Minuartia rossii
Minuartia obtusiloba
Ross' sandwort
alpine sandwort, alpine stitchwort, arctic sandwort, twin-flower sandwort
stout, woody.
stout, woody.
ascending to spreading, green or often purple, 1–3 cm, glabrous, internodes of flowering stems 0.2–1 times as long as leaves.
erect, green, 1–12 cm, trailing stems 2–20+ cm, stipitate-glandular, internodes of flowering stems 1–6 times as long as leaves.
overlapping, ± tightly (vegetative), ± evenly spaced proximally (cauline), connate-perfoliate proximally, with tight, herbaceous sheath 0.2–0.3 mm;
blade upwardly curved, green or often purple, keeled, prominently 1-veined abaxially, subulate, 3-angled, 1–4 × 0.5–0.7 mm, flexuous, margins rounded, herbaceous, smooth, apex green to purple, rounded, navicular, shiny, glabrous;
axillary leaves well developed.
tightly overlapping (vegetative), variably spaced (cauline), usually connate proximally, with tight, scarious to herbaceous sheath 0.3–1.5 mm;
blade straight to outwardly curved, green, 3-angled, 3-veined abaxially, midrib prominent, lateral veins weak in distal 1/3, needlelike to subulate, 1–8 × 0.4–1 mm, flexuous, margins not thickened, herbaceous, sometimes finely ciliate, apex green, rounded to acute, often apiculate, somewhat navicular, shiny, glabrous;
axillary leaves present among vegetative leaves.
solitary flowers, axillary or terminal (rarely present);
bracts absent.
solitary flowers, terminal, or occasionally in 2–3-flowered, open cymes;
bracts subulate, herbaceous.
0.1–2 cm, glabrous.
0.3–1.5 cm, stipitate-glandular.
hypanthium disc-shaped;
sepals 1-veined, oblong-ovate (herbaceous portion usually purple, oblong-ovate), 1.5–2.5 mm, not enlarging in fruit, apex often purple, obtuse to acuminate, navicular, not hooded, glabrous;
petals obovate to spatulate, 1.5–2 times as long as sepals, apex obtuse, entire.
hypanthium cup-shaped;
sepals prominently 3-veined proximally, narrowly ovate to oblong (herbaceous portion lanceolate to oblong), 2.9–6.5 mm, not enlarging in fruit, apex often purple, narrowly rounded, hooded;
petals ovate to spatulate, 1.2–2 times as long as sepals, apex rounded, entire.
on stipe ca. 0.1–0.2 mm, spheric, 1.5–2.5 mm, equaling sepals.
narrowly ellipsoid, 3.5–6 mm, equaling sepals.
brown, suborbiculate, compression unknown, ca. 0.6 mm, obscurely reticulate.
reddish tan, suborbiculate with radicle prolonged into beak, somewhat compressed, 0.6–0.7 mm, obscurely sculptured (50x).
= 58 (Russia), 60.
= 26, ca. 52, 78.
Minuartia rossii
Minuartia obtusiloba
Minuartia rossii is the northernmost member of the M. rossii complex (S. J. Wolf et al. 1979; B. Maguire 1958), a pulvinate species of moist arctic areas. While specimens occasionally have many flowers, some specimens have few if any, instead reproducing via small axillary fascicles of leaves or short shoots in the upper leaf axils (see also Ö. Nilsson 2001).
(Discussion copyrighted by Flora of North America; reprinted with permission.)
Minuartia obtusiloba, an amphi-Beringian species, sometimes forms hybrid swarms with M. arctica. Specimens labeled Arenaria sajanensis Willdenow ex Schlechtendal from western North America, sometimes referred to M. biflora (e.g., H. J. Scoggan 1978–1979, part 3), are likely to be M. obtusiloba.
(Discussion copyrighted by Flora of North America; reprinted with permission.)
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