Glabrous, short-lived perennial; taproot often thick; stems rather slender, branched, spreading to erect, to c. 100 cm long. Petiole < lamina, especially in uppermost lvs. Lamina of basal and cauline lvs (2.5)-6-22 × (0.5)-1-5 cm, linear, lanceolate-oblong, or oblong, generally with 2 rounded lobes at base, sometimes not lobed, sometimes oblique; margin not or somewhat undulate; base truncate to cordate, rarely cuneate; apex acute to long-acuminate. Infl. usually with lvs in the lower axils; fls in distant whorls of 3-12, ☿, strongly protandrous, extending downwards for ⅔ or more of stem. Pedicels prominently jointed, elongating and deflexed at fruiting. Perianth segments 1.5-2.5 mm long; outer segments lanceolate to ovate, acuminate or aristate, often tinged red, ± spreading at fruiting; inner segments ± broad-ovate, toothed, enlarging at fruiting. Fruiting valves c. 2 × 2 mm (excluding terminal hooked spine), very broadly ovate, strongly reticulate, with c. 5, red, hooked spines 2 mm long on each side; tubercles 0. Nut 2-2.5 mm long, deep glossy brown, acutely angled.