Stems slender, climbing, clustered or less often solitary, sometimes non-climbing or even short and subterranean. Leaves 13-30, pinnate, spiny; leaf sheaths closed in climbing species, open in non-climbing ones, covered with various hairs and spines, these scattered (rarely absent) to densely arranged, or arranged in rows, variously shaped and colored, rarely spines arranged in overlapping, interlocking rings forming ant chambers; ocreas present, obscure; knees present except in non-climbers; cirri present except in non-climbers; pinnae variously arranged and shaped. Plants dioecious, rarely semelparous. Inflorescences branched to 3 orders, male inflorescences more branched than female ones, both covered with overlapping bracts, these persistent, swollen, and split lengthwise to reveal rachillae, apices of all bracts included within prophyll, in other species bracts falling from elongating inflorescence, and only basal bract persistent; male flowers usually arranged distichously along rachillae; female flowers borne in pairs, each pair consisting of a female flower and a sterile male flower. Fruits variously shaped and colored, usually 1-seeded, covered with overlapping scales, usually borne on short stalks; endosperm ruminate; germination adjacent; eophylls pinnate, rarely palmate.

About 100 species: from NE India through SE Asia to just reaching New Guinea; one species in China.