Horkelia howellii |
Horkelia cuneata |
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Howell's horkelia, Klamath horkelia |
wedge leaf horkelia |
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Habit | Plants tufted to openly matted, ± green. | Plants matted or tufted, green to grayish. | ||||||||
Stems | ascending to erect, (0.9–)1.5–5 dm, hairs 1 mm proximally, glands absent or sparse distally. |
decumbent to erect, (1–)2–6(–7.5) dm, hairs ascending to appressed, sometimes spreading. |
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Basal leaves | ± cylindric to weakly planar, 5–15 × 0.5–1.8(–2.5) cm, usually villous to pilose at least marginally, often glabrescent; stipules deeply 2-lobed or pinnately divided into 3–5 linear to filiform lobes that often form a tangled mass; leaflets 10–15 per side, ± overlapping, elliptic to flabellate, (3–)4–10(–15) × 2–8 mm, 1/2 to as wide as long, divided 1/2–3/4 to midrib into (0–)2–4 elliptic to linear lobes 1–2 mm wide, these not restricted to apex. |
planar, (5–)10–30 × 1.5–4(–5) cm; stipules entire or basally lobed; leaflets 5–12 per side, separate to slightly overlapping, ± elliptic to obovate or oblanceolate, 5–25(–30) × 5–15(–25) mm, ± 1/2 to nearly as wide as long, divided less than 1/3 to midrib into (5–)10–15 oblanceolate to obovate teeth, sparsely pilose to glabrate or sericeous. |
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Cauline leaves | (2 or)3–5; stipules 5–12(–15) mm, entire to deeply 2–4-lobed or -toothed (usually on 1 side). |
1–3(–5). |
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Inflorescences | open, flowers arranged individually and/or in non-capitate glomerules. |
± open to congested, flowers arranged individually and/or in glomerules. |
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Pedicels | 1–6(–12) mm. |
1–30(–40) mm. |
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Flowers | 10 mm diam.; epicalyx bractlets linear-lanceolate, 1–3 × 0.5 mm, ± 2/3 length of sepals; hypanthium 1.1–1.5 × 2–3 mm, ± 1/2 to as deep as wide, interior glabrous; sepals spreading to reflexed, abaxially green to reddish or purplish, 2.5–4.5 mm; petals white to pink or red-veined, narrowly obcordate, 3–5 × 2–3 mm, apex truncate or emarginate; filaments 0.5–1.7 × 0.2–0.5 mm, anthers 0.4–0.6 mm; carpels 2–6; styles 1.5–2 mm. |
12–17 mm diam.; epicalyx bractlets lanceolate to ovate, 3–5 × 1.5–3 mm, 2/3–3/4 length of sepals, entire; hypanthium 1.5–2 × 4–7 mm, less than 1/2 as deep as wide, interior glabrous or pilose in a narrow ring; sepals ± reflexed to spreading, lanceolate, 4–6.5 mm; petals oblanceolate to narrowly obovate, 4–8 × 1.5–4 mm, apex obtuse to rounded; filaments 1–3 × 0.5–2 mm, anthers 0.7–1.1 mm; carpels (30–)40–60(–80); styles 2–3 mm. |
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Achenes | brown, 2–2.7 mm, smooth. |
brown, 1.5–1.8 mm, smooth or minutely rugose. |
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Horkelia howellii |
Horkelia cuneata |
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Phenology | Flowering summer. | |||||||||
Habitat | Chaparral, oak-conifer woodlands, mainly on serpentine soil | |||||||||
Elevation | 60–1200 m (200–3900 ft) | |||||||||
Distribution |
CA; OR
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CA
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Discussion | Of conservation concern. As noted above, Horkelia howellii comprises the bulk of what D. D. Keck (1938) and subsequent floras included in H. sericata, and the range of the latter is fully encompassed within that of the former. As here circumscribed, H. howellii occurs in northwestern California and southwestern Oregon. The handful of collections from Humboldt and Trinity counties, California, including the type of Potentilla laxiflora Drew, have leaves approaching H. daucifolia but the inflorescence of H. howellii; exact petal color is uncertain. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Varieties 3 (3 in the flora). As noted by D. D. Keck (1938) and B. Ertter (1997b), recognition of subunits within Horkelia cuneata is complicated by the abundance of intermediates, to the extent that a complete transition exists between the decumbent, densely hairy coastal extreme with a congested inflorescence, represented by var. sericea, and the erect, green-glandular interior extreme with an open inflorescence, represented by var. puberula. The traditional division into three infraspecific units is maintained here to emphasize the distinctiveness of the extremes, which would qualify as specifically distinct were they not ends of a continuum. The extremes are furthermore threatened by ongoing decimation of suitable habitats at the northern (San Francisco Bay Area) and southern (greater Los Angeles) ends of the species range. Determining the correct name of Horkelia cuneata if treated as a species of Potentilla is complicated. Potentilla cuneata (Lindley) Baillon ex Munz & I. M. Johnston (1925) and P. puberula Greene are both later homonyms, while P. multijuga Lehmann has been conserved with a conserved type to maintain established usage for an unrelated species of Potentilla (B. Ertter and J. L. Reveal 2008). J. T. Howell (1945) adopted P. lindleyi; however, as noted by R. F. Hoover (1966), P. kelloggii has priority at species rank by a matter of months. The latter is accordingly the correct name in Potentilla for H. cuneata. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
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Key |
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Source | FNA vol. 9, p. 265. | FNA vol. 9, p. 254. | ||||||||
Parent taxa | Rosaceae > subfam. Rosoideae > tribe Potentilleae > Horkelia > sect. Tridentatae | Rosaceae > subfam. Rosoideae > tribe Potentilleae > Horkelia > sect. Horkelia | ||||||||
Sibling taxa | ||||||||||
Subordinate taxa | ||||||||||
Synonyms | Potentilla howellii | Potentilla kelloggii var. cuneata, P. lindleyi | ||||||||
Name authority | (Greene) Rydberg: Bull. Torrey Bot. Club 25: 55. (1898) | Lindley: Edwards’s Bot. Reg. 23: sub plate 1997. (1837) | ||||||||
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