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 somewhat shrubby plants, mostly fleshy or succulent, with cymose or rarely solitary regular or symmetrical flowers. Stipules none. Calyx persistent, free from the ovary or ovaries, mostly 4-5-cleft or 4-5-parted. Petals equal in number to the calyx-lobes, distinct, or more or less united, usually persistent, rarely wanting. Stamens of the same number or twice as many as the petals; filaments filiform or subulate; anthers longitudinally dehiscent. Receptacle with a scale at the base of each carpel. Carpels equal in number to the sepals, distinct, or united below; styles subulate or filiform; ovules numerous, arranged in 2 rows along the ventral suture. Follicles membranous or coriaceous, 1-celled, dehiscent along the ventral suture. Seeds minute; endosperm fleshy; embryo terete; cotyledons short, obtuse.
About 30 genera and 600 species, of wide geographic distribution.
Stamens of the same number as the sepals; minute herbs.
Stamens twice as many as the sepals; succulent herbs.
Carpels erect; flowers often polygamous.
Carpels spreading; flowers perfect.