PLANT: Perennial, often cespitose; stems erect to decumbent, often much branched. LEAVES: mostly opposite, often alternate only in the inflorescence, simple, entire, linear to elliptic or lanceolate. INFLORESCENCE: terminal, the flowers 1-3. FLOWERS: pedicelled to sessile; calyx tube membranes ruptured in fruit, the lobes equal; corolla salverform, white to red, blue or purple; stamens unequally inserted on the tube; filaments short, usually equal in length, glabrous; anthers and style usually included. CAPSULE: ovoid to ellipsoid; seeds 1(2-3) per locule, usually not gelatinous when wet. 2n=14,28,42. NOTES: 70 spp.; N. Amer., 1 sp. in s S. Amer., 1 sp. in Siberia. (Greek: phlox = flame, from the brightly colored corollas). Wherry, E. 1955. The Genus Phlox. The Morris Arboretum. REFERENCES: Dieter H. Wilken and J. Mark Porter, 2005, Vascular Plants of Arizona: Polemoniaceae. CANOTIA 1: 1-37.
Cal tubular, scarcely accrescent, with scarious or hyaline intervals between the 5 green and more herbaceous ribs, ruptured by the developing capsule; corolla salverform, with slender tube and abruptly spreading lobes; filaments short, unequally placed in the cor-tube, the anthers included or some of them partly exserted; capsule 3-valved, with 1(-4) seeds per locule, the seeds unchanged when moistened; perennial (seldom annual) herbs or suffrutescent plants with entire, chiefly opposite lvs and handsome fls in terminal or terminal and axillary cymes that may be reduced to a single fl. 50-60, N. Amer. and n. Asia. Allied spp. often hybridize.
Gleason, Henry A. & Cronquist, Arthur J. 1991. Manual of vascular plants of northeastern United States and adjacent Canada. lxxv + 910 pp.