Horkelia howellii |
Horkelia hispidula |
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Howell's horkelia, Klamath horkelia |
White Mountain horkelia, White Mountains. horkelia |
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Habit | Plants tufted to openly matted, ± green. | Plants 0.7–3 dm diam. |
Stems | ascending to erect, (0.9–)1.5–5 dm, hairs 1 mm proximally, glands absent or sparse distally. |
ascending to erect, 1–2.5 dm. |
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. |
3–10 × 0.4–0.8 cm; leaflets (6–)10–14 per side, ± overlapping at least distally, cuneate to flabellate, 2.5–4(–6) mm, divided 3/4+ to midrib into 3–6 oblanceolate to obovate lobes, hispid. |
Cauline leaves | (2 or)3–5; stipules 5–12(–15) mm, entire to deeply 2–4-lobed or -toothed (usually on 1 side). |
3–7. |
Inflorescences | open, flowers arranged individually and/or in non-capitate glomerules. |
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Pedicels | 1–6(–12) mm. |
2–8(–12) mm. |
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. |
3–15, 10 mm diam.; epicalyx bractlets linear to lanceolate, 1.5–3 × 0.2–0.5 mm, ± 2/3 length of sepals; hypanthium 1.8–3 × 3–4 mm, ± 1/2 as deep as wide, interior sparsely pilose; sepals reflexed, broadly lanceolate, 2.5–4(–5) mm, hairs stiff, 0.5 mm; petals not pink-tinged, oblanceolate to oblong or narrowly elliptic, 2.5–5 mm, apex rounded to truncate, sometimes slightly emarginate or mucronate; filaments white, 0.5–2 × 0.4–0.6 mm, glabrous or sparsely pilose adaxially, anthers 0.5–0.9 mm; carpels (10–)12–18(–20); styles 1.8–2.2 mm. |
Achenes | brown, 2–2.7 mm, smooth. |
brown to dark brown, 1.5–2 mm. |
Horkelia howellii |
Horkelia hispidula |
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Phenology | Flowering summer. | Flowering summer. |
Habitat | Chaparral, oak-conifer woodlands, mainly on serpentine soil | Dry, rocky alpine flats, in subalpine conifer woodlands |
Elevation | 60–1200 m (200–3900 ft) | 3000–3400 m (9800–11200 ft) |
Distribution |
CA; OR
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CA; NV |
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.) |
Of conservation concern. When describing Horkelia hispidula, Rydberg associated it with H. sericata in his group Sericatae. The species is known only from the White Mountains of California and adjacent Nevada. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Source | FNA vol. 9, p. 265. | FNA vol. 9, p. 249. |
Parent taxa | Rosaceae > subfam. Rosoideae > tribe Potentilleae > Horkelia > sect. Tridentatae | Rosaceae > subfam. Rosoideae > tribe Potentilleae > Horkelia > sect. Hispidulae |
Sibling taxa | ||
Synonyms | Potentilla howellii | Potentilla hispidula |
Name authority | (Greene) Rydberg: Bull. Torrey Bot. Club 25: 55. (1898) | Rydberg: in N. L. Britton et al., N. Amer. Fl. 22: 278. (1908) |
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