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arctic cinquefoil, dwarf cinquefoil

Habit Perennials, tufted to cushion-forming or matted, rarely rosetted, not stoloniferous (except sometimes P. verna); taproots not fleshy-thickened; vestiture primarily of straight hairs, not differentiated into long and short, glands absent or sparse to abundant, sometimes red (P. hyparctica). Plants densely tufted; caudex branches short, slender to ± stout, diam. 0.5–1 cm, including old leaf bases.
Stems

usually ascending to erect, sometimes prostrate to decumbent or spreading, not flagelliform, not rooting at nodes (except P. verna), lateral to persistent basal rosettes, 0.1–2(–3) dm, lengths 1–3(–4) times basal leaves.

ascending to erect, 0.1–0.5(–0.7) dm, lengths 1–2 times basal leaves.

Leaves

basal sometimes 2-ranked;

cauline 0–2(–3);

primary leaves ternate or palmate, (0.5–)1–12(–20) cm;

petiole: long hairs absent or spreading to ascending, weak to ± stiff, glands usually absent or sparse, sometimes abundant;

leaflets 3–7, at tip of leaf axis, overlapping or not, broadly oblanceolate or obtriangular to flabellate, margins flat to revolute, distal 1/4–3/4+ evenly to unevenly incised 1/4–1/2 to midvein, sometimes 3–5-lobed 1/2–3/4 to midvein as well, primary teeth (1–)2–5(–7) per side or per lobe, surfaces ± similar, abaxial pale to dark green, rarely grayish, brownish, or reddish, cottony hairs absent, adaxial green to dark green, rarely brownish or reddish, sometimes ± glaucous (P. grayi), long hairs (if present) soft to weak, sometimes stiff.

Basal leaves

not in ranks, ternate, 1–5 cm;

stipules: apex acute;

petiole 0.5–3.5 cm, long hairs sparse to abundant, ascending to spreading, 0.5–2 mm, ± soft, glands sparse to common;

leaflets 3, central obovate, 0.5–2 × 0.5–1 cm, petiolule 0–1 mm, margins revolute, not lobed, distal 1/2–2/3 evenly incised ± 1/2 to midvein, teeth 3–4(–6) per side, surfaces ± similar, green (paler abaxially), hairs sparse to abundant, 0.8–1.2 mm, glands sparse to common.

Inflorescences

1–6(–12)-flowered, ± cymose, ± to very open, or solitary flowers.

1(–2)-flowered.

Pedicels

usually straight in fruit (often recurved in P. verna), (0–)0.2–3(–9) cm, proximal usually not much longer than distal (sometimes longer in fruit).

straight, 0.2–1.5 cm in flower, to 5 cm in fruit.

Flowers

5-merous;

hypanthium 2–7 mm diam.;

petals pale to dark yellow, mostly ± obcordate (to orbiculate in P. elegans), (2–)3–10(–12) mm, usually longer than sepals, apex usually ± retuse;

stamens ca. 20;

styles subapical, columnar, filiform, or tapered, not, scarcely, or ± papillate-swollen in proximal 1/5–1/2, 0.8–2.5 mm.

epicalyx bractlets oblong or ovate, 2.5–5 × 1.5–3.5 mm, margins revolute;

hypanthium 3–3.5 mm diam.;

sepals 2.5–5 mm, apex ± acute;

petals pale yellow, 4–8 × 4–6 mm;

filaments 1.2–2 mm, anthers 0.3–0.4 mm;

carpels 40–50, styles ± columnar, not or scarcely papillate-swollen proximally, 0.8–1.2 mm.

Achenes

± smooth.

1.4–1.6 mm.

Potentilla sect. Aureae

Potentilla nana

Phenology Flowering summer.
Habitat Alpine and coastal Dryas-Salix-Empetrum heaths, gravelly slopes, ridge crests, fellfields, scree and talus
Elevation 100–1100 m (300–3600 ft)
Distribution
North America; Eurasia [Reportedly introduced in s Australia]
from FNA
AK; BC
[WildflowerSearch map]
Discussion

Species ca. 30 (10 in the flora).

The circumscription of sect. Aureae used here largely follows that of B. C. Johnston (1985), except that Potentilla sierrae-blancae is placed in sect. Concinnae and P. rubella and P. stipularis are in sect. Chrysanthae. Other treatments (for example, P. A. Rydberg 1908d; T. Wolf 1908) split the species included here in two groups and/or recombine them with species in other sections, notably sect. Ranunculoides (Th. Wolf) Juzepczuk.

Since Potentilla glaucophylla (sect. Graciles) and P. cottamii (sect. Subviscosae) are sometimes identified as members of sect. Aureae, they are included herein and key out in the third and twelfth couplets, respectively.

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

Potentilla nana has most often been considered a race of P. hyparctica or as the priority name for P. hyparctica. As now defined, P. nana occurs in an arc across southern Alaska, from the Aleutian and Pribilof islands to the Alaskan panhandle and adjacent British Columbia. T. Wolf (1908) treated it as a dwarf form of P. fragiformis; J. Soják (1996) interpreted P. nana as a hybrid species originating from cross(es) between P. fragiformis and P. hyparctica. Although the hybrid hypothesis has morphologic support, P. nana has a unique combination of morphologic features and has a distinct range from both P. fragiformis and P. hyparctica. The species are also ecologically segregated: P. nana is a coastal heath and gravel slope species, like P. hyparctica; P. fragiformis is strictly maritime coastal.

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

Key
1. Basal leaflets (3–)4–7
→ 2
1. Basal leaflets 3
→ 4
2. Basal leaves not in ranks; stems usually prostrate to decumbent, rarely weakly erect; caudex branches elongate and slender; pedicels often recurved; introduced.
P. verna
2. Basal leaves 2-ranked; stems ascending to erect; caudex branches usually short and stout, sometimes elongate and slender; pedicels straight; native
→ 3
3. Leaves glaucous, ± blue-green; styles 1.5–2.5(–3) mm; sepals: apex acute to short acuminate; w North America, Greenland.
P. glaucophylla (sect. Graciles)
3. Leaves not glaucous, green; styles 1–1.6 mm; sepals: apex broadly acute; ne Canada, Greenland.
P. crantzii
4. Central leaflets deeply 3–5-lobed (sinuses extending 1/2 to nearly to midvein), lobes unevenly incised 1/4–1/2 to midvein, teeth (1–)2–5 per lobe, glands sparse to abundant
→ 5
4. Central leaflets not or shallowly lobed (sinuses extending less than 1/2 to midvein), evenly or unevenly incised 1/4–1/2 to midvein, teeth 2–7 per side, glands absent or sparse to common
→ 6
5. Styles 1.3–2 mm; stems 0.3–2 dm; sepals 3–5 mm; nw California.
P. cristae
5. Styles 0.7–0.9 mm; stems 0.1–0.5 dm; sepals 2.2–2.5 mm; arctic.
P. elegans
6. Leaflet and epicalyx bractlet margins revolute; British Columbia, Alaska
→ 7
6. Leaflet and epicalyx bractlet margins flat, sometimes slightly or ± revolute; North America
→ 8
7. Petals 9–12 mm; caudex branches stout (diam. 1–2 cm, including old leaf-bases); filaments (2–)2.8–3.2 mm; styles 1.7–2 mm; 0–10 m.
P. fragiformis
7. Petals 4–8 mm; caudex branches slender to ± stout (diam. 0.5–1 cm, including old leaf-bases); filaments 1.2–2 mm; styles 0.8–1.2 mm; 100–1100 m.
P. nana
8. Styles 1–2.5 mm; filaments 1–3 mm
→ 9
8. Styles 0.6–1 mm; filaments 0.5–1(–1.5) mm
→ 11
9. Leaflet margins usually unevenly incised, teeth 3–7 per side, often secondarily toothed.
P. flabellifolia
9. Leaflet margins evenly incised, teeth (2–)3–4(–5) per side, not secondarily toothed
→ 10
10. Petioles: long hairs 1–2.5 mm; central leaflets: petiolules 0–1 mm; Greenland, ne Canada.
P. crantzii
10. Petioles: long hairs 0.5–1 mm; central leaflets: petiolules (1–)3–10 mm; California.
P. grayi
11. Epicalyx bractlets 3.5–7 mm; petals 4–9 mm.
P. hyparctica
11. Epicalyx bractlets (1.8–)2–2.5(–3) mm; petals 2–3 mm
→ 12
12. Epicalyx bractlets 1/2–3/4 as long as sepals; inflorescences 1–4-flowered; Great Basin.
P. cottamii (sect. Subviscosae)
12. Epicalyx bractlets ± equal to sepals; inflorescences 1(–2)-flowered; New England.
P. robbinsiana
Source FNA vol. 9, p. 188. Authors: Reidar Elven, Barbara Ertter, David F. Murray, James L. Reveal. FNA vol. 9, p. 192.
Parent taxa Rosaceae > subfam. Rosoideae > tribe Potentilleae > Potentilla Rosaceae > subfam. Rosoideae > tribe Potentilleae > Potentilla > sect. Aureae
Sibling taxa
P. albiflora, P. ambigens, P. anachoretica, P. angelliae, P. anglica, P. anserina, P. arenosa, P. argentea, P. arizonica, P. basaltica, P. bicrenata, P. biennis, P. biflora, P. bimundorum, P. bipinnatifida, P. brevifolia, P. breweri, P. bruceae, P. brunnescens, P. canadensis, P. concinna, P. cottamii, P. crantzii, P. crebridens, P. crinita, P. cristae, P. demotica, P. drummondii, P. effusa, P. elegans, P. erecta, P. flabellifolia, P. fragiformis, P. furcata, P. glaucophylla, P. gracilis, P. grayi, P. hickmanii, P. hippiana, P. holmgrenii, P. hookeriana, P. hyparctica, P. inclinata, P. intermedia, P. jepsonii, P. johnstonii, P. lasiodonta, P. litoralis, P. macounii, P. millefolia, P. modesta, P. morefieldii, P. multijuga, P. multisecta, P. newberryi, P. nivea, P. norvegica, P. ovina, P. paucijuga, P. pedersenii, P. pensylvanica, P. plattensis, P. pseudosericea, P. pulchella, P. pulcherrima, P. recta, P. reptans, P. rhyolitica, P. rimicola, P. rivalis, P. robbinsiana, P. rubella, P. rubricaulis, P. sanguinea, P. saximontana, P. sierrae-blancae, P. simplex, P. sterilis, P. stipularis, P. subgorodkovii, P. subjuga, P. subvahliana, P. subviscosa, P. supina, P. thurberi, P. thuringiaca, P. tikhomirovii, P. townsendii, P. uliginosa, P. uschakovii, P. vahliana, P. verna, P. versicolor, P. villosa, P. villosula, P. vulcanicola, P. wheeleri
Subordinate taxa
P. crantzii, P. cristae, P. elegans, P. flabellifolia, P. fragiformis, P. grayi, P. hyparctica, P. nana, P. robbinsiana, P. verna
Synonyms P. unranked Aureae, P. ser., P. section Frigidae P. emarginata subsp. nana
Name authority (Rydberg) Juzepczuk: in V. L. Komarov et al., Fl. URSS 10: 197. (1941) D. F. K. Schlechtendal: Ges. Naturf. Freunde Berlin Mag. Neuesten Entdeck. Gesammten Naturk. 7: 296. (1816)
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