This section is from the book "An Illustrated Flora Of The Northern United States, Canada And The British Possessions Vol1", 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..
Somewhat fleshy herbs, perennial by rootstocks. Leaves cauline, whorled, or sometimes solitary long-petioled ones are borne on the rootstock. Flowers terminal, solitary or umbelled, sessile or pedicelled, perfect. Perianth of 3 separate sepals and 3 separate petals. Stamens 6; anthers 2-celled. Ovary sessile, 3-celled; styles 3, stigmatic along the inner side; ovules several or numerous in each cavity. Fruit a globose or 3-lobed berry.
Three genera and about 25 species, natives of the north temperate zone.
Leaves in 2 (rarely 3) whorls; flowers umbelled.
Leaves in 1 whorl; flowers solitary.