The green links below add additional plants to the comparison table. Blue links lead to other Web sites.
enable glossary links

scarlet cinquefoil, Thurber's cinquefoil

Habit Herbs, shrubs, or subshrubs.
Stems

(2–)3–7(–10) dm.

Leaves

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

stipules present, rarely absent.

Basal leaves

palmate, (2–)4–15(–30) cm;

petiole (2–)3–10(–25) cm, long hairs sparse to common, spreading, 1–3.5 mm, weak, glands sparse to abundant, sometimes absent;

leaflets 5(–7), at tip of leaf axis, central one (1–)2–6(–8) × (0.5–)1–2.5(–4) cm, petiolules 0(–10) mm, distal 3/4 to whole margin incised 1/5–1/4 to midvein, teeth (4–)7–15(–19) per side (sometimes secondarily toothed), (1–)2–3(–5) mm, teeth apex acute to ± obtuse, surfaces slightly to strongly dissimilar, abaxial pale green to white, straight hairs sparse to abundant, often dense on veins, 0.5–3 mm, cottony hairs absent or sparse to dense, glands ± sparse or absent, sometimes obscured, adaxial green, straight hairs sparse to abundant, 0.2–1 mm, cottony hairs absent, glands ± sparse or absent.

Cauline leaves

stipules usually toothed, sometimes entire.

Inflorescences

(4–)10–35-flowered.

Pedicels

0.5–4 cm.

Flowers

epicalyx bractlets narrowly to broadly lanceolate-elliptic (rarely toothed or lobed), 4–9(–14) × (1–)1.5–2 mm;

sepals 4–10(–15) mm, apex acute to acuminate;

petals ± dark reddish throughout, (3.5–)6–10 × 6–10 mm;

filaments 1.5–3 mm, anthers 0.8–1 mm;

carpels 30–70, styles 2.5–3.5 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

1.5 mm, ± rugose.

x

= 7(8).

Potentilla thurberi

Rosaceae subfam. rosoideae

Distribution
from FNA
AZ; NM; nw Mexico
[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

Varieties 2 (2 in the flora).

The abaxially white-cottony leaflets of var. atrorubens usually make it easily distinguished from var. thurberi, which lacks cottony hairs and is usually less hairy in general. The two varieties sometimes occur together and intermediates between the extremes are common.

The degree of glandularity and the lengths of the central leaflets are greater in the southern populations of both varieties. The glands are less widely distributed on the plants northward and are fewer in northern Arizona and New Mexico. Leaflets are shorter and broader north of Graham County, Arizona, and Otero County, New Mexico.

(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.)

Key
1. Leaflets pale green abaxially, cottony hairs absent.
var. thurberi
1. Leaflets ± white to white abaxially, cottony hairs sparse to dense.
var. atrorubens
Source FNA vol. 9, p. 149. FNA vol. 9, p. 23. Author: Luc Brouillet.
Parent taxa Rosaceae > subfam. Rosoideae > tribe Potentilleae > Potentilla > sect. Rubrae 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. 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. 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. thurberi var. atrorubens, P. thurberi var. thurberi
Name authority A. Gray: Pl. Nov. Thurb., 318. (1854) Arnott: Botany, 107. (1832)
Web links