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..
Low tufted branching heath-like evergreen shrubs, with small sessile opposite, crowded, entire apparently veinless leaves, appressed, so that the branches appear 4-sided, and axillary solitary peduncled white or pink nodding flowers, on pedicels bracted at the base. Sepals 4 or 5, imbricated at least in the bud, not bracted at the base, persistent, or at length deciduous. Corolla campanulate, 4-5-lobed, the lobes recurved. Stamens 8-10, included; filaments subulate, glabrous, anthers in one plane, attached to the filaments near the apex, the sacs opening by large terminal pores and tipped with a recurved awn. Ovary 4-5-celled; ovules numerous; style slender, elongated; stigma simple. Capsule globose or ovoid, 4-5-valved, each valve 2-cleft at the apex. Seeds minute, not winged, numerous. [Name from Cassiope, mother of Andromeda.]
About 8 species, natives of the colder parts of the northern hemisphere, the following typical. Besides the following:, 2 others occur in the northwestern parts of North America.
Tufted, much-branched, 4'-12' high, the branches ascending or erect. Leaves thick, ovate or ovate-oblong, closely appressed, channeled on the back, concave or nearly flat on the inner (upper) surface, acute or the lower obtuse, usually puberulent when young, \"-\\" long; peduncles several or numerous, lateral, ascending or erect, slender, 5"-12" long; flowers 3"-4" broad; corolla 5-lobed; style slightly thickened below; capsule nearly globular, 1"-1 1/2" in in diameter.