This section is from the book "An Illustrated Flora Of The Northern United States, Canada And The British Possessions Vol2", 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..
Shrubs, with aromatic bark, opposite entire short-petioled leaves, no stipules, and solitary large flowers on lateral leafy branches. Sepals and petals similar, imbricated in many series. Stamens 00, inserted on the receptacle, the inner sterile, short; anthers extrorse innate. Pistils ∞, nearly enclosed in the hollow receptacle; ovary 1-celled; ovules 1 or 2, anatropous, style filiform. Fruit accessory, consisting of the enlarged ovoid oblong or pyriform receptacle, to which the bases of petals, sepals and bracts are adnate, enclosing few to many smooth shining achenes. Seed erect; endosperm none; cotyledons foliaceous, convolute.
A family of 2 genera and about 6 species, natives of North America and eastern Asia, perhaps of closer affinity with the Rosaceae than where here inserted.