Plant forming yellow-green tussocks up to ± l m. × 1 m. Lvs 1-pinnate to irregularly 2-pinnate (sts only 1 secondary pinna developed) up to c. 7 dm. long. Sheaths rather thick, with rather thin margins, ± 25 mm. wide at apex; stipules up to c. 27 cm. × 5-8 mm., tapering to pungent apex. Petioles c. 10-20 cm. × 10-16 mm., finely serrulate on cartilaginous margins; internodes ± 5-6 cm. long. Primary pinnae 2-4, pairs, c 20 cm. × 7 mm., erect; midrib rather obscure, margins serrulate. Secondary pinnae a little shorter, pungent. Stems stout, ribbed, 8 dm. or more long, bracted along most of length; lower bracts empty, yellow. Lower sheaths up to 8 × 1·5 cm., tapering to c. 9 mm., thin, smooth; stipules up to 8 cm. × 2-3 mm., acicular; lamina us. simple, sts bifid, up to c. 22 cm. × 4 mm., acicular. Umbels of male plants distributed from base to apex of peduncles; involucral bracts linear, > rays. Umbels of female plants on peduncles up to 15 cm. long; umbellules crowded on short rays; involucral bracts linear.

2n = 22