Minuartia michauxii (Fenzl) Farw.
Habitat: Dry ledges, frequently on moderately high-pH substrate, infrequently on disturbed soil such as railroads and other dry, gravelly areas. [Rocky summits and outcrops (non-forested, upland)]
Range: Northern New Hampshire and southwestern Quebec to western Ontario, south to South Carolina, Kentucky, and Arkansas.
Aids to Identification: Michaux's sandwort is a low-growing, loosely tufted, diffuse perennial that is sometimes matted. Leaves are narrow and mostly linear, sepals are acute and prominently ribbed (separates this from M. groenlandica and M. glabra). Leaf blades have a midvein more prominent than the lateral veins (separates this from M. rubella with three equally prominent veins on the leaf). White flowers with five petals and sepals. Petals are oblong-obovate and about twice as long as the sepals.
Ecological characteristics: A plant of dry calcareous or magnesian (rarely siliceous) rock ledges, though it also occurs on dry, gravelly areas such as railroads. Michaux's Sandwort is present in all six New England states and is the most common sandwort found in New England, though it is rare in New Hampshire (S1/E), Massachusetts (S2/T), and Rhode Island (S1/E).
Phenology: Flowers May - July.
Synonyms: Maine and New England populations are represented by var michauxii. Synonyms include Arenaria michauxii (Fenzl) Hook. f.; Arenaria stricta Michx.; Minuopsis michauxii (Fenzl) W.A. Weber; Sabulina stricta (Michx.) Small. .