Peanut stitchwort

Arenaria rosei Maguire & Barneby, Leafl. W. Bot. 8: 56. 1956

Plants perennial, mat-forming. Taproots moderately stout, woody. Stems ascending to erect, green, 5-20 cm, glabrous except in inflorescence, glaucous, inter-nodes of stems 0.5-4 times as long as leaves (proximal leaves longer than internodes); rhizomes and trailing stems 5-20 cm. Leaves loosely overlapping proximally, ± evenly spaced, connate proximally, with tight, scarious sheath 0.2-0.6 mm; blade straight or outwardly curved, green, shallowly concave (dorsiventrally flattened, curved into trough), 1-veined abaxially, needlelike, 4-15 × 0.5-1.2 mm, ± flexuous, margins not thickened, scarious in proximal 1/ 5, smooth, apex green to purple, acute to obtuse, sometimes apiculate, navicular, dull, glabrous, glaucous; axillary leaves well developed among proximal cauline leaves. Inflorescences 12-25-flowered, open cymes; bracts subulate, herbaceous, margins scarious proximally. Pedicels 0.4-3 cm, often stipitate-glandular. Flowers: hypanthium disc-shaped; sepals obscurely 1-veined, narrowly ovate to lanceolate (herbaceous portion narrowly ovate to lanceolate), 2.5-4 mm, not enlarging in fruit, apex green to purple, acute to acuminate, not hooded, glabrous or very sparsely stipitate-glandular; petals oblanceolate to narrowly oblong-elliptic, 1.4-2.2 times as long as sepals, apex rounded, entire. Capsules sessile, ovoid, 3.5-4.3 mm, longer than sepals. Seeds reddish brown to brown, oblong-elliptic, compressed, 2.3-2.8 mm, tuberculate; tubercles low, rounded.

Flowering spring-summer. Open, serpentine slopes with scattered oak and Jeffrey pine; 700-1400 m; Calif.

Minuartia rosei, like M. decumbens and M. stolonifera, is restricted to serpentine soils of northwestern California. The three species are most closely related to the polymorphic M. nuttallii.