Dryas hookeriana |
Dryas integrifolia |
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Hooker's mountain-avens, mountain avens, white dryas, White Mountain-avens |
dryade a feuilles entières, entire-leaf mountain-avens, entire-leaf White Mountain-avens |
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Habit | Plants 1.5–9 cm. | Plants 3–14 cm. | ||||
Leaf | blades usually oblong-elliptic to lanceolate, sometimes ovate, 4–16(–25) × 1–6(–10) mm, base usually truncate or cordate, sometimes cuneate, margins strongly revolute to flat, coarsely dentate or serrate, sinuses 5–25(–30)% to midvein, apex acute to obtuse, surfaces smooth to slightly plicate, only midvein ± obscured adaxially within medial fold, abaxial tomentose to woolly (obscuring lateral veins), adaxial usually glabrous, sometimes sparsely hairy proximally on midvein, feathery hairs usually absent, rarely 1+ on midveins abaxially, midveins and petioles abaxially stipitate-glandular. |
blades linear to narrowly ovate or oblong to oval, 2–38 × 0.5–11 mm, base cordate to truncate or cuneate to rounded, margins usually entire or dentate to crenate, sometimes serrate in proximal 1/2, sinuses 5–15(–20)% to midvein, apex usually obtuse or acute, sometimes acuminate, surfaces usually smooth, sometimes rugulose, abaxial slightly hairy to tomentose, adaxial glabrous or sparsely hairy proximally on midvein, feathery hairs and stipitate glands absent. |
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Peduncles | 10–30 mm. |
10–150 mm. |
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Flowers | erect at flowering; sepals lanceolate to narrowly elliptic, 4–10 × 0.6–1.5 mm; petals 8, spreading, usually white or cream, sometimes yellow, 9–14 × 5–11 mm; filaments glabrous. |
erect at flowering; sepals linear-lanceolate, 3.5–9 × 1.5–2.5 mm; petals 8(–9), spreading, usually white or cream, sometimes yellow, 9–14 × 5–11 mm; filaments glabrous. |
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Achenes | 2.5–3 mm; styles 11–25 mm. |
0.8–3.5 mm; styles 8–29 mm. |
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2n | = 18. |
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Dryas hookeriana |
Dryas integrifolia |
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Phenology | Flowering Jun–Aug. | |||||
Habitat | Alpine meadows, dry rocky slopes and ridges, alpine tundra | |||||
Elevation | 1500–3900 m (4900–12800 ft) | |||||
Distribution |
AK; CO; ID; MT; OR; UT; WA; WY; AB; BC; NT
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AK; AB; BC; MB; NT; NU; ON; QC; YT; e Asia (Russian Far East)
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Discussion | In some states and provinces, the distribution of Dryas hookeriana is restricted to northwestern and central Colorado, southeastern and northernmost Idaho, western and central Montana, northeastern Utah (Uinta and Wasatch mountains), eastern Oregon and Washington, southwestern and central Wyoming, and western Northwest Territories. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Subspecies 2 (2 in the flora). Hybrid swarms between the two subspecies of Dryas integrifolia are common (E. Hultén 1968). (Discussion copyrighted by Flora of North America; reprinted with permission.) |
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Key |
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Source | FNA vol. 9, p. 329. | FNA vol. 9, p. 331. | ||||
Parent taxa | Rosaceae > subfam. Dryadoideae > tribe Dryadeae > Dryas | Rosaceae > subfam. Dryadoideae > tribe Dryadeae > Dryas | ||||
Sibling taxa | ||||||
Subordinate taxa | ||||||
Synonyms | D. octopetala var. angustifolia, D. octopetala subsp. hookeriana, D. octopetala var. hookeriana | |||||
Name authority | Juzepczuk: Izv. Glavn. Bot. Sada S.S.S.R. 28: 325. (1929) | Vahl: Skr. Naturhist.-Selsk. 4(2): 171. (1798) | ||||
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