This section is from the book "An Illustrated Flora Of The Northern United States, Canada And The British Possessions Vol3", by Nathaniel Lord Britton, Addison Brown. Also available from Amazon: An Illustrated Flora of the Northern United States, Canada and the British Possessions. 3 Volume Set..
A glabrous perennial slender herb, with scaly or tuberiferous rootstocks, basal and opposite ternately compound leaves, and small green flowers in terminal capitate clusters. Calyx-tube hemispheric, adnate to the ovary, its limb 2-3-toothed. Corolla rotate, regular, 4-6-lobed. Stamens twice as many as the lobes of the corolla, inserted in pairs on its tube; filaments short; anthers peltate, 1-celled. Ovary 3-5-celled; style 3-5-parted; ovules 1 in each cavity, pendulous. Fruit a small drupe with 3-5-nutlets. Endosperm cartilaginous.
The family contains only the following monotypic genus of the north temperate zone.