Robust, solitary, unarmed, pleonanthic, monoecious palms. Stem erect, short, covered with remains of the leaf sheaths. Leaves large, reduplicately pinnate, erect, forming a shuttlecock-like litter-trapping crown, marcescent; sheaths tubular, sparsely tomentose, attenuate distally, the margins smooth, elongate auricles sometimes present; petiole absent or very short, adaxially deeply channelled, abaxially rounded, sparsely tomentose; rachis adaxially ridged, abaxially rounded or flattened; leaflets numerous, regularly arranged, linear, single-fold except at the very tip where sometimes 2-fold, or irregular, broad, composed of many folds, the midribs strong, the tips briefly bifid, adaxially glabrous, abaxially minutely dotted, bearing several large, brown ramenta along the midrib, transverse veinlets obscure. Inflorescences solitary (very rarely possibly multiple; Dransfield and Beentje 1995b), interfoliar, branching to 2 orders, protandrous or protogynous; peduncle elongate, semicircular or crescent-shaped in cross-section, sparsely tomentose; prophyll inserted some distance above the base of the peduncle, large, flattened, narrow, elliptical, beaked, strongly 2-keeled, coriaceous, sparsely tomentose, splitting longitudinally along the abaxial face, persistent; peduncular bract similar to the prophyll but not 2-keeled, caducous or persistent, incomplete peduncular bracts several, membranous, relatively large, triangular, open; rachis shorter or longer than the peduncle, bearing spirally arranged, short triangular bracts each subtending a first-order branch; proximal first-order branches with a short bare portion, distally bearing 1–2 branches; rachillae ± straight, rather thick, elongate, bearing spirally arranged, very slightly sunken triads, each subtended by a thick, coriaceous, low triangular bract through most of the rachilla length, or bearing more crowded, more sunken pairs of staminate flowers towards the rachilla tips, or distal rachillae entirely staminate; floral bracteoles conspicuous, ± triangular. Staminate flowers symmetrical; sepals 3, distinct, imbricate, coriaceous, triangular, strongly keeled; petals 3, distinct, triangular, about 3 times as long as the sepals, coriaceous; stamens 6, filaments slender, distinct or briefly connate at the base, anthers elongate, basifixed, latrorse; pistillode columnar, deeply grooved, ± equalling the stamens in length. Pollen ellipsoidal asymmetric, occasionally oblate triangular; aperture a distal sulcus, less frequently a trichotomosulcus; ectexine tectate, coarsely perforate, finely perforate-rugulate or foveolate, aperture margin similar, or finer; infratectum columellate; longest axis ranging from 35–55 µm [2/2]. Pistillate flowers ovoid, much larger than the staminate; sepals 3, distinct, broadly imbricate, triangular, keeled, coriaceous, shiny; petals 3, distinct, imbricate with valvate tips, triangular, coriaceous, striate; staminodes 6, distinct, tooth-like; gynoecium ovoid, with a conspicuous beak, unilocular, uniovulate, stigmas 3, large, triangular, appressed in bud. Fruit ellipsoid, yellowish brown at maturity (Masoala madagascariensis), beaked and with stigmatic remains apical; epicarp smooth; mesocarp fleshy; endocarp composed of coarse longitudinal fibres. Seed depressed globose, basally attached; endosperm homogeneous; embryo basal. Germination adjacent-ligular; eophyll bifid. Cytology: 2n = 32.