18. Minuartia macrocarpa (Pursh) Ostenfeld, Meddel. Grønland. 37: 226. 1920.
Long-pod stitchwort, large-fruited sandwort
Arenaria macrocarpa Pursh, Fl. Amer. Sept. 1: 318. 1813; Alsinopsis macrocarpa (Pursh) A. Heller; Wierzbickia macrocarpa (Pursh) Reichenbach
Plants perennial, mat-forming. Taproots stout, woody. Stems erect to ascending, green, 3-10 cm, glabrous or sometimes stip-itate-glandular, internodes of flowering stems 1-5 times as long as leaves. Leaves tightly overlapping (vegetative), variably spaced (cauline), usually connate proximally, with tight, scarious to herbaceous sheath 1-1.5 mm; blade straight to outwardly curved, green, flat, 3-veined, often prominently so abaxially, linear to oblong or narrowly lanceolate, 4-14 × 0.5-2 mm, flexuous, margins thickened, ± coriaceous, ciliate, often densely so, apex green, rounded, navicular, shiny, glabrous or essentially so throughout or abaxially, sometimes pubescent adaxially, hairs resembling cilia; axillary leaves present among vegetative leaves. Inflorescences solitary flowers, terminal; bracts linear, herbaceous. Pedicels 0.4-1 cm, usually densely stipitate-glandular. Flowers: hypanthium cup-shaped; sepals prominently 3-veined proximally, lanceolate to oblong (herbaceous portion often purple, lanceolate to oblong), 4.5-6 mm, to 9 mm in fruit, apex often purple, rounded, hooded, stipitate-glandular; petals broadly obovate, 1.2-1.6 times as long as sepals, apex blunt or rounded, entire. Capsules narrowly ellipsoid, 10-18 mm, longer than sepals. Seeds red-brown to brown, orbiculate with radicle prominent and notch filled with papillae, somewhat compressed, 1-1.1 mm (excluding papillae), rounded-tuberculate, ringed with longitudinal, cylindrical, tan papillae 0.5-0.8 mm. 2n = 44 (Russia), 46, 48 (Russia).
Flowering spring-summer. Rocky, montane ridges, sandy slopes, well-drained alpine tundra and heathlands; 0-2200 m; B.C., N.W.T., Yukon; Alaska; Asia (Japan, Russian Far East, Siberia).
An amphi-Beringian species, Minaurtia macrocarpa is easily distinguished by having the largest capsules of any North American Minuartia.