Erect branching annual or biennial, with a slender white taproot. Stems hispid, ± solid, ribbed, sometimes purple tinged, up to 120 cm high. Basal lvs sparsely to moderately hairy, 2-3-pinnate, petiolate; ultimate segments ovate to linear, pinnatisect or serrate, c. 15-40 mm long; stem lvs similar to basal but reduced and segments more often linear. Umbels compound, 2-12 cm diam., usually strongly concave at fruiting; rays numerous; bracts numerous, 1-pinnate, with linear segments; bracteoles 5-9, usually simple and linear to triangular, those of outer umbellets sometimes pinnatisect. Fls numerous, white or tinged pink, 1-7 mm diam., a few central fls sometimes red or purple. Fr. ovoid, dark brown, 2.5-3 mm long; primary ribs sparsely ciliate, secondary ribs spinous; spines pale brown, rarely reflexed at tips.