Slender herb up to ± 3 dm. or more tall, from stout stock; stems grooved, stiff, slender, branched above. Lvs on slender petioles up to c. 2 dm. long, us. shorter; sheaths broad, membr., up to ± 2 cm., long. shortly obtusely liguled. Lamina (5)-10-(40) × 5-10 mm.; pinnae 3-6 pairs, spreading, ternately divided into filiform or very narrow-linear acute segs, us. apiculate, up to c. 4 cm. long. Umbels several to few, compound, on slender peduncles up to ± 8c m. long. Bracts foliaceous. Primary rays very slender, unequal, ± 2-5 cm. long; involucral bracts few, short, linear. Umbellules ± 5 mm. diam.; fls small. Fr. 8-9 mm. long, narrow-oblong in outline, compressed. Mericarps thin, 5-winged, lateral wings distinctly > dorsal.

2n = 22

n = 11