Mexican-clover

Richardia scabra, commonly called rough Mexican-clover or Florida pusley, is an annual herb in the Rubiaceae family native to warm-temperate and tropical regions of North America, Central America and South America, and now widely naturalised in the Old World tropics including parts of East Africa. It grows as a weed of disturbed ground including roadsides, vacant lots, lawns, citrus groves, vegetable fields and sandy pine flatwoods, particularly in the southeastern United States. The plant produces prostrate to ascending, branched, hairy stems 10 to 70 centimetres long, often forming low spreading mats. The opposite leaves are sessile to short-petiolate, lanceolate to elliptic, 2.5 to 7 centimetres long, with entire margins, an acute apex and rough hairs on both surfaces; the petiolar bases are connected by an interpetiolar stipule with several bristle-like teeth. Small white tubular flowers are borne in dense terminal head-like clusters subtended by two pairs of leafy bracts; each flower has a six-lobed corolla 4 to 6 millimetres long with hairy interior. Flowering occurs from March through December. The fruit is a leathery schizocarp 3 to 4 millimetres long that separates at maturity into three to four hairy mericarps. The species is considered a significant weed of warm-region agriculture.