Habit: solitary, erect, to 4 m tall, often flowering when appearing stemless but then actually with short subterranean stem. Stem: 1-1.3 cm diam., green, ringed, internodes to 10 cm long, often covered with persistent leaf sheaths. Leaves: 5-7, spreading, pinnate; sheath to 35 cm long, tubular, obliquely open apically and there dark-margined and ragged with a brown ligule 5-8 mm long on either side of petiole, below this margin whitish and green longitudinally striate-nerved; petiole 10-40 cm long, finely grooved and green above, rounded and pale below; rachis to 35 cm long, angled and green above, rounded below with a pale band extending onto sheath; blade to 40 x 15 cm; pinnae 7-9(-13) on each side ofrachis, lower middle ones longest, to 17 x 2-3.5 cm, pinnae progressively smaller toward apex of rachis, 2 basal pinnae smaller, apical pair shortest of all with 2 prominent primary nerves, lanceolate, falcate, long-acuminate, opposite or subopposite, thin-papery, apical 1/3 of each pinna drooping and curling down and under, conspicuously contracted basally and there a hard knob or callus at point of attachment, slightly iridescent gray-green above, paler below, prominent midrib and 2 ± inconspicuous primary nerves on each side of this or primaries absent, secondaries faint and inconspicuous; or when in young and stemless phase leaves finely divided, sheath 3-5 cm long, very open, tubular only near base; petiole 5-8 cm long; blade 20 x 12 cm; pinnae linear-lanceolate, straight, slightly falcate, 7 x 0.8 cm, only a midrib prominent, primary and secondary nerves very faint, inconspicuous. Inflorescences: interfoliar but often infrafoliar in fruit, arising from behind old sheaths, erect. Staminate with peduncle 25-30 cm long, 7-9 mm wide at base and there flattened, 3-4 mm wide at apex and there rounded, erect, greenish or pale in flower; bracts 7-8, prophyll to 3.5 cm long, 2nd bract to 6 cm, 3rd to 9 cm, 4th-7th to 10 cm, 8th to 4 cm, tubular, acute-acuminate, obliquely open apically, longitudinally striate-nerved, drying brownish and papery in flower; rachis to 5 cm long, slightly to strongly curved, lime-green in flower; rachillae 12-15, these to 10-12 cm long, 1.5-2 mm diam., erect, ± stiff, lime-green in flower. Pistillate with peduncle to 40 cm long, erect, 5 mm wide at base and there flattened, 2.5 mm diam. at apex and rounded, pale or greenish in flower, orange in fruit where exposed; bracts similar to those of staminate; rachis 1-3 cm long, greenish in flower, orange in fruit; rachillae 6-8, these to 10 cm long, 1-2 mm diam., erect, ± stiff, slender, longitudinally ridged or angled or finely grooved, slightly spinose-tipped, greenish in flower, orange in fruit. Flowers: Staminate in rather dense spirals, 2-3 mm apart, 3 x 4 mm, depressed-globose, yellow, slightly sunken in elliptic depressions; calyx 0.5 x 2.5 mm, lobed, pale yellow-green, membranous, sepals connate in basal 3/4, rounded apically; petals 4 x 3 mm, broadly ovate, valvate, free nearly to base, strongly incurved apically but not connate, broadly acute; stamens 2-2.5 mm high, outward-leaning, filaments 1-1.5 mm long, pale, anthers 1-1.5 mm long; pistillode 2.25-2.75 mm high, broadly columnar, lime-green. Pistillate in lax spirals, 4-5 mm apart, 3 x 2.5-3 mm, ovoidglobose, slightly sunken in elliptic depressions; calyx 1-1.5 x 22.5 mm, deeply lobed, light green, margins pale and membranous, sepals connate in basal 1/2-3/4, broadly rounded apically; petals 3 x 2-2.5mm, broadly triangular, imbricate nearly to apex, erect apically, obtuse to acute; pistil 2 x 2 mm, globose, flattened apically, green, styles short or lacking, stigma lobes short, pointed, dark green or brownish. Fruits: 7-8 mm diam., globose, black.
Moist to wet, pine-oak forest on the Pacific slope; 1,400-2,000 m elevation.