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..
Annual, biennial or perennial herbs, with watery sap, dissected alternate or basal leaves without stipules, and perfect, irregular flowers variously clustered. Sepals 2, small, scale-like. Petals 4, somewhat united, the 2 outer ones spreading above, one or both saccate or spurred at the base, the 2 inner smaller, narrower, thickened at the tips and united over the stigma. Stamens 6, diadelphous, hypo-gynous, in 2 sets of 3; anther of the middle ones 2-celled, of the lateral ones 1-celled. Carpels 2, united into a single pistil, the ovary 1-celled; stigma 2-lobed or 2-horned; ovules anatropous or amphitropous. Fruit a 2-valved several-seeded capsule, or 1-seeded and indehiscent. Seeds with a minute embryo in fleshy endosperm.
Five genera and about 170 species, natives of the north temperate zone and southern Africa. Each of the 2 outer petals spurred at the base.
Corolla deeply cordate at base; petals slightly coherent.
Corolla rounded or slightly cordate; petals permanently coherent, persistent.
One of the outer petals spurred at base.
Capsule 2-valved, few-several-seeded.
Fruit globose, indehiscent, 1-seeded.