
Other buttonweeds
Many species of Diodia have been transferred to a closely related genus Diodella, and therefore the name buttonweed also applies to these species. There are also many species of false buttonweeds in the related genus Spermacoce. Abutilon theophrasti in the family Malvaceae is also known by the common name of buttonweed.
Species
Diodia aulacosperma K.Schum. - Socotra, Somalia, Kenya, Tanzania Diodia barbata DC. - Guyana, Dominican RepublicDiodia barbigera Hook. & Arn. - MexicoDiodia blepharophylla Standl. - MexicoDiodia discolor DC. - French GuianaDiodia flavescens Hiern - Angola, ZambiaDiodia indecora DC. - MexicoDiodia kuntzei K.Schum. - Venezuela, Bolivia, Peru, Brazil, Argentina, Paraguay Diodia lithospermoides K.Schum. - Peru Diodia macrophylla K.Schum. - Brazil, ParaguayDiodia microcarpa K.Schum. ex Glaziou - Brazil Diodia mitens Bello - Puerto RicoDiodia othonii Rizzini - Brazil Diodia paludosa Kuntze - ParaguayDiodia perforata Urb. - HaitiDiodia rubricosa Hiern - Ghana, Ivory Coast, Liberia, Nigeria, Sierra Leone Diodia saponariifolia K.Schum. - Central and South AmericaDiodia saponarioides C.Presl - Mexico, Brazil, Argentina, ParaguayDiodia scandens Benth. - Western, Central, and Eastern AfricaDiodia simplex Sw. - Cuba, JamaicaDiodia verticillata Vahl - Brazil, Lesser Antilles Diodia virginiana L. - Virginia buttonweed - south-central and south-eastern United States from Texas to Kansas, east to Florida and New Jersey; also Connecticut, Cuba and Nicaragua. Naturalized in Japan, Taiwan and northern California