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biennial cinquefoil, biennial or Greene's cinquefoil, Greene's cinquefoil

Habit Plants scarcely to ± tufted.
Caudex branches

thick, not columnar, not sheathed with marcescent whole leaves.

Stems

ascending to erect, (1–)2–6(–8.5) dm, hairs at base not stiff, not tubercle-based, glands sparse to abundant, conspicuous (to 1 mm, septate).

ascending to erect, (0.3–)0.8–2.5(–4.5) dm, lengths (2–)3–5 times basal leaves.

Leaves

ternate, (2–)4–12(–25) cm;

petiole (1–)2–8(–20) cm, long hairs sparse to common, spreading to ascending, 0.5–1.5(–3) mm, weak, crisped hairs usually absent, glands sparse to abundant, conspicuous (to 1 mm, septate);

leaflets 3, at tip of leaf axis, usually overlapping, largest ones mostly obovate or oval to nearly round, (0.5–)1–3(–4) × 0.3–3(–3.5) cm, distal 3/4 to ± whole margin evenly to unevenly incised 1/4–1/3(–1/2) to midvein, teeth 3–8(–13) per side, surfaces sparsely to moderately hairy, rarely glabrate, glands sparse to abundant at least abaxially.

Basal leaves

1.5–12(–20) cm;

petiole 1–7(–15) cm, long hairs sparse to abundant, spreading to ± ascending, rarely loosely appressed, 1–2(–2.5) mm, usually stiff, sometimes weak (subsp. chamissonis), verrucose, short and/or crisped hairs absent or sparse to abundant, cottony hairs absent, glands absent or sparse;

leaflets separate to ± overlapping, central obovate, 1–3.5(–4.5) × 0.5–2(–3) cm, usually petiolulate, petiolule to 5 mm, base cuneate, margins slightly revolute, distal ± 3/4 incised ± 1/2 to midvein, teeth (2–)3–4(–6) per side, ± approximate to distant, surfaces dissimilar, often strongly so, abaxial white to gray, long hairs 0.5–1.8 mm, cottony-crisped hairs ± dense, adaxial green, sometimes grayish green, long hairs sparse to abundant, short-crisped hairs sparse to abundant.

Cauline leaves

(0–)1–2.

Inflorescence(s)

(10–)20–70+-flowered.

1–7(–15)-flowered.

Pedicels

0.2–1(–2) cm.

1.5–5 cm in flower, to 6(–10) cm in fruit.

Flowers

epicalyx bractlets narrowly oblanceolate to narrowly obovate or elliptic, (1.5–)2–3.5(–4.5) × 0.5–1.5(–2) mm;

hypanthium (2–)3–4(–5.5) mm diam.;

sepals (2–)3–5 mm, apex broadly acute to obtuse;

petals pale yellow to yellow, broadly oblanceolate to obovate, (1–)2–2.7 × 1.5 mm;

stamens 10 or 15, filaments 0.5–1.2 mm, anthers 0.2–0.3 mm;

carpels 40–100, styles 0.5–0.7 mm.

epicalyx bractlets linear-lanceolate to lanceolate-elliptic, 2–5(–7) × 0.4–1.2(–1.5) mm, 1/4–1/2 as wide as sepals, margins usually flat, red glands absent or sparse and inconspicuous;

hypanthium 3–5 mm diam.;

sepals 3–6(–8) mm, apex acute;

petals 4–7(–10) × 4–7(–9) mm, ± longer than sepals;

filaments 0.8–1 mm, anthers 0.4 mm;

carpels 28–40, apical hairs absent, styles conic-columnar, strongly papillate-swollen in proximal 1/5–1/3, 1–1.5 mm.

Achenes

whitish or pale yellowish, 0.5–0.9 mm, smooth, without a corky protuberance.

1.1 mm.

Potentilla biennis

Potentilla arenosa

Phenology Flowering summer.
Habitat Moist meadows, stream banks, ditches, seepages
Elevation 400–3100 m (1300–10200 ft)
Distribution
from FNA
AK; AZ; CA; CO; ID; MT; ND; NM; NV; OR; UT; WA; WY; AB; BC; SK; YT
[WildflowerSearch map]
[BONAP county map]
from FNA
AK; AB; BC; MB; NT; NU; QC; SK; YT; Eurasia
[BONAP county map]
Discussion

Potentilla biennis may be recognized by its septate hairs with a round, terminal gland, which dominate the vestiture especially at the base of the plant. Stems are more commonly erect and leaflets rounder than those of P. rivalis. The species is most common along the eastern side of the Sierra Nevada of California, across the Intermountain Region to the Rocky Mountains. All specimens seen by the authors from Baja California, Mexico, which were previously referred to P. biennis are now assigned to P. rivalis.

J. Soják (1996) lectotypified Potentilla millegrana Engelmann ex Lehmann upon a collection of P. rivalis, thus preventing P. biennis from being a later taxonomic synonym.

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

Subspecies 2 (2 in the flora).

The name Potentilla arenosa is now used for most arctic and subarctic plants previously treated as P. hookeriana or P. nivea subsp. hookeriana (Lehmann) Hiitonen. As noted by J. Soják (1986), the type of P. hookeriana has quinate leaves; that name is now restricted to a Rocky Mountain species in sect. Rubricaules. The arctic and subarctic material was briefly (1989–1999) called P. nivea, as discussed under that species. Because the type of P. nivea var. arenosa and other northern Asian specimens correspond closely to the North American plants, the name P. arenosa is assigned here.

The two subspecies differ only in one character, the petiole hairs, but are largely allopatric. Subspecies arenosa occurs in western and northern Greenland, northern North America (very northern in the east), and northern Asia (and perhaps northeasternmost European Russia); subsp. chamissonis occurs in southern Greenland, northeastern North America (more southern than subsp. arenosa), and northern Europe at least east to the Urals.

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

Key
1. Petioles with common to abundant short and/or stiff crisped hairs in addition to long verrucose hairs.
subsp. arenosa
1. Petioles with sparse or no short and/or soft crisped hairs in addition to long verrucose hairs.
subsp. chamissonis
Source FNA vol. 9, p. 140. FNA vol. 9, p. 200.
Parent taxa Rosaceae > subfam. Rosoideae > tribe Potentilleae > Potentilla > sect. Rivales Rosaceae > subfam. Rosoideae > tribe Potentilleae > Potentilla > sect. Niveae
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. 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. nana, 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
P. albiflora, P. ambigens, P. anachoretica, P. angelliae, P. anglica, P. anserina, 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. nana, 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. arenosa subsp. arenosa, P. arenosa subsp. chamissonis
Synonyms P. nivea var. arenosa
Name authority Greene: Fl. Francisc., 65. (1891) (Turczaninow) Juzepczuk: in V. L. Komarov et al., Fl. URSS 10: 137. (1941)
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