Mitracarpus

Erect or prostrate annual or perennial herbs with 4-angled stems. Leaves opposite; blades linear-lanceolate to ovate or broadly elliptic; stipules connate with petioles to form a fimbriated sheath. Flowers not heterostylous or only slightly so, in dense, spherical, sessile, terminal or axillary heads. Calyx: tube obconic, obovoid or subglobose; teeth 4-5, 2 often longer, sometimes with minute supplementary ones between. Corolla salver-shaped or funnel-shaped; tube often with an internal ring of hairs; lobes 4; throat glabrous or hairy. Stamens arising in throat; anthers included or exserted. Disc fleshy. Ovary 2(3)-locular; ovules solitary in each locule, attached by the middle to septum; style short or long, divided into 2 short, linear branches. Fruit a thin circumscissile capsule, the upper part splitting off together with calyx lobes, septum persistent. Seeds oblong or globose, ventral face divided into 4 distinct areas; endosperm fleshy.