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..
Perennial mostly acaulescent erect herbs, with basal tufted leaves (stem often climbing and leafy in Plumbago), and small perfect regular clustered flowers. Calyx inferior, gamosepalous, tubular or funnelform, 5-toothed, plaited at the sinuses, the tube 5-15-ribbed. Corolla of 5 hypogynous clawed segments, connate at the base or united into a tube, convolute or imbricated in the bud. Stamens 5, opposite the corolla-segments, hypogynous; filaments separate, or united at the base; anthers 2-celled, attached by their backs to the filaments, the sacs longitudinally dehiscent. Disk none. Ovary superior, I-celled; ovule solitary, anatropous, pendulous, the long funiculus arising from the base of the cavity; styles mostly 5, separate or united. Fruit a utricle or achene, enclosed by the calyx, rarely a dehiscent capsule. Seed solitary; testa membranous; endosperm mealy, or none; embryo straight; cotyledons entire.
About 10 genera and 350 species, of wide geographic distribution, mostly in saline situations.
Inflorescence cymose-pamculate: flowers in one-sided spikes.
Flowers in a dense terminal head.