Massive, solitary, armed, hapaxanthic, hermaphroditic, tree palms. Stem erect, closely ringed with leaf scars sometimes in distinct spirals. Leaves induplicate, costapalmate, marcescent in immature individuals, tending to abscise under their own weight in trunked individuals; sheath sometimes with lateral lobes, later sometimes with a conspicuous triangular cleft below the petiole, the margins tending to erode into fibres; petiole massive, long, covered with caducous indumentum, adaxially deeply channelled, abaxially rounded, margins with well-defined teeth; adaxial hastula well developed, abaxial hastula rather irregular; blade regularly divided to ca. 1/2 its radius into single-fold segments, these in turn shallowly divided along the abaxial folds, filaments present at upper folds in young leaves, segments with prominent longitudinal veins, abundant transverse veinlets and caducous floccose indumentum along the folds, indumentum more abundant abaxially. Inflorescences above the leaves, subtended by reduced, scale-like leaves, forming a massive, compound inflorescence-like structure; individual inflorescences emerging from the mouths of the bract-like leaves or through an abaxial split, branched to the third order, all branches ending as rachillae; prophyll of inflorescences 2-keeled, empty; bracts tubular, the proximal 0–several empty, other bracts inconspicuous, triangular, each subtending a first or higher order branch; rachillae bearing spirally arranged, adnate cincinni of up to 10 flowers; floral bracteoles minute. Flowers borne on short stalks formed by the base of the calyx and the receptacle; calyx tubular basally, with 3 low, triangular lobes; petals ± boat-shaped, basally imbricate, the margins usually inrolled, stamens 6, the 3 antesepalous free, the 3 antepetalous adnate basally to the petals, filaments tapering from a fleshy base; anthers short, somewhat sagittate basally, medifixed, latrorse; gynoecium tricarpellate, syncarpous, triovulate, ovary globose, distinctly 3-grooved, style elongate, slightly 3-grooved, stigma scarcely differentiated, ovule hemianatropous. Pollen ellipsoidal, usually slightly asymmetric; aperture a distal sulcus; ectexine tectate, reticulate or foveolate-reticulate, aperture margin psilate or scabrate; infratectum columellate; longest axis 28–40 µm [3/8]. Fruit globose, single-seeded with basal stigmatic remains; epicarp smooth, mesocarp fleshy, endocarp thin, usually remaining attached to the seed. Seed globose, with basal hilum, and shallow grooves corresponding to the rapheal bundles, endosperm homogeneous, with or without a central hollow; embryo apical. Germination remote-tubular; eophyll entire, lanceolate. Cytology: 2n = 36.