ARISTOLOCHIACEAE (Birthwort Family)

Plants perennial herbs or lianas (shrubs elsewhere). Leaves alternate, simple, with petioles. Flowers perfect, epigynous. Calyx usually petal-like (not green), often united into a straight or contorted tube toward the base, expanded into 3 shallow or deep lobes at the tip. Corolla absent (reduced to small scales elsewhere). Stamens (5)6 or 12. Pistils 1 per flower. Ovary inferior, 3–6-locular, the ovules numerous. Style 1, the stigmas 3–6. Fruits capsules with numerous seeds. Five genera, about 600 species, nearly worldwide but most diverse in tropical and subtropical regions.