Geum rossii(synonym of Geum rossii var. depressum) |
Rosaceae subfam. rosoideae |
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Ross' avens |
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Habit | Plants subscapose. | Herbs, shrubs, or subshrubs. |
Stems | 4–28 cm, glabrous or downy, hairs to 1 mm, sometimes septate-glandular. |
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Leaves | basal 3–13 cm, blade pinnate to interruptedly pinnate, major leaflets 13–26, alternating with 0–14 minor ones, terminal leaflet slightly larger than major laterals; cauline 0.7–2 cm, stipules adnate to leaf, indistinguishable from pair of lobes, blade bractlike, not resembling basal, alternate, simple, pinnatifid to 3-fid. |
alternate, rarely opposite, pinnately compound, sometimes simple or palmately compound; stipules present, rarely absent. |
Inflorescences | 1–3(–4)-flowered. |
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Pedicels | woolly, sometimes glandular. |
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Flowers | erect; epicalyx bractlets 1.5–7 mm; hypanthium green, slightly purple-tinged to strongly purple; sepals erect to erect-spreading, 3–10 mm; petals spreading, yellow, obovate to nearly orbiculate, 5–12(–17) mm, longer than sepals, apex broadly rounded to irregularly emarginate. |
torus usually enlarged, sometimes small or absent; carpels 1–260(–450), distinct, free, styles distinct, rarely connate (Roseae); ovules 1(or 2), collateral (Rubeae) or superposed (Fallugia, Filipendula). |
Fruiting tori | sessile, glabrous. |
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Fruiting styles | wholly persistent, not geniculate-jointed, 2–5(–10) mm, apex not hooked, glabrous throughout or pilose only at base. |
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Fruits | achenes or aggregated achenes sometimes with fleshy, urn-shaped hypanthium or enlarged torus, sometimes aggregated drupelets; styles persistent or deciduous, not elongate (elongate but not plumose in Geum). |
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x | = 7(8). |
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2n | = 56. |
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Geum rossii |
Rosaceae subfam. rosoideae |
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Phenology | Flowering summer. | |
Habitat | Alpine and arctic tundra, rocky slopes, often in gravelly or peaty soil | |
Elevation | 0–4000 m (0–13100 ft) | |
Distribution |
AK; AZ; CO; ID; MT; NM; NV; OR; UT; WA; WY; BC; NT; NU; YT; Greenland; e Asia (Russian Far East) |
North America; Mexico; Central America; South America; West Indies; Bermuda; Eurasia; Africa; Atlantic Islands; Indian Ocean Islands; Pacific Islands; Australia |
Discussion | The variability accommodated here in Geum rossii was distributed by earlier monographers such as P. A. Rydberg (1913b) and F. Bolle (1933) among a half dozen species. W. Gajewski (1957) reduced them to two species, G. rossii and G. turbinatum; most recent taxonomists have recognized the two taxa as subspecies or varieties of a single species. The large geographic discontinuity between the Rocky Mountain and arctic ranges makes it easy for those wishing to follow this tradition. No one morphologic character or combination of characters neatly separates the arctic plants from those of the Rockies. Where their ranges overlap in Alaska, Geum rossii hybridizes with G. calthifolium to form sterile plants known as G. ×macranthum (Kearney ex Rydberg) B. Boivin; see discussion under 4. G. schofieldii. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Variation in the number of genera in subfam. Rosoideae is due to differences in generic delimitation between D. Potter et al. (2007) and the authors of some Potentilleae genera. Cyanogenic glycosides and sorbitol are absent in the subfamily. Tribes 6, genera 28–35, species ca. 1600 (6 tribes, 26 genera, 302 species, including 1 hybrid, in the flora) (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Source | FNA vol. 9, p. 63. | FNA vol. 9, p. 23. |
Parent taxa | ||
Sibling taxa | ||
Subordinate taxa | ||
Synonyms | Sieversia rossii, Acomastylis rossii, G. rossii var. depressum, G. rossii var. turbinatum, G. turbinatum, S. gracilipes | |
Name authority | (R. Brown) Seringe: in A. P. de Candolle and A. L. P. P. de Candolle, Prodr. 2: 553. (1825) | Arnott: Botany, 107. (1832) |
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