Minuartia glabra (Michx.) Mattf.
Habitat: Open granitic ledges of mountains less than 1000 m tall. [Rocky summits and outcrops (non-forested, upland)]
Range: Local, New England and New York, south to the mountains of Georgia, North Carolina, and Tennessee.
Aids to Identification: Smooth sandwort is an erect, glabrous herb with small white flowers and sessile (stalkless) leaves. The flowers, borne in groups of 3-7 per stem, are composed of a circle of 5 petals, each only 4-6 mm long. Likewise, the leaves are quite small, the upper measuring only 8-30 mm in length. M. glabra looks very similar to M. groenlandica, a species normally found on the higher mountains of western and central Maine. M. groenlandica is smaller with a dense tuft of basal leaves, 3-7 flowered cymes, and petals 6-10 mm long.
Ecological characteristics: This species is typically found in Maine along rocky outcrops on the coast and inland.
Phenology: Flowers May - September.
Synonyms: Arenaria glabra Michx.; Arenaria groenlandica (Retz.) Spreng. var. glabra (Michx.) Fern.; Minuartia groenlandica (Retz.) Ostenf. ssp. glabra (Michx.) A. & D. Löve; Porsildia groenlandica (Retz.) A. & D. Löve ssp. glabra (Michx.) A. & D. Löve; Sabulina glabra (Michx.) Small.
Known Distribution in Maine: This rare plant has been documented from a total of 25 town(s) in the following county(ies): Cumberland, Hancock, Knox, Lincoln, Oxford, Penobscot, Sagadahoc, Somerset.
Reason(s) for rarity: At northern limit of range.
Conservation considerations: Some populations could be threatened by heavy recreational (hiking) use of its hilltop habitat, but the plant appears to cope well with moderate disturbance.