Rhizome monopodial, with 2 vascular bundles in cortex. Erect stems absent or strongly abbreviated, with dense, persistent fibrous leaf bases. Leaves linear, usually leathery, with 3-7 parallel veins, margin irregularly minutely denticulate; sheaths with an auricle, ligulate. Spadix axillary, sessile, axis flattened, with a row of conspicuous flaplike projections (retinacula) on each side of axis. Plants dioecious; flowers unisexual, small. Anthers 2-celled. Female flowers consisting of 1 carpel, often with staminode; style short; stigmas 2, capillary. Fruit curved, with a short beak.

About five species: widely distributed along shores of the N Pacific Ocean; two species in China.