Stems clustered or less often solitary, mostly slender and climbing, occasionally non-climbing and then either short and subterranean or free standing. Leaves 10-60, pinnate, spiny; sheaths closed in climbing stems, open in non-climbers, variously hairy and spiny, hairs of young sheaths soon wearing off; sheath spines scattered or densely arranged (rarely absent), or arranged in rows, occasionally hairy on margins, variously shaped and colored, sometimes arranged in overlapping, interlocking rings and forming chambers; sheath apices usually extended above point of insertion of petiole into an inconspicuous or prominent ocrea; knees present in climbing stems; flagella present in climbers, whiplike and armed with small, grapnel-like spines; cirri present in few species (and then flagella absent, and vice versa); pinnae variously arranged and shaped, occasionally whitish or gray on abaxial surfaces. Plants dioecious. Inflorescences usually elongate, branched to 3 orders, male inflorescences more branched than female ones; branches and rachillae covered with overlapping bracts with clawed spines on outer surfaces in climbers; male flowers borne along opposite sides of rachillae; female flowers borne in pairs with a sterile male flower, along opposite sides of rachillae. Fruits mostly small, variously shaped and colored, usually 1-seeded, sometimes pedicellate, always covered with overlapping scales, these sometimes with a groove down middle; endosperm homogeneous or ruminate; germination adjacent; eophylls bifid or pinnate.
Leaflets narrow to broad or rhomboid (praemorse in one Australian species), single-fold, arranged regularly or irregularly on either side of the rachis or variously clustered, fanned or paired, variously hairy, scaly or spiny
Rachis usually armed with reflexed hooks.
Seed with thick or thin, sweet or sour or very astringent sarcotesta and variously shaped hard diaspore; endosperm homogeneous or ruminate; embryo basal or lateral.
Stems very slender, only a few mm. in diameter to robust (15 cm. or more), in Africa moderate, 1–3 cm. in diameter, branching sympodially at the base
Leaf-sheaths tightly enclosing the stem, variously armed with spines and spiculae or unarmed, often covered with indumentum; often continued into an ocrea of varying length (in Africa conspicuous)
Female flower with calyx and corolla ± as in the ♂ flower; staminodes 6; ovary covered in vertical rows of reflexed scales and tipped with 3 stigmas; locules 3, incomplete, each with a single ovule, normally only 1 ovule developing
Mature leaf of two kinds, either terminating in a long barbed whip (cirrus) or without such a whip (African and some Asiatic species), species without a cirrus normally but not always bearing a similar barbed whip (flagellum), adnate to the leaf-sheath at the base, equivalent to a modified sterile inflorescence.
Fruit variously shaped, tipped with the stigmatic remains, bearing persistent calyx and corolla basally, and covered in vertical rows of reflexed scales
Petiole prominent or absent, variously armed with spines and hooks.
In ♀ inflorescence flowers borne in pairs, a sterile ♂ (acolyte) together with a fertile ♀ and 2 bracteoles (‘involucrophore’ and ‘involucre’)
Male flower symmetrical; calyx tubular, 3-lobed; corolla 3-lobed, divisions almost reaching the base; stamens 6, epipetalous, with free filaments; pistillode minute or absent. Sterile ♂ flower as the fertile ♂ but anthers empty.
Bracts variously armed, tubular, tightly sheathing, very rarely splitting, sometimes with an expanded limb, never caducous, though rarely tattering and decaying before fruiting; prophyll usually 2-keeled and empty; other bracts on main axis subtending close to very distant partial inflorescences; partial inflorescences bearing bracts subtending rachillae; rachillae usually with approximate tubular bracts, each, except for the one or more basalmost, subtending a flower or flower group.
Solitary or clustering, acaulescent to high-climbing pleonanthic dioecious palms
In ♂ inflorescence flowers solitary, borne together with a bracteole (‘involucre’)