Moderate, solitary or clustered, unarmed, pleonanthic, dioecious palms. Stem robust or rarely rather slender, erect or procumbent, internodes short, covered with a mass of fibres and petiole bases, when bare marked by spiral, triangular, often pitted leaf scars. Leaves numerous or rarely few, erect, arching, evenly pinnate; marcescent; sheath tubular, sometimes with a large ligule opposite the petiole, becoming fibrous; petiole short, lacking, or rarely elongate, shallowly channelled adaxially, rounded abaxially, margins rounded or sharp; rachis triangular in section, with greyish brown scales abaxially, leaflets regularly arranged in one plane, or irregularly arranged and held in different planes to give the leaf a plumose appearance, subopposite, single-fold, pointed, often pinched in at the base, usually smaller basally and distally, glossy dark green adaxially, paler and duller beneath; tomentose abaxially along a conspicuous midrib, transverse veinlets conspicuous. Inflorescences interfoliar, staminate and pistillate dissimilar; staminate unbranched; peduncle short; prophyll short, tubular, 2-keeled laterally, broadly pointed, splitting apically; complete peduncular bracts 1, like the prophyll but longer, splitting abaxially, persistent above the inflorescence, subsequent peduncular bracts several (4–5), incomplete, spirally inserted below the flowers. Staminate flowers in groups of 4, sessile or with a conspicuous common stalk, usually lacking a subtending into sepals and petals at maturity (but see Uhl and Moore 1977b); stamens 36–900 or more, filaments erect, awl-shaped, anthers elongate, latrorse; pistillode lacking. Pollen ellipsoidal, usually with slight or, occasionally, with obvious asymmetry; aperture a distal sulcus; ectexine tectate, coarsely perforate, or perforate-rugulate, aperture margin slightly finer; infratectum columellate; longest axis 72–90 µm [3/7]. Pistillate inflorescence head-like; peduncle short, dorsiventrally flattened; prophyll and first peduncular bract as in the staminate, subsequent peduncular bracts numerous, larger than in the staminate, sometimes in series, elongate, pointed, ± covering the flowers. Pistillate flowers asymmetrical, each subtended by a pointed bract, spirally arranged, closely appressed; sepals 3 or more, triangular, ± elongate; petals 4–10, long, narrow, variously folded and wrinkled; staminodes numerous, 35 or more, like the stamens but irregular in size; gynoecium of 4–10 united carpels, ovarian part short, rounded, stigma long, narrow, cylindrical, styles as many as the carpels, long, narrow, conduplicately folded with stigmatoid tissue along the margins, ovules 1 per carpel, hemianatropous or anatropous. Fruit clusters, individual fruits ± rounded, 4–10-seeded, covered with large, woody, pointed warts, stylar remains terminal; epicarp woody, mesocarp fibrous, endocarp surrounding each seed bony or shell-like, bifacial adaxially with round basal projection, rounded abaxially. Seed ±kidney-shaped, basally or laterally attached, hilum round, median to basal, raphe branches numerous, laterally ascending and anastomosing; endosperm homogeneous, hard (vegetable ivory), embryo basal or lateral. Germination remote-ligular; eophyll pinnate. Cytology: 2n = 36.