Dryas hookeriana |
Dryas alaskensis |
|
---|---|---|
Hooker's mountain-avens, mountain avens, white dryas, White Mountain-avens |
alaskan mountain-avens |
|
Habit | Plants 1.5–9 cm. | Plants 2–18 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 obovate or oblong-elliptic to narrowly oblong, 4.5–39 × 2–19 mm, base usually cuneate, sometimes truncate or cordate, margins coarsely dentate to crenate, sinuses 45–60% to midvein, apex rounded to obtuse, surfaces smooth to rugose, plicate, midvein and lateral veins adaxially sunken into folds, abaxial sparsely hairy to tomentose, adaxial usually glabrous, sometimes sparsely hairy proximally on midvein, feathery hairs and stipitate glands absent. |
Peduncles | 10–30 mm. |
25–130 mm. |
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 lanceolate to narrowly elliptic, 5.5–9 × 1.5–2 mm; petals 8, spreading, usually white or cream, sometimes yellow, 9–14 × 5–11 mm; filaments glabrous. |
Achenes | 2.5–3 mm; styles 11–25 mm. |
2–3 mm; styles 12–27 mm. |
2n | = 18. |
= 18. |
Dryas hookeriana |
Dryas alaskensis |
|
Phenology | Flowering Jun–Aug. | Flowering Jun–Aug. |
Habitat | Alpine meadows, dry rocky slopes and ridges, alpine tundra | Solifluction soil, sand-gravel beaches, sandy lakeshores, old beach ridges, wet meadows, stream banks, dry rocky knolls, rocky heath, ericaceous tundra |
Elevation | 1500–3900 m (4900–12800 ft) | 100–1800 m (300–5900 ft) |
Distribution |
AK; CO; ID; MT; OR; UT; WA; WY; AB; BC; NT
|
AK; YT; e Asia (Russian Far East: Chukotka) |
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.) |
Dryas punctata Juzepczuk has been reported from North America as a synonym of D. octopetala var. octopetala (E. Hultén 1968); it is now considered to be confined to northeastern Europe and northern Asia (R. Elven et al., http://nhm2.uio.no/paf/). Hultén (1959b) reduced D. octopetala var. glabrata to the rank of forma and later to synonymy under D. alaskensis (Hultén 1968). (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Source | FNA vol. 9, p. 329. | FNA vol. 9, p. 329. |
Parent taxa | Rosaceae > subfam. Dryadoideae > tribe Dryadeae > Dryas | Rosaceae > subfam. Dryadoideae > tribe Dryadeae > Dryas |
Sibling taxa | ||
Synonyms | D. octopetala var. angustifolia, D. octopetala subsp. hookeriana, D. octopetala var. hookeriana | D. octopetala subsp. alaskensis, D. octopetala var. glabrata, D. punctata subsp. alaskensis |
Name authority | Juzepczuk: Izv. Glavn. Bot. Sada S.S.S.R. 28: 325. (1929) | A. E. Porsild: Canad. Field-Naturalist 61: 187, plate 1, figs. 3 – 5. (1948) |
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