Plants perennial herbs, prostrate or ascending to erect; nodes glabrous or minutely scabrous. Leaves opposite, linear to oblanceolate or elliptic; stipules absent; base sometimes attenutate into a ill-defined petiole; margins entire. Inflorescences axillary or terminal, laxly dichasial to densely umbellate cymes; peduncles present or not; bracts minute or obsolete. Flowers usually bisexual, rarely unisexual; sepals 5, free; petals/staminodes absent; stamens 5-15(-20), inserted below the gynoecium; filaments more or less lanceolate; ovaries superior, of (3-)5(-6) or 10-15 free carpels, each with a single ovlue and a style on the inner margin. Fruits clusters of 3-15 mericarps; mericarps more or less heterocarpic, some almost smooth with thin, almost membranous wals, others developing well-defined papillae, spines, and/or wings along the dorsal and venral sutures; seeds thikly lens-shaped, black, microscopically pitted.
The Gisekiaceae includes only one genus that has been placed in various families but with an anomalous set of characters that excludes it from all of them.