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..
Annual or perennial, generally pubescent or hirsute herbs, with terminal dichotomous cymes of white flowers. Sepals 5, rarely 4. Petals of the same number, emarginate or bifid (rarely wanting). Stamens 10, rarely fewer. Styles equal in number to the sepals and opposite them, or in some species fewer. Capsule cylindric, I-celled, many-ovuled, often curved, dehiscent by 10, rarely 8, apical teeth. Seeds rough, more or less flattened, attached by their edges. [Greek, horny, referring to the horn-like capsule of many species.]
About 50 species, of wide geographic distribution, most abundant in the temperate zones. Type species: Cerastium arvcnse L.
Petals equalling the sepals, or shorter; annuals.
Pedicels not longer than the sepals; flowers glomerate.
Pedicels at length longer than the sepals; flowers cymose.
Leaves 2"-4" long; capsule nearly straight.
Leaves 4"-12" long; capsule curved upward.
Petals manifestly longer than the sepals (rarely wanting).
Annuals, viscid-pubescent; flowers 2"-3" broad.
Pedicels much longer than the calyx.
Pedicels shorter than or but little exceeding the calyx.
Perennials, glabrous or pubescent; flowers 6"-10" broad.
Styles always 5.
Leaves linear or lanceolate-oblong, mainly acute.
Leaves linear to linear-lanceolate; pod about half as long again as the calyx.
Leaves lanceolate to oblong-lanceolate; pod twice as long as the calyx.
Leaves oblong-ovate, obtuse.
Styles 3 (very rarely 4 or 5); leaves linear-oblong.
Cerastium viscosum L. Sp. Pl. 437. 1753. Cerastium glomeratum Thuill. Fl. Paris, Ed. 2, 226. 1824.
Annual, tufted, stems ascending or spreading, densely viscid-pubescent, 4'-12' long. Leaves ovate or obovate, or the lower spatulate, 4"-12" long, 3"-7" wide, obtuse; bracts small, herbaceous; flowers about 2"-3" broad, in glomerate cymes, becoming paniculate in fruit; pedicels shorter than or equalling the acute sepals; petals shorter than the calyx, 2-cleft.
In waste places and meadows, New Brunswick to Ontario, Florida, Arkansas and Mexico. Naturalized from Europe. Naturalized also in the West Indies, Central America, and on the Pacific Coast. April-July.