Mat-forming, 30-60cm across with flowering stems to 10cm high. Leaves linear to narrowly awl-shaped, up to 2cm or even 2.5cm long, finely ciliate and pilose. Flowers 1.3-2.5cm in diameter with tubes up to 2.1cm long, the petals obovate, entire or notched, purple to red or, less commonly violet-purple, lilac, pink or white, in loose clusters of three to six, spring to early summer, often with a few at intervals until autumn. North-eastern U.S.A. and adjacent Canada, on open gravelly and sandy slopes in rather poor acid soil.
P.s. australis has leaves 8-15mm long and notched-petalled flowers 1.5-1.7cm wide, in shades mainly of purple but also bluish or reddish, rarely pink and white. P.s. brittonii is like australis but is only lavender to white-flowered, often with an eye surrounded by short radiating violet lines. P. subulata is the most popular of the so-called moss phloxes. Many cultivars are available in a range of colours, some of hybrid origin with bifida (e.g. 'Millstream Jupiter' and 'Stellaria') or nivalis (e.g. 'Vivid') and probably other species including possibly douglasii or what passes under that name in cultivation.