Stems solitary, robust, armed, covered with persistent leaf bases or bare. Leaves: petioles armed with needlelike prickles; petiole margins unarmed; blade pinnate, armed with prickles; plication reduplicate; segments regularly arranged, apices acute. Inflorescences axillary within crown of leaves, paniculate, arching, becoming pendulous in fruit, with 1 order of branching; prophyll short; peduncular bract woody, prickly, splitting abaxially, curling downward; rachis armed with prickles. Flowers unisexual, sessile, borne in triads of 1 pistillate flower flanked by 2 staminate flowers, staminate flowers borne singly along distal portions of rachillae. Staminate flowers: sepals 3, free; petals 3, valvate, leathery, basally connate, leathery; stamens 6, free; anthers rectangular; pistillode with 3 minute lobes. Pistillate flowers: sepals 3, imbricate, free; petals 3, imbricate, basally connate or nearly free; staminodes well -developed, bearing short, sterile anthers; pistils 1, large, tomentose; ovules 3; styles indistinct; stigmas 3. Fruits drupes, globose; exocarp brownish green, thin, pubescent near fruit apex [bristly]; mesocarp fleshy, oily; endocarp thick, bony, with 3 equatorial germination pores. Seeds irregular; endosperm homogeneous; embryo lateral; eophyll undivided [2-cleft], linear-lanceolate. nx = 15. Although as many as 30 species of Acrocomia have been described, a recent study (A. Henderson et al. 1995) recognized only two, A. aculeata (Jacquin) Loddiges (including A. totai Martius) and A. hassleri (Barbosa Rodrigues) W. J. Hahn. I maintain A. aculeata and A. totai as two separate species, both of which are cultivated in Florida, where the latter species is naturalized. A general comparison of these two species was made by B. Peterson (1991) in which he noted that the eophyll of A. aculeata is 2-cleft and that of A. totai is undivided. He also found several subtle differences between these species when mature. For example, the trunk spines of A. totai are ca. 12--13 cm and those of A. aculeata are ca. 6--10 cm. Clearly, additional study is warranted to resolve the prickly systematic problems in this genus.