Twining annual or perennial herbs, lacking tendrils or adventitious roots, dioecious (rarely monoecious). Stems with centrifixed hairs (at least when young). Leaves simple, usually palmately lobed, resin-dotted beneath; petioles often twining. Male inflorescences axillary, sometimes also terminal, paniculate, many-flowered. Flowers mostly 5-partite with free sepals; anthers as many as sepals, subsessile or with short, distinct filaments. Female inflorescences of pedunculate, compact, ovate to globose spikes or spike-like racemes, solitary or a few in axils or racemosely arranged; flowers single or paired, each one (or pair) overtopped by an accrescent bract; perianth vestigial; stigmas paired. Infructescence ovoid, cone-like with several rows of loosely overlapping, bracts, these often glandular.
Three species from Europe, Asia and N America, but precise distribution obscured by long history of cultivation. One species cultivated in Australia and weakly naturalised.