Solitary, short-trunked, unarmed, pleonanthic, dioecious palm. Stem erect, eventually becoming bare, internodes short, obscured at first by a dense network of long, coarse, straight, sheath fibres (piassava). Leaf pinnate; sheath soon disintegrating into a mass of long coarse fibres resembling horse hair; petiole short, adaxially channelled, abaxially with a covering of white waxy indumentum; leaflets regularly arranged, the basal-most very narrow, the middle lanceolate, the terminal very short, midrib prominent, a pair of marginal veins less prominent, transverse veinlets inconspicuous. Inflorescences, the staminate and pistillate dissimilar; staminate short, racemose, recurved at anthesis, branched to 1 order; peduncle moderate, rounded, glabrous; prophyll tubular, short, shallowly 2-keeled, rounded to a shallow point, splitting apically; complete peduncular bracts l, similar to the propyll but longer, incomplete peduncular bracts few 3–5, large or small and shallow; rachis slightly longer than the peduncle, bearing spirally arranged, short, terete branches, each subtended by a small pointed bract; first-order branches each bearing up to 4 staminate flowers, subtending bracts small, pointed, membranous or not evident. Staminate flowers with a conspicuous terete stalk; perianth consisting of a low membranous rim or absent; floral receptacle rounded bearing 400–650 stamens, filaments short, anthers elongate, basifixed, latrorse; pistillode rarely present, if so then minute, carpelliform. Pollen ellipsoidal, usually with either slight or obvious asymmetry; aperture a distal sulcus; ectexine semi-tectate, reticulate, aperture margin similar; infratectum columellate; longest axis ranges from 75–80 µm [1/1]. Pistillate inflorescence head-like, unbranched; prophyll tubular, short, 2-keeled laterally, flattened, pointed, splitting along one side; peduncular bracts 15–25, the first complete, tubular, rounded, with a short pointed tip, splitting apically on one side, subsequent bracts incomplete. Pistillate flowers spirally arranged, closely appressed, each subtended by a bract; sepals ± 4, narrow, elongate; petals ± 4, like the sepals but longer and somewhat wider, variously wrinkled; staminodes 30–50; gynoecium consisting of usually 6–8 carpels, connate laterally, ovarian part terete, tapering into an elongate, cylindrical style and 6–8, curly, elongate stigmas, conduplicately folded, bearing stigmatoid tissue along the margins. Fruits borne in large head-like clusters, each fruit rounded, covered in large, pointed warts, stylar remains terminal, forming a large beak; epicarp with short, close fibres, mesocarp fibres fine, endocarp shell-like with adherent fibres enclosing each seed. Seed ± kidney-shaped, hilum basal, raphe fibres parallel, ascending, with short branches forming grooves in the endosperm, endosperm homogeneous, very hard; embryo lateral near the base. Germination remote-ligular; eophyll pinnate. Cytology: 2n = 36.