Almost scentless, annual or biennial herb sometimes regrowing from old rootstock. Stems erect or ascending, 15-100 cm tall, ribbed, usually glabrous, sometimes sparsely hairy, branched only above to form infl. or sometimes also much-branched from base. Basal and lower cauline lvs appearing shortly petiolate, but usually with very reduced leaflets along sheath, usually narrow-obovate, sometimes ovate, glabrous, mostly 3-pinnatisect, 15-150 × 10-60 mm; ultimate segments filiform, entire, not all in one plane giving a feathery appearance; cauline lvs similar to basal, but apetiolate and above becoming smaller and with fewer segments. Corymb diffuse, of few to many capitula. Involucral bracts glabrous or with a few scattered hairs, 4-7 mm long; margins pale or dark brown, membranous. Capitula c. 30-50 mm diam.; ray florets 12-numerous; ligules white; disc florets numerous, yellow. Achenes 1.7-2.5 mm long, brown, narrow-obpyramidal to cylindric; inner surface with 3 thick ribs; outer surface rugose, with 2, ± globose or slightly elongated glands at apex; corona crenulate, c. 0.1 mm long.