Dwarf to large, solitary, spiny, pleonanthic, monoecious palms. Stem very short, subterranean and geotropic, or erect, columnar or sometimes swollen and spindle-shaped, covered in persistent leaf bases and eventually becoming bare, or armed heavily with spines at first, soon becoming bare, eventually smooth, ringed with leaf scars. Leaves few to numerous, pinnate, marcescent or abscising neatly; sheath disintegrating into a mass of fibres, usually both spiny and finely bristly; petiole short or ± absent, adaxially channelled, abaxially rounded, usually spiny and finely bristly, often with tomentum; rachis usually curved, armed with robust spines, especially along the margins, adaxially channelled near the base, angled distally, abaxially angled or rounded; leaflets numerous, single-fold, linear, acute or shallowly bifid, sometimes plicate, subregularly arranged (rarely) or grouped, usually held in different planes giving the leaf a plumose appearance, usually coriaceous, acute or briefly bifid, adaxially usually glabrous, abaxially glabrous, glaucous or pubescent, transverse veinlets obscure. Inflorescences axillary, interfoliar, shorter than the leaves, arching or becoming pendulous, apparently protandrous, branching to 1 order; peduncle ± oval in cross-section, often elongate, spiny and/or tomentose, rarely unarmed; prophyll tubular, 2-keeled, closely sheathing, usually remaining ± hidden within the leaf sheaths, soon tattering and splitting irregularly, glabrous or densely shaggy hairy, sometimes also spiny; peduncular bract inserted near the prophyll, much larger than the prophyll, persistent, tubular, enclosing the rachillae in bud, strongly beaked, woody, splitting along the abaxial face, then expanded or ± cowl-like, abaxial surface densely shaggy tomentose, and often sparsely to densely spiny, spines sometimes restricted to near the beak, adaxial surface glabrous, often conspicuously pale yellow; rachis longer or shorter than the peduncle, variously spiny, tomentose, or glabrous, bearing few to numerous, spirally arranged rachillae, each subtended by a short triangular bract; rachillae short to elongate, straight or somewhat flexuous, often with a pulvinus (?nectariferous) at the base, usually cream-coloured or yellowish, with a very short to long basal, bare portion, then bearing 1–several, rather distant spirally arranged triads, distal to these a few pairs of staminate flowers, in the distal portion bearing dense spirals of solitary staminate flowers, each flower group subtended by a short-triangular bract, those subtending the staminate flowers forming shallow pits; floral bracteoles small, mostly obscured within the pits. Staminate flowers creamy yellow, usually rather strongly earthy smelling, symmetrical or somewhat asymmetrical, those of the triads briefly stalked, those of distal portion of rachillae sessile; sepals 3, distinct or connate, small, narrow to broadly triangular, sometimes irregularly ciliate; petals 3, distinct except at the very base, much longer than the sepals, ± boat-shaped, ± fleshy, valvate; stamens 6, filaments distinct or briefly adnate to the base of the petals, elongate, inflexed at the tip, anthers ± rectangular, dorsifixed or medifixed, latrorse; pistillode small, trifid. Pollen oblate triangular, occasionally oblate square, usually symmetric; aperture a distal trichotomosulcus or occasionally a tetrachotomosulcus; ectexine semi-tectate or tectate, coarsely perforate, perforations widely separated and indented, or finely reticulate, aperture margin may be slightly finer; infratectum columellate; longest axis 37–62 µm [3/3]. Pistillate flowers larger than the staminate, conic-ovoid; sepals 3, distinct, ± imbricate, broadly triangular or connate in a 3-lobed cupule; petals much longer than the sepals, 3, ± distinct except sometimes near the base, or connate, always with broad, imbricate, distinct margins, except for valvate tips; staminodes 6, united to form a staminodal ring, free, or briefly adnate to the petals, 6-toothed, usually bearing well-developed but empty rounded anthers; gynoecium irregularly ovoid, trilocular, triovulate, variously scaly or tomentose, stigmas 3, fleshy, conspicuous, sometimes violet in colour, reflexed beyond the petals at maturity, ovule laterally attached, orthotropous. Fruit usually 1-seeded, globose, or rarely somewhat pyriform, olive-green to yellow-brown, the stigmatic remains apical; epicarp smooth, or tomentose-bristly, mesocarp fleshy, with abundant short fibres adnate to the endocarp; endocarp very thick, stony, sometimes pitted, dark brown, with 3 pores ± at the equator. Seed basally attached, endosperm homogeneous, sometimes with a central hollow; embryo lateral opposite one of the pores. Germination adjacent-ligular; eophyll not recorded. Cytology: 2n = 30.
Acrocomia aculeata usually avoids ever-wet regions and may be a conspicuous component of savannah and man-made grasslands, the seed sometimes distributed by cattle. Acrocomia hassleri is a palm of ‘cerrado’ in southern Brazil and Paraguay. Acrocomia crispa is endemic to Cuba, where it is confined to calcareous soils throughout the island.
About 34 species have been described, but there are probably far fewer, distributed throughout the West Indies and from Mexico southwards to Argentina. Henderson et al. (1995) accept just two species, Acrocomia aculeata and A. hassleri and Gastrococos crispa (now Acrocomia crispa) however, this may be too sweeping a synonymy.
Acrocomia is considered to be a genus of great potential (Lleras 1985). Starch can be extracted from the stem of A. aculeata; leaves are used as a source of fibre for weaving hammocks and other articles, and in Cuba, leaflets of A. crispa are used for making brooms and for rope fibre. Fruit of many species are used as a source of oil (from the endosperm) and animal food, and they are sometimes sold for human consumption. The cabbage is edible. For medicinal uses, see Plotkin and Balick (1984).