Prostrate to ascending perennial
herbs. Leaves opposite, sessile or shortly petiolate, ± elliptic. Stipular sheath bearing several fimbriae. Flowers bisexual in dense heads surrounded by an involucre of 4 leaves. Calyx lobes persistent. Corolla funnel-shaped, lobes 3-6. Ovary 3-4-locular. Capsule composed of 3-4 cocci, crowned by the persistent calyx, eventually splitting into separate cocci. Derivation of name: after Richard Richardson (1663-1741), English botanist and physician. Worldwide: 15 species in tropical America; naturalised elsewhere. Zambia: 2 taxa. |