Minuartia obtusiloba

(Rydberg) House

Amer. Midl. Naturalist 7: 132. 1921.

Common names: Twin-flower sandwort alpine stitchwort
Basionym: Alsinopsis obtusiloba Rydberg Bull. Torrey Bot. Club 33: 140. 1906,
Synonyms: Alsinopsis obtusiloba (Rydberg) Fernald Lidia obtusiloba (Rydberg) Á. Löve & D. Löve
Treatment appears in FNA Volume 5. Treatment on page 131. Mentioned on page 118, 119, 120, 121.

Plants perennial, cespitose to mat-forming. Taproots stout, woody. Stems erect, green, 1–12 cm, trailing stems 2–20+ cm, stipitate-glandular, internodes of flowering stems 1–6 times as long as leaves. Leaves 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. Inflorescences solitary flowers, terminal, or occasionally in 2–3-flowered, open cymes; bracts subulate, herbaceous. Pedicels 0.3–1.5 cm, stipitate-glandular. Flowers: 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. Capsules narrowly ellipsoid, 3.5–6 mm, equaling sepals. Seeds reddish tan, suborbiculate with radicle prolonged into beak, somewhat compressed, 0.6–0.7 mm, obscurely sculptured (50×). 2n = 26, ca. 52, 78.

Phenology: Flowering summer.
Habitat: Dwarf willow communities, fell-fields, snow beds in subalpine and alpine areas
Elevation: 0-4000 m


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Alta., B.C., N.W.T., Yukon, Alaska, Ariz., Calif., Colo., Idaho, Mont., Nev., N.Mex., Oreg., Utah, Wash., Wyo., Asia (Russian Far East).


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.

Selected References


Lower Taxa

... more about "Minuartia obtusiloba"
Richard K. Rabeler +, Ronald L. Hartman +  and Frederick H. Utech +
(Rydberg) House +
Alsinopsis obtusiloba +
Twin-flower sandwort +  and alpine stitchwort +
Alta. +, B.C. +, N.W.T. +, Yukon +, Alaska +, Ariz. +, Calif. +, Colo. +, Idaho +, Mont. +, Nev. +, N.Mex. +, Oreg. +, Utah +, Wash. +, Wyo. +  and Asia (Russian Far East). +
0-4000 m +
Dwarf willow communities, fell-fields, snow beds in subalpine and alpine areas +
Flowering summer. +
Amer. Midl. Naturalist +
Illustrated +
Alsinopsis obtusiloba +  and Lidia obtusiloba +
Minuartia obtusiloba +
Minuartia +
species +