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Dryas hookeriana

Hooker's mountain-avens, mountain avens, white dryas, White Mountain-avens

Habit Plants 1.5–9 cm. Shrubs or trees.
Leaves

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.

cauline;

stipules present.

Peduncles

10–30 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.

carpels 1–150, distinct, free, styles distinct;

ovule 1.

Fruits

achenes or aggregated achenes;

styles persistent, elongate, usually plumose.

Achenes

2.5–3 mm;

styles 11–25 mm.

2n

= 18.

Dryas hookeriana

Rosaceae subfam. dryadoideae

Phenology Flowering Jun–Aug.
Habitat Alpine meadows, dry rocky slopes and ridges, alpine tundra
Elevation 1500–3900 m (4900–12800 ft)
Distribution
from FNA
AK; CO; ID; MT; OR; UT; WA; WY; AB; BC; NT
[WildflowerSearch map]
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.)

The subfamily consists of a single tribe.

(Discussion copyrighted by Flora of North America; reprinted with permission.)

Source FNA vol. 9, p. 329. FNA vol. 9, p. 326. Author: Luc Brouillet.
Parent taxa Rosaceae > subfam. Dryadoideae > tribe Dryadeae > Dryas Rosaceae
Sibling taxa
D. ajanensis, D. alaskensis, D. drummondii, D. incisa, D. integrifolia, D. octopetala
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) Sweet: Brit. Fl. Gard., ser. 2, 1: sub plate 43. (1830)
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