Shrub or small tree, up to 10 m when mature, armed with axillary spines up to 12-(20) mm long, the longest spines associated with short flowering shoots; stems glabrous, smooth and reddish brown when young but becoming grey when older. Lvs solitary on vigorous vegetative shoots but in fascicles on short shoots; petiole 5-25 mm long, greenish, narrowly winged, grooved above; blade ± deltoid to rhombic, (25)-35-50-(70) × (25)-35-45-(70) mm, deeply lobed, glabrous, dark to mid green above, paler below with primary veins obvious, deeply lobed; lobes 3-7, ascending, oblong, usually entire in lower 1/2 and sparingly and irregularly serrate near the acute apex; stipules of vegetative shoots reniform with prominently toothed margins, those of short shoots smaller and deciduous. Fls many in flat corymbs on leafy short shoots scattered along branches; corymbs subtended by small, leafy, acute bracts; bracts often larger and toothed on younger stems; pedicels 5-11-(18) mm long, often bearing scattered, fine, white hairs. Sepals greenish, finely pilose at least in lower part; lobes triangular to oblong, subacute, becoming reflexed. Petals broadly ovate to orbicular, 4-8 mm diam., rounded to crenulate, spreading, usually white, rarely red-pink. Stamens < petals; filaments white or sometimes pale pink; anthers pink. Style usually 1. Fr. broadly oblong to subglobose, 7-11 mm diam., dark red, shining, crowned by deflexed sepals; nutlets usually 1.