About 45 species, mainly trees and shrubs from the northern temperate zone and rarely in South America. They are characterised by pairs of simple leaves and cymose umbels of small four to five-petalled flowers, in some species surrounded by large petal-like bracts. The berry-like fruits are single-seeded drupes.
The two species described are atypically non-woody herbaceous perennials spreading by rhizomes. They look good in a shady part of the rock garden, but can be invasive. Acid, moist but well drained soil is required and partial shade. Propagation by division when dormant, seed when ripe or as soon after as possible. Germination can take twelve to eighteen months.