Potentilla versicolor |
Potentilla nivea |
|
---|---|---|
Steens Mountain cinquefoil, varying cinquefoil |
potentille des neiges, snow cinquefoil, snowy cinquefoil |
|
Habit | Plants rosetted to ± matted; taproots ± fleshy-thickened. | Plants ± tufted. |
Caudex branches | stout, not columnar, not sheathed with marcescent whole leaves. |
|
Stems | prostrate to ascending, (0.7–)1.5–2.5(–4) dm, lengths 2–4(–5) times basal leaves. |
ascending to erect, (0.3–)0.5–3(–4) dm, lengths 1.5–2.5(–4) times basal leaves. |
Basal leaves | pinnate with distal leaflets ± confluent, 4–12 × 1–2.5(–3.5) cm; petiole 1–3 cm, straight hairs absent (on early-season petioles) or sparse to common, spreading-ascending to loosely appressed, 1–2 mm, soft, cottony hairs usually absent, glands sparse; primary lateral leaflets 3–5 per side, on distal (1/3–)1/2–2/3 of leaf axis, overlapping, largest ones cuneate to flabellate, 0.5–1.5(–2) × 0.5–1.5 cm, distal 3/4 to whole margin unevenly incised 2/3 to completely to midvein (blade often medially split as well), ultimate teeth or segments 2–5(–8), ± oblanceolate, 3–11 × 1–3 mm, apical tufts to 1 mm, surfaces green to grayish green, not glaucous, straight hairs sparse to common (sparser adaxially), sometimes absent (except on margins), loosely appressed to ascending, 1–2 mm, soft, cottony hairs absent, glands sparse to common. |
(1–)3–10(–15) cm; petiole (0.5–)1–6(–10) cm, long hairs usually absent, sometimes sparse to common (less so than cottony hairs), ± appressed, 1–2 mm, soft, smooth, short-crisped hairs absent or obscured, cottony hairs abundant to dense sometimes sparse with age, glands absent, sparse, or obscured; leaflets overlapping, central obovate, 0.5–2(–4) × (0.2–)0.4–1.2(–2) cm, subsessile, base cuneate, margins slightly revolute, distal ± 3/4 incised (1/4–)1/3–1/2 to midvein, teeth (2–)3–5(–6) per side, ± approximate, surfaces dissimilar, often strongly so, abaxial ± white, long hairs 0.8–1.2 mm, cottony-crisped hairs dense, adaxial usually green, sometimes grayish green, long hairs sparse to abundant, short-crisped hairs sparse to common. |
Cauline leaves | 1–2(–3). |
0–1. |
Inflorescences | (1–)3–10-flowered, usually openly cymose. |
1–5(–7)-flowered. |
Pedicels | 1–3(–5) cm, straight to slightly recurved in fruit. |
1–4 cm in flower, to 5 cm in fruit. |
Flowers | epicalyx bractlets lanceolate to elliptic, rarely ovate, 2–5 × 1–2 mm, sometimes apically toothed; hypanthium 3–5 mm diam.; sepals 4–7 mm, apex acute; petals 4–7 × 3–5.5 mm; filaments (1–)1.5–2.5 mm, anthers 0.5–0.8 mm; carpels 10–25, styles 2 mm. |
epicalyx bractlets narrowly to broadly lanceolate or elliptic, (2–)4–7 × 0.6–1.7 mm, usually 1/4–1/2 as wide as sepals, margins flat, red glands usually absent, sometimes sparse, inconspicuous; hypanthium (2–)3–4 mm diam.; sepals (2.5–)4–8 mm, apex acute; petals (3–)4–8 × (3–)5–9 mm, slightly longer than sepals; filaments 0.9–1.2 mm, anthers 0.5 mm; carpels 20–40, apical hairs absent, styles narrowly columnar or columnar-tapered, strongly papillate-swollen at very base, rarely in proximal 1/5–1/3, 0.7–1.2 mm. |
Achenes | 1.5–1.8 mm, smooth to faintly rugose, not carunculate. |
1.1–1.5 mm. |
2n | = 56, 63; 28, 42, 49, 70 (Asia, Europe). |
|
Potentilla versicolor |
Potentilla nivea |
|
Phenology | Flowering summer. | Flowering summer. |
Habitat | Rocky, alpine meadows, seasonally moist slopes, near streams or snowmelt | Well-drained, exposed sites, ridge crests, coarse mineral soil, scree, usually on calcareous substrates |
Elevation | 2100–3200 m (6900–10500 ft) | 400–3800 m (1300–12500 ft) |
Distribution |
NV; OR
|
AK; AZ; CO; MT; NM; UT; WA; WY; AB; BC; MB; NL; NT; NU; QC; YT; Greenland; Eurasia
|
Discussion | Potentilla versicolor is most common on Steens Mountain in Harney County, Oregon. Collections are known from other mountain ranges in eastern Oregon (some possibly representing distinct taxa) and from near Island Lake in the Ruby Mountains of northeastern Nevada. The species often grows and, apparently, intergrades with P. breweri; it is usually distinct in its lack of cottony hairs. Petals, filaments, and styles tend to be somewhat shorter in P. versicolor than in P. breweri. Collections of P. versicolor have most often been identified as P. breweri, P. millefolia, or P. ovina. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Although now restricted to plants with exclusively (or at least predominantly) cottony hairs on the petioles, the name Potentilla nivea has a long history with an often wider application, sometimes including nearly all of sect. Niveae. As further confusion, J. Soják (1989) noted that the Linnaean type of P. nivea belonged to what is here treated as P. arenosa. Although historical usage of P. nivea has been re-established as a conserved name with a conserved type (B. Eriksen et al. 1999), from 1989 to 1999 the name P. nivea was applied to P. arenosa. During this period, P. prostrata subsp. floccosa was briefly adopted as the correct name for this species (for example, W. J. Cody 1996). Molecular evidence (B. Eriksen and M. H. Töpel 2006) indicates that populations of Potentilla nivea in the Atlantic regions, including Greenland and eastern Canada, differ from those in the Beringian regions of northwestern North America, suggesting expansion from separate Pleistocene refugia. A comparable pattern was noted by R. Elven and S. G. Aiken (2007) based on morphologic characters. The conserved type of P. nivea is from northern Sweden (Eriksen et al. 1999) and belongs to the Atlantic morphologic group. The variation within each region is large, and racial recognition would accordingly be premature. Plants from sites south of the continental glaciation, which were not included in the analysis by Eriksen and Töpel, deviate in having acuminate leaflet teeth and epicalyx bractlets and in being generally more slender. Epicalyx bractlets of some Washington plants are nearly as narrow as those of P. crebridens. Additional chromosome numbers have been reported for Potentilla nivea, but it is unknown whether these apply to this species, P. crebridens, some Asian relative, or hybrids. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Source | FNA vol. 9, p. 171. | FNA vol. 9, p. 198. |
Parent taxa | Rosaceae > subfam. Rosoideae > tribe Potentilleae > Potentilla > sect. Multijugae | Rosaceae > subfam. Rosoideae > tribe Potentilleae > Potentilla > sect. Niveae |
Sibling taxa | ||
Synonyms | P. prostrata subsp. floccosa | |
Name authority | Rydberg: in N. L. Britton et al., N. Amer. Fl. 22: 344. (1908) | Linnaeus: Sp. Pl. 1: 499. (1753) |
Web links |