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Geum rossii var. depressum

Ross' avens

glacier avens

Habit Plants subscapose. Plants subscapose.
Stems

4–28 cm, glabrous or downy, hairs to 1 mm, sometimes septate-glandular.

2–30 cm, densely pilose, hairs 2–5 mm.

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.

basal 3–10 cm, blade pinnate-pinnatifid, leaflets/lobes 11–23, terminal leaflet slightly larger;

cauline 1.4–2.5 cm, stipules adnate to leaf, indistinguishable from lobes, blade bractlike, not resembling basal, alternate, simple, 3-fid.

Inflorescences

1–3(–4)-flowered.

1-flowered.

Pedicels

woolly, sometimes glandular.

densely pilose, eglandular.

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.

erect;

epicalyx bractlets 6–9 mm;

hypanthium green;

sepals spreading-erect, 7–14 mm;

petals 5–9, spreading, yellow, obovate, orbiculate, or ovate, 10–20 mm, longer than sepals, apex rounded to emarginate.

Fruiting tori

sessile, glabrous.

sessile, silky.

Fruiting styles

wholly persistent, not geniculate-jointed, 2–5(–10) mm, apex not hooked, glabrous throughout or pilose only at base.

wholly persistent, not geniculate-jointed, 18–30 mm, apex not hooked, pilose except distal 1–3 mm.

2n

= 56.

= 28.

Geum rossii

Geum glaciale

Phenology Flowering summer. Flowering early summer.
Habitat Alpine and arctic tundra, rocky slopes, often in gravelly or peaty soil Tundra, rocky slopes, heaths
Elevation 0–4000 m (0–13100 ft) 0–1400 m (0–4600 ft)
Distribution
from FNA
AK; AZ; CO; ID; MT; NM; NV; OR; UT; WA; WY; BC; NT; NU; YT; Greenland; e Asia (Russian Far East)
[BONAP county map]
from FNA
AK; NT; YT; Asia (n Russia)
[BONAP county map]
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.)

Flowers of Geum glaciale have from five to nine petals with seven being the most common. Other species of Geum nearly always have five petals, which is standard in most rosaceous genera. The sepals of G. glaciale are usually in two whorls for a total of about ten, and the bractlets are in two to three whorls. The exact number of epicalyx bractlets and sepals is made difficult to determine by the thick covering of hairs and because individual sepals and bractlets are sometimes deeply divided into two equal lobes.

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

Source FNA vol. 9, p. 63. FNA vol. 9, p. 62.
Parent taxa Rosaceae > subfam. Rosoideae > tribe Colurieae > Geum Rosaceae > subfam. Rosoideae > tribe Colurieae > Geum
Sibling taxa
G. aleppicum, G. calthifolium, G. canadense, G. geniculatum, G. glaciale, G. laciniatum, G. macrophyllum, G. peckii, G. radiatum, G. rivale, G. rossii, G. schofieldii, G. triflorum, G. urbanum, G. vernum, G. virginianum
G. aleppicum, G. calthifolium, G. canadense, G. geniculatum, G. laciniatum, G. macrophyllum, G. peckii, G. radiatum, G. rivale, G. rossii, G. schofieldii, G. triflorum, G. urbanum, G. vernum, G. virginianum
Synonyms Sieversia rossii, Acomastylis rossii, G. rossii var. depressum, G. rossii var. turbinatum, G. turbinatum, S. gracilipes Novosieversia glacialis, Sieversia glacialis
Name authority (R. Brown) Seringe: in A. P. de Candolle and A. L. P. P. de Candolle, Prodr. 2: 553. (1825) Adams ex Fischer: Mém. Soc. Imp. Naturalistes Moscou 2: 187, plate 11, fig. 20. (1809)
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