Robust, up to c. 7 dm. tall; stem stout, grooved, branched, on stock up to ± 5 cm. diam. Lvs on stout grooved petioles up to ± 2 dm. long; sheaths broad, membr., tapering to apex, ± ligulate. Lamina 3-6 dm. × 10-15 cm., erect or spreading, 2-3-pinnatisect or -pinnate, linear-oblong to oblong. Primary pinnae 8-10-(14) pairs, distant, broad-oblong to deltoid, (2)-5-10cm. long, coriac., often (3)-5-(10) pairs; petiolules stout, grooved, up to 3 cm. long. Secondary pinnae on petiolules up to c. 1·5cm. long, irregularly deeply subpinnately cut into linear or narrow oblong, obtuse to subacute lobes lacking hair-processes (rarely a lobe may be apiculate). Umbels several to many, compound, (2)-5-(10) cm. diam. Bracts foliaceous; sheaths c. 3-5 × 1-2 cm., open, oblong, tapering to lamina ± 3-5cm. long. Peduncles very stout, deeply grooved. Primary rays 15-20.stout, striate, unequal, ± 1-3 cm. long; involucral bracts up to 1 cm. long, lanceolate to linear-oblong, acute to acuminate. Secondary rays < the 5-10 mm. long, linear-lanceolate involucral bracts. Calyx-lobes minute, triangular; petals white with very narrow brown medial stripe. Fr.(4)-5-6-(7) mm. long, sts > rays. Mericarps strongly 5-ribbed, us. distinctly winged.