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, shrubs or trees, with alternate mostly compound, commonly 2-3-pinnate leaves, the stipules various, and small regular mostly perfect flowers in heads, spikes or racemes. Calyx 3-6-toothed, or 3-6-lobed, the teeth or lobes mostly valvate in the bud. Corolla of as many distinct or more or less united petals, also valvate. Stamens as many as the petals, or twice as many, or 00, distinct, or monadelphous. Ovary 1-celled; ovules several or numerous; style simple. Fruit a legume. Seeds without endosperm; cotyledons fleshy.
About 40 genera and 1500 species, mostly of tropical distribution, a few in the temperate zones. This, and the three following families, are often united under the name Lec-uminosae.
Stamens numeroust at least more than 10.
Filaments united below.
Stamenstonly as many as the petals, or twice as many.
Petals separate; pod smooth.
Pod separating into valves.
Pod leathery, indehiscent.
Petals united to about the middle; pod spiny.