Horkelia tenuiloba |
Horkelia fusca |
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Santa Rosa, Santa Rosa horkelia, Sonoma horkelia, thin-lobed, thin-lobed horkelia |
dusky, dusky horkelia, horkelia, pinewoods, pinewoods horkelia, pink pinwheels, tawny horkelia |
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Habit | Plants loosely matted, green. | |||||||||||||||||||||||||
Stems | ascending to erect, 1–4 dm, hairs ± spreading. |
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Basal leaves | weakly planar to ± cylindric, 5–15(–20) × 0.5–1.5 cm; stipules entire; leaflets 8–16(–20) per side, ± overlapping especially distally, cuneate to flabellate, 3–10 × 2–10 mm, 1/2 to nearly as wide as long, divided 1/2–3/4+ to midrib into 3–8 linear to narrowly oblanceolate or narrowly elliptic lobes, sparsely villous at least marginally, often with a tuft of hairs apically. |
(3–)4–20(–40) × (1–)1.5–4(–7) cm; leaflets narrowly cuneate to obovate to flabellate, 5–30(–35) × 2–20(–30) mm, 1/3 as wide to wider than long, divided into linear or oblanceolate to obovate teeth or lobes, sparsely to ± densely short-villous or hirsute, sometimes glabrate. |
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Cauline leaves | 2–5. |
1–5(or 6). |
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Inflorescences | open to congested, flowers arranged individually and in glomerules, these sometimes subcapitate. |
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Pedicels | 1–6 mm. |
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Flowers | 10 mm diam.; epicalyx bractlets narrowly to broadly lanceolate, 1–3 × 0.5–1 mm, slightly shorter than sepals, entire; hypanthium 1–1.2 × 2.5–4.5 mm, less than 1/2 as deep as wide, interior pilose; sepals spreading to reflexed, lanceolate, 3–5 mm; petals oblanceolate, 2.5–4.5 × 1.5 mm, apex emarginate; filaments (1–)1.5–2 × 0.5 mm, anthers 0.4–0.6 mm; carpels 10–25; styles 1.8–2.2 mm. |
5–12 mm diam.; epicalyx bractlets 1–3 mm, 1/2 length of to nearly equal to sepals; hypanthium 1–3 × 2–4 mm, 1/2 to nearly as deep as wide; sepals spreading to ± reflexed, narrowly to broadly lanceolate, (1.7–)2–4(–4.5) mm; petals 2–6(–6.5) mm; filaments 0.2–1.5 × (0.2–)0.4–0.6(–1) mm, anthers 0.4–0.6 mm; styles 0.9–1.5 mm. |
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Achenes | light brown, 1.5 mm, smooth or slightly rugose. |
brown. |
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2n | = 28. |
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Horkelia tenuiloba |
Horkelia fusca |
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Phenology | Flowering summer. | |||||||||||||||||||||||||
Habitat | Sandy soil, openings, in chaparral, oak woodlands | |||||||||||||||||||||||||
Elevation | 50–500 m (200–1600 ft) | |||||||||||||||||||||||||
Distribution |
CA
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CA; ID; NV; OR; WA; WY
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Discussion | Of conservation concern. Horkelia tenuiloba occurs on the western edges of the northern Coast Ranges in Marin, Mendocino, and Sonoma counties. Populations from San Luis Obispo formerly included in this species now are part of H. yadonii. A specimen (M. K. C[urran], July 5, 1885, UC) unequivocally of H. tenuiloba purportedly from San Luis Obispo is in all likelihood mislabeled with respect to locality. Horkelia tenuiloba is commonly associated with seral openings in chaparral and woodlands and might be dependent on periodic disturbance by fire. W. L. Jepson (1909–1943, vol. 2) used Potentilla stenoloba (1895) for the species encompassing the types of Horkelia tenuiloba and P. micheneri. The epithet micheneri (1893) has priority at species rank within Potentilla, since P. tenuiloba (Torrey) Greene is a later homonym of P. tenuiloba Jordan. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Varieties 7 (7 in the flora). Horkelia fusca represents the primary radiation of the genus beyond the California Floristic Province. Within California, H. fusca occurs in the Sierra Nevada and mountains of northern California, and it is the only representative of the genus extending beyond California and Oregon into Washington, Idaho, Nevada [with the possible exception of H. tridentata (10e. sect. Tridentatae) in Washoe County], and, questionably, Wyoming. As here circumscribed, Horkelia fusca is the most diverse, most widely distributed species in the genus, with significant additional work needed to fully elucidate its variation patterns. The treatment presented here differs from that of D. D. Keck (1938) and B. Ertter (1993d) in using the rank variety instead of subspecies, circumscribing var. capitata more narrowly, and transferring the application of var. pseudocapitata from what is here called var. brownii to the bulk of what had been subsp. capitata (Lindley) D. D. Keck (B. Ertter and J. L. Reveal 2007). There are two types of basal leaves in plants of Horkelia fusca. The ephemeral early-season leaves have leaflets that tend to be broadly cuneate-obovate, shallowly toothed, densely glandular but otherwise sparsely hairy, and deeply veined. The leaf features described below are drawn from the more persistent, mid season leaves that predominate at peak flowering and differ more strongly among varieties. Petals of first-formed flowers are often larger than average; end-of-season petals can be smaller than average. Although Montana is sometimes included in the range of Horkelia fusca, such references are based only on potential occurrence (W. E. Booth and J. C. Wright 1959). (Discussion copyrighted by Flora of North America; reprinted with permission.) |
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Key |
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Source | FNA vol. 9, p. 252. | FNA vol. 9, p. 259. | ||||||||||||||||||||||||
Parent taxa | Rosaceae > subfam. Rosoideae > tribe Potentilleae > Horkelia > sect. Horkelia | Rosaceae > subfam. Rosoideae > tribe Potentilleae > Horkelia > sect. Capitatae | ||||||||||||||||||||||||
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Synonyms | H. fusca var. tenuiloba, Potentilla micheneri, P. stenoloba | Potentilla douglasii | ||||||||||||||||||||||||
Name authority | (Torrey) A. Gray: Proc. Amer. Acad. Arts 6: 529. (1865) | Lindley: Edwards’s Bot. Reg. 23: plate 1997. (1837) | ||||||||||||||||||||||||
Web links |