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..
Succulent herbs, with alternate thin, simple dentate petioled leaves and showy very irregular axillary somewhat clustered flowers. Sepals 3, the 2 lateral ones small, green, nerved, the posterior one large, petaloid, saccate, spurred. Petals 5, or 3 with 2 of them 2-cleft into dissimilar lobes. Stamens 5, short; filaments appendaged by scales on their inner side and more or less united; anthers coherent or connivent. Ovary oblong, 5-celled; style very short, or none; stigma 5-toothed or 5-lobed; ovules several in each cell. Fruit in the following genus an oblong or linear capsule, elastically dehiscent into 5 spirally coiled valves, expelling the oblong ridged seeds. Endosperm none; embryo nearly straight; cotyledons flat. Later flowers small, cleistogamous, apetalous.
About 220 species, mostly natives of tropical Asia. The family consists of the following genus and the monotypic Asiatic Hydrocera, differing from Impatiens in its indehiscent 4-5-seeded berry. In our first edition it was placed at the end of the order Sapindales, but is here grouped in the Geraniales.