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

Habit Herbs, shrubs, or subshrubs.
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).

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.

alternate, rarely opposite, pinnately compound, sometimes simple or palmately compound;

stipules present, rarely absent.

Inflorescences

(10–)20–70+-flowered.

Pedicels

0.2–1(–2) cm.

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.

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).

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).

Achenes

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

x

= 7(8).

Potentilla biennis

Rosaceae subfam. rosoideae

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]
North America; Mexico; Central America; South America; West Indies; Bermuda; Eurasia; Africa; Atlantic Islands; Indian Ocean Islands; Pacific Islands; Australia
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.)

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. 140. FNA vol. 9, p. 23. Author: Luc Brouillet.
Parent taxa Rosaceae > subfam. Rosoideae > tribe Potentilleae > Potentilla > sect. Rivales Rosaceae
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
Subordinate taxa
Name authority Greene: Fl. Francisc., 65. (1891) Arnott: Botany, 107. (1832)
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