Richardia 擬鴨舌?屬
型態特徵
Annual or perennial herbs; stems decumbent, rarely ascending, much branched, pubescent. Leaves opposite, penninerved, usually sessile, entire; stipules interpetiolar, adnate to petioles, forming a short sheath, divided into 4 or 5-setae. Terminal heads subtended by (2-)4(–6) involucral leaves. Flowers bisexual; calyx turbinate-globose, scabrous, lobes 6, caducous; corolla funnelform, white, lobes (4-)6, valvate, often tinged pink or lavender; stamens (3-)4 or 6, inserted in corolla tube; ovary (2-)3–4(–6-)celled, ovule 1 per cell, style filiform, trfid at apex, stigmas 3, subglobose; fruit a capsule, with 3 cocci, persistent sepals spreading.
About 15 species in tropical America, 1 species naturalized in Taiwan.