Potentilla sect. Potentilla |
Potentilla anglica |
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English cinquefoil, potentille d'angleterre, trailing cinquefoil, trailing tormentil, wood cinquefoil |
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Habit | Perennials, openly matted or ± tufted, often stoloniferous; taproots usually replaced by thick rootstocks; vestiture mostly of long hairs, glands absent or sparse, rarely common, sometimes reddish. | |||||||||||||||||
Stems | usually becoming ± prostrate, sometimes ascending to erect, often flagelliform, often rooting at nodes, lateral or central to persistent or ephemeral basal rosettes, 0.3–12+ dm, lengths (1–)2–10+ times basal leaves. |
soon becoming prostrate, ± flagelliform, usually openly branched, eventually rooting at some nodes, (0.3–)1.5–7+ dm. |
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Leaves | basal and cauline not in ranks; cauline (proximal to flowering and/or branching nodes) 0–3(–7); primary leaves ternate or palmate, 2–20(–30) cm; petiole: long hairs appressed to spreading, weak to stiff, glands absent or sparse, sometimes common; leaflets 3–5(–7), at tip of leaf axis, separate to slightly overlapping, obovate to narrowly elliptic, cuneate, or oblanceolate, margins flat or slightly revolute, distal 1/2–3/4 evenly incised 1/4–1/2 to midvein, teeth 2–13 per side, surfaces similar to ± dissimilar, abaxial usually green, sometimes silvery white, cottony hairs absent, adaxial green, not glaucous, long hairs usually ± stiff, sometimes weak or absent. |
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Basal leaves | ± persistent, ternate or palmate, 2–10(–12) cm; petiole 1–7(–8) cm, long hairs sparse to abundant, appressed, 0.5–1 mm, stiff, glands absent; leaflets 3–5, central ± obovate to cuneate, 1–3(–3.5) × 0.8–2(–2.5) cm, distal ± 1/2 of margin incised 1/4–1/3(–1/2) to midvein, teeth 2–4 per side, surfaces similar, green, sparsely to moderately hairy. |
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Cauline leaves | 2–3(–4) proximal to 1st flowering or branching node, usually well expanded at anthesis, usually ternate, 2–6(–10) cm; petiole 0.3–4(–8) cm; leaflets (3–)5, ± resembling or narrower than those of basal leaves, narrowly cuneate, 1–2(–3.5) × 0.8–2(–2.5) cm, apex rounded to obtuse. |
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Inflorescences | solitary flowers at stolon nodes or 3–30-flowered, cymose, open. |
solitary flowers at stolon nodes. |
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Pedicels | straight or slightly curved in fruit, (1–)2–12(–17) cm, proximal not longer than distal. |
(1–)3–10(–17) cm. |
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Flowers | 4–5(–10)-merous; hypanthium 1.5–5(–7) mm diam.; petals usually bright yellow, rarely cream, ± obcordate or obovate to round, (2–)4–9(–12) mm, usually longer than sepals, apex rounded to retuse; stamens 15–20; styles subapical, columnar-clavate to ± filiform, not papillate-swollen proximally, 0.6–1.5 mm. |
4(–5)-merous; epicalyx bractlets narrowly elliptic to oblong or ovate, 3–4(–7) × 1–1.5 mm, smaller than to slightly larger than sepals; hypanthium 2–4 mm diam.; sepals (3–)4–6 mm, apex broadly acute or acuminate; petals 6–9 × 5–9 mm, apex ± retuse; stamens 15–20, filaments 0.8–1.2 mm, anthers 0.8–1.2 mm; carpels 20–50, styles 0.9–1.5 mm. |
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Achenes | smooth or rugose. |
1–1.5(–1.8) mm, ± smooth. |
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Rootstocks | ± erect, stout to slender, 1–4 cm. |
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2n | = 28, 56 (Europe). |
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Potentilla sect. Potentilla |
Potentilla anglica |
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Phenology | Flowering May–Aug(–Nov). | |||||||||||||||||
Habitat | Moist flats and slopes, mainly on acidic soil | |||||||||||||||||
Elevation | 0–1200 m (0–3900 ft) | |||||||||||||||||
Distribution | e North America; Eurasia; n Africa; Atlantic Islands [Introduced in w North America, Mexico, West Indies, Bermuda, Central America, South America, c Africa (Ethiopia), Pacific Islands (New Zealand), Australia] |
CA; CO; ME; NY; OR; PA; UT; WA; BC; NL; NS; QC; SPM; Europe [Introduced in North America; introduced also in Atlantic Islands (Azores, Madeira), Pacific Islands (New Zealand), Australia]
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Discussion | Species 7 or 8 (5 in the flora). The species of sect. Potentilla comprise a monophyletic clade that includes Duchesnea, diverging basally to the species placed here in Horkelia, Horkeliella, and Ivesia (C. Dobeš and J. Paule 2010; M. H. Töpel et al. 2011). There are at least some morphological features by which this and other clades basal to the core Potentilla could be treated as separate genera. However, since the type of the genus (P. reptans) is in this section, doing so would require either a massive renaming of most Potentilla, or else conserving the type of the genus on a different species. If the latter course were taken, the species in this section would comprise Tormentilla. Among the distinctive features of sect. Potentilla are the high percentage of stoloniferous species (shared with Duchesnea), a tuberous rootstock in many species, and the presence of tetramerous-flowered species (P. anglica, P. erecta). The section is also distinctive in having an amphi-Atlantic distribution, with native species in both eastern North America and Europe. The native material has sometimes been treated as a single species, or with confused nomenclature (M. L. Fernald 1931), leading to much unreliability in older herbarium annotations. When leaves are palmate, the lateral leaflet pairs are usually more or less fused at the base, suggesting a ternate origin. Distal cauline leaves and inflorescence bracts are sometimes opposite. For comparison with other sections, counts of cauline leaves are restricted to nodes proximal to the first flowering stolon node, but descriptions of cauline leaves otherwise include all well-developed foliar structures at stolon nodes (until such time as these root and form new basal rosettes). (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Potentilla anglica apparently is a product of hybridization involving P. erecta and P. reptans (B. Matfield and J. R. Ellis 1972) that has become stabilized and distinct from both parents. In Europe, it forms back-cross hybrids with both P. erecta (P. ×suberecta Zimmeter) and P. reptans (P. ×mixta Nolte); these hybrids are not known from North America. A garden hybrid supposedly between P. anglica and P. nepalensis Hooker (known as P. ×tonguei Mallett) was found in Allegany State Park, New York, but this was likely cultivated rather than naturalized. Potentilla anglica probably was introduced even in Newfoundland (A. Kurtto et al. in J. Jalas et al. 1972+, vol. 13), contrary to the view expressed by M. L. Fernald (1950). The name Potentilla procumbens Sibthorp was previously used for this species; that is a superfluous and illegitimate name. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
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Key |
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Source | FNA vol. 9, p. 132. | FNA vol. 9, p. 135. | ||||||||||||||||
Parent taxa | ||||||||||||||||||
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Synonyms | P. section Tormentilla, section Tormentilla | |||||||||||||||||
Name authority | unknown | Laicharding: Veg. Europ. 1: 475. (1790) | ||||||||||||||||
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