Prostrate to erect, leafy, often spiny
shrubs or trees up to 8 m tall, with actinorhizal root
nodules. Leaves decussate, each subtending 2 serial
buds. Leaf margin entire, spines with a node close
to spine base. Flowers perfect, 4-5(-6)-merous,
in 1-3-flowered cymes; hypanthium campanulate
to urceolate, glabrous, deciduous; sepals valvate,
deltoid, adaxially carinated, at anthesis somewhat
reflexed; petals cucullate; stamens opposite to petals,
filaments erect, cylindrical, anthers 4-sporangiate,
introrse; disc ring-like, more or less lobed, encir-
cling the ovary at bottom of hypanthium; ovary
semi-inferior, 3-locular, locules 1-ovulated, style
subcylindrical, stigma with three lateral receptive
areas. Fruit an explosive capsule.