Procumbent annual. Stems sparsely hairy, solid, striate, 5-50 cm long, sometimes purple tinged; hairs deflexed. Basal lvs densely hairy above and below, 1-2-pinnate, petiolate; ultimate segments ovate to lanceolate, pinnatifid and sometimes serrate, 5-20 mm long, usually sessile, sometimes shortly petiolulate; stem lvs similar to basal, but usually shortly petiolate and 1-pinnate. Umbels 5-10 mm diam., subsessile or shortly pedunculate, lf-opposed; rays 2-5, 1-5 mm long, giving the umbel a capitate appearance; bracts 0-(1); bracteoles 2-7, linear. Fls few, white or pinkish, c. 1 mm diam. Fr. ovoid, 2-3 mm long; outer mericarps with straight, spreading, thick-tipped spines; inner mericarps tuberculate.