Moderate to massive, solitary or clustered, unarmed (except for sharp fibres of leaf sheaths), pleonanthic, monoecious palms. Stem erect, densely covered in fibrous leaf sheaths, when mature becoming bare except rarely (Oenocarpus circumtextus) fibrous network persistent, leaf scars smooth, flush with stem basally, swollen and prominent distally, a small mass of slender roots sometimes present basally. Leaves pinnate or entire-bifid, spirally arranged or distichous, suberect when young, becoming spreading; sheath tightly clasping but not forming a distinct crownshaft, splitting at least partially opposite the petiole, thick, leathery, lightly furrowed adaxially, glabrous or scaly abaxially, disintegrating marginally into masses of hair-like black or brown fibres and sometimes also fewer stout, sharp, knitting-needle-like fibres; petiole short, rarely elongate, channelled adaxially, rounded abaxially; leaflets regularly arranged in one plane or irregularly clustered, broadly lanceolate, acute to tapering, single-fold, blade adaxially glabrous, sparsely to densely abaxially glabrous or covered with persistent, shining, pale, straw-coloured or brownish, membranous, orbicular to transversely elliptical or sickle-shaped or needle-like medifixed scales, or with scattered, whitish, waxy, sickle-shaped hairs, midrib largest but other intermediate veins also large, transverse veinlets not evident. Inflorescences interfoliar in bud, becoming infrafoliar, hippuriform (shaped like a horse’s tail), protandrous, branched to 1 order laterally and abaxially, adaxial branches absent; peduncle short to elongate, flattened, tomentose; prophyll short, wide, adaxially flattened, 2-keeled, splitting abaxially, margins broadly toothed; peduncular bract much longer than the prophyll, terete, beaked, scaly; rachis longer than the peduncle but short, tapering, bearing spirally arranged, very small, slightly sunken, pointed to scalloped, thin bracts, adaxial ones abortive and evident only in young stages, lateral and abaxial bracts subtending rachillae; rachillae ± flexuous, pendulous, short to elongate, straight to slightly undulate, slender, tapering, bearing triads of flowers basally and pairs to single staminate flowers distally, rarely completely staminate, flowers borne in shallow depressions; rachilla bracts low, rounded with a short point, slightly sunken; floral bracteoles similar to rachilla bracts. Staminate flowers asymmetrical, pointed in bud; sepals 3, distinct, valvate, imbricate or briefly connate basally; petals 3, distinct, ovate, somewhat asymmetrical, valvate; stamens 6 or (7–8) 9–20, filaments terete, slender, straight or variously curved and bent, distinctly inflexed at the apex, anthers elongate, basally free and sagittate, rounded or blunt apically, dorsifixed, versatile, connective not extending above locules, latrorse; pistillode bifid or trifid. Pollen ellipsoidal, occasionally oblate triangular, with slight or obvious asymmetry; aperture a distal sulcus, occasionally, a trichotomosulcus; ectexine tectate, finely or coarsely perforate-rugulate, aperture margin finer; infratectum columellate; longest axis 38–56 µm [6/9]. Pistillate flowers shorter than the staminate; sepals 3, distinct, suborbicular, imbricate, hooded; petals 3, distinct, imbricate except for valvate apices when young, otherwise like the sepals; staminodes tooth-like or lacking; gynoecium ovoid, briefly stalked, unilocular, uniovulate, style short, cylindrical, bearing 3 fleshy stigmas, reflexed at anthesis, papillose adaxially. Fruit ellipsoidal to globose, dark purple when ripe, perianth persistent, stigmatic remains apical to slightly eccentric; epicarp smooth or minutely pebbled, waxy, mesocarp fleshy, oily, with internal fibres adnate to and covering the seed, endocarp apparently lacking. Seed ovoid-ellipsoidal to globose, hilum basal, raphe lateral, branches parallel, indistinct, endosperm homogeneous and striate, or ruminate, with central cavity; embryo basal, very large, extending through the endosperm into central cavity. Germination adjacent-ligular; eophyll bifid. Cytology: 2n = 36.