Minuartia rossii
Minuartia macrantha
Ross' sandwort
House's stitchwort, large-flower sandwort
stout, woody.
occasionally filiform or often woody, somewhat thickened to moderately stout.
ascending to spreading, green or often purple, 1–3 cm, glabrous, internodes of flowering stems 0.2–1 times as long as leaves.
erect to procumbent, green, 2–15 cm, glabrous, internodes of all stems 0.3–1(–2) 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.
moderately to tightly overlapping (proximal cauline), variably spaced, progressively more so distally (distal cauline), connate proximally, with loose, scarious sheath 0.3–0.8 mm;
blade straight to slightly outcurved, green, flat, to 3-angled distally, 1–3-veined, midvein more prominent than 2 lateral veins, subulate to linear, 5–10 × 0.5–1.2 mm, flexuous, margins not thickened, scarious, smooth, apex green, rounded, thickened and navicular, shiny, glabrous;
axillary leaves present among proximal cauline leaves.
solitary flowers, axillary or terminal (rarely present);
bracts absent.
solitary flowers, terminal, or 2–5(–8)-flowered, open cymes;
bracts broadly subulate, herbaceous or scarious-margined proximally.
0.1–2 cm, glabrous.
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 disc-shaped;
sepals strongly 3-veined, ovate to lanceolate (herbaceous portion lanceolate), 3.5–5 mm, to 5.5 mm in fruit, apex green or purple in part, sharply acute to acuminate, not hooded, glabrous;
petals oblong to obovate, 0.7–1.8 times as long as sepals, apex rounded to blunt, entire.
on stipe ca. 0.1–0.2 mm, spheric, 1.5–2.5 mm, equaling sepals.
on stipe ca. 0.2 mm, broadly ovoid, 3–3.8 mm, shorter than sepals.
brown, suborbiculate, compression unknown, ca. 0.6 mm, obscurely reticulate.
black, suborbiculate with radicle prolonged to rounded beak, somewhat compressed, 0.7–1 mm, tuberculate;
tubercles low, rounded.
0.2–1.5 cm, glabrous.
= 58 (Russia), 60.
Minuartia rossii
Minuartia macrantha
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.)
B. Maguire (1958) segregated Minuartia filiorum (as Arenaria filiorum) from M. macrantha on the basis of habit (annual or at most a weak perennial), 3–7 flowers per inflorescence, and petals shorter than the sepals. Some populations may be distinguished using those features; the number of flowers per inflorescence is more variable than Maguire noted, and the seeds of the plants are identical with those of typical M. macrantha. We concur with W. A. Weber’s herbarium annotations that M. filiorum and M. macrantha are conspecific.
(Discussion copyrighted by Flora of North America; reprinted with permission.)
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