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..
Herbs, or shrubs, with alternate or opposite leaves, and perfect regular nearly symmetrical flowers. Stipules mostly small or none. Sepals 5, rarely 4, imbricated, persistent. Petals of the same number and alternate with the sepals, imbricated, generally contorted. Stamens of the same number, alternate with the petals; filaments monadelphous at the base; anthers versatile, 2-celled. Ovary 1, 2-5-celled, or by false septa 4-10-celled. Ovules anatropous. Styles 2-5. Fruit mainly capsular. Seeds 1-2 in each cavity, oily; endosperm little or none; embryo straight; cotyledons flat.
About 14 genera and about 160 species of wide geographic distribution.
Stigmas introrse and elongated; sepals glandless; petals mostly blue or red.
Stigmas terminal and capitate; sepals, at least the inner ones, with marginal glands; petals mostly