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blunt-sepal starwort, obtuse starwort, Rocky Mountain chickweed, Rocky Mountain starwort

pygmy starwort, small starwort

Habit Plants perennial, creeping, often matted but not forming cushions, rhizomatous. Plants annual or perennial, forming mats, rhizomatous.
Stems

prostrate, branched, 4-sided, 3–23 cm, internodes equaling or longer than leaves, glabrous, rarely pilose.

creeping, much-branched, rooting at lower nodes, 4-angled, 5–30 cm, glabrous or sparsely pubescent on 2 sides.

Leaves

sessile or short-petiolate;

blade broadly ovate to elliptic, 0.2–1.2 cm × 0.9–7 mm, base round or cuneate, margins entire, apex acute, shiny, glabrous or ciliate near base.

sessile to subsessile;

blade elliptic to obovate, 0.3–1.5 cm × 1–6 mm, base cuneate to spatulate, margins entire, apex obtuse to ± acute, tip blunt, glabrous or pubescent at base and stem nodes.

Inflorescences

with flowers solitary, axillary;

bracts absent.

with flowers solitary, axillary in distal nodes;

bracts absent.

Pedicels

spreading, 3–12 mm, glabrous.

spreading, becoming reflexed in fruit, 2–10 mm, glandular-pubescent.

Flowers

1.5–2 mm diam.;

sepals 4–5, veins obscure, midrib sometimes apparent, ± ovate, 1.5–3.5 mm, margins narrow, scarious, apex ± obtuse, glabrous;

petals absent;

stamens 10 or fewer;

styles 3(–4), curled, shorter than 0.5 mm.

3–4 mm diam.;

sepals 4–5, herbaceous with midrib, ovate-lanceolate, 2.5–3 mm, margins convex, membranous, apex obtuse, glandular-pubescent;

petals 4–5, ca. 3 mm, equaling sepals;

stamens 4–5;

styles 3–4, ascending.

Capsules

green to pale straw colored, translucent, globose to broadly ovoid, 2.3–3.5 mm, 1.9–2 times as long as sepals, apex obtuse, opening by 6 valves;

carpophore absent.

broadly ovoid, ca. 4.5 mm, longer than sepals, apex obtuse, opening by 6–8 valves;

carpophore absent.

Seeds

grayish black, broadly elliptic, 0.5–0.7 mm diam., finely reticulate.

ca. 20, brown, round, ca. 1 mm diam., prominently papillate;

papillae obtuse, taller than broad.

2n

= 26, 52, ca. 65, ca. 78.

= 34.

Stellaria obtusa

Stellaria parva

Phenology Flowering late spring–summer. Flowering spring–fall.
Habitat Moist areas in woods, shaded edges of creeks, talus slopes Short grass in ditches and marshy areas
Elevation 300-3400 m (1000-11200 ft) less than 100 m (less than 300 ft)
Distribution
from FNA
CA; CO; ID; MT; OR; UT; WA; WY; AB; BC
[WildflowerSearch map]
[BONAP county map]
from FNA
LA; TX; South America (Argentina, Brazil, Paraguay) [Introduced in North America]
[BONAP county map]
Source FNA vol. 5, p. 110. FNA vol. 5, p. 111.
Parent taxa Caryophyllaceae > subfam. Alsinoideae > Stellaria Caryophyllaceae > subfam. Alsinoideae > Stellaria
Sibling taxa
S. alaskana, S. alsine, S. americana, S. borealis, S. calycantha, S. corei, S. crassifolia, S. crispa, S. cuspidata, S. dicranoides, S. fontinalis, S. graminea, S. holostea, S. humifusa, S. irrigua, S. littoralis, S. longifolia, S. longipes, S. media, S. neglecta, S. nitens, S. pallida, S. palustris, S. parva, S. porsildii, S. pubera, S. ruscifolia, S. umbellata
S. alaskana, S. alsine, S. americana, S. borealis, S. calycantha, S. corei, S. crassifolia, S. crispa, S. cuspidata, S. dicranoides, S. fontinalis, S. graminea, S. holostea, S. humifusa, S. irrigua, S. littoralis, S. longifolia, S. longipes, S. media, S. neglecta, S. nitens, S. obtusa, S. pallida, S. palustris, S. porsildii, S. pubera, S. ruscifolia, S. umbellata
Synonyms Alsine obtusa, Alsine viridula, Alsine washingtoniana, S. viridula, S. washingtoniana
Name authority Engelmann: Bot. Gaz. 7: 5. (1882) Pederson: Bot. Tidsskr. 57: 44, fig. 4. (1961)
Web links