Monographs Details: Riedlea villosa Britton & P.Wilson
Authority: Britton, Nathaniel L. Flora Borinqueña.
Description:Species Description - An attractive, low, herbaceous, but slightly woody, purple-flowered, hairy plant, inhabiting sandy soil at lower and middle altitudes in moist parts of Porto Rico, distributed through the Greater Antilles, in Trinidad, and in tropical continental America. We have learned of no English name for it, nor have we seen it anywhere in cultivation.
The generic name Riedlea first published in 1803, by the French botanist Ventenat, in his elegant folio volume "Choix des Plantes", where our typical species is illustrated, commemorates Anselme Riedle, a French botanical explorer. The genus consists of about 20 species, natives of tropical and subtropical America, only one of them Porto Rican. There are herbs, or low shrubs, with alternate, toothed leaves, and rather small, clustered flowers, each flower subtended by 3, small bracts. There are 5 sepals, 5, flat petals, 5 stamens with filaments united at the base; the ovary is 5-celled, surmounted by 5 styles. The 5-celled, capsular fruit splits to release the seeds.
Riedlea villosa (long-hairy) is about 0.5 meters high, or lower, branched, upright, or ascending. Its thin, ovate, toothed leaves are short-stalked, from 5 to 7 centimeters long. The clusters of flowers are axillary and terminal; the bracts are longer than the calyx, the purple petals from 7 to 10 millimeters long, the capsule about as long as the calyx, or shorter.
Sida villosa Miller, Gardeners Dictionary, edition 8. 1768.
Melochia hirsuta Cavanilles, Dissertationes 6: 323. 1788.
Riedlea serrata Ventenat, Choix des Plantes, t. 37. 1803.
Riedlea hirsuta de Candolle, Prodromus 1: 492 1824.
Riedlea villosa Britton and Wilson, Scientific Survey of Porto Rico and the Virgin Islands 6: 551. 1930.