Horkelia sect. Hispidulae |
Horkelia tularensis |
|||||||||
---|---|---|---|---|---|---|---|---|---|---|
|
Kern Plateau horkelia, Tulare cinquefoil |
|||||||||
Habit | Plants forming dense mats, usually grayish green, sometimes reddish, inconspicuously glandular, not resinously aromatic. | Plants 1–4 dm diam. | ||||||||
Stems | decumbent to erect, 0.3–2.5 dm. |
decumbent to erect, 0.3–1.8(–2.5) dm. |
||||||||
Basal leaves | ± cylindric to weakly planar; stipules entire; leaflets 4–14 per side, overlapping at least distally, divided 1/2–3/4+ to midrib into 3–8 lobes not restricted to apex. |
2–8(–10) × 0.5–1.3 cm; leaflets 4–6(–10) per side, overlapping, cuneate to flabellate, 3–8 mm, divided 3/4+ to midrib into (3–)5–8 oblong to obovate or oblanceolate lobes, villous to pilose at least marginally or apically. |
||||||||
Cauline leaves | 1 or 2. |
|||||||||
Inflorescences | ± congested, flowers arranged in dense corymbiform clusters. |
|||||||||
Pedicels | remaining straight, 2–8(–12) mm. |
2–7 mm. |
||||||||
Flowers | epicalyx bractlets linear to lanceolate, 0.3–0.5(–0.8) mm wide, entire; hypanthium interior sparsely pilose to densely villous; sepals acute; petals white, sometimes pink-tinged, narrowly oblanceolate to narrowly elliptic or oblong, apex usually acute to rounded to truncate, sometimes slightly mucronate or emarginate; filaments white to pinkish, glabrous or sparsely pilose adaxially, anthers longer than wide; carpels 5–18(–20). |
3–15, 8–10 mm diam.; epicalyx bractlets linear-lanceolate, 1–2.5(–3) × 0.3–0.5(–0.8) mm, ± 2/3 length of sepals; hypanthium 1–1.5 × 2.5–4.5 mm, nearly 1/2 as deep as wide, interior sparsely pilose; sepals spreading to reflexed, broadly lanceolate, (2–)3–4.5(–5) mm, hairs stiff, 0.5–1 mm; petals not pink-tinged, narrowly oblanceolate to narrowly oblong, 2–4 mm, apex rounded to truncate, often slightly mucronate; filaments white, 1–2 × 0.3–0.5 mm, usually glabrous, rarely sparsely pilose, anthers 0.6–0.8 mm; carpels 5–12; styles 1.5–2 mm. |
||||||||
Achenes | 1.5–2.5 mm, smooth. |
light brown to brown, 2–2.5 mm. |
||||||||
Horkelia sect. Hispidulae |
Horkelia tularensis |
|||||||||
Phenology | Flowering summer. | |||||||||
Habitat | Dry, rocky metamorphic ridges, in subalpine conifer woodlands | |||||||||
Elevation | 2300–2900 m (7500–9500 ft) | |||||||||
Distribution | w United States |
CA |
||||||||
Discussion | Species 3 (3 in the flora). Section Hispidulae accommodates three widely separated, localized species, with plants all forming tight, densely hairy mats in rocky sites at elevations of 2000 to 3400 m in the White Mountains, southern Sierra Nevada, and Siskiyou Mountains of California, adjacent Nevada, and southwestern Oregon. When describing Horkelia tularensis (as Potentilla tularensis), Howell compared it to H. hispidula with the speculation that these interior species bordering the Great Basin were relicts of an evolutionary line distinct from the more coastal species. Given the geographic proximity to Horkeliella, which serves as a morphologic bridge between Horkelia and Ivesia, it is possible that sect. Hispidulae represents the relictual ancestral radiation within the genus. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Of conservation concern. Horkelia tularensis is known only from the Kern Plateau in Tulare County. Greenish and reddish plants can grow intermixed in a single population. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
||||||||
Key |
|
|||||||||
Source | FNA vol. 9, p. 248. | FNA vol. 9, p. 249. | ||||||||
Parent taxa | ||||||||||
Sibling taxa | ||||||||||
Subordinate taxa | ||||||||||
Synonyms | Potentilla tularensis | |||||||||
Name authority | Ertter & Reveal: Novon 17: 316. (2007) | (J. T. Howell) Munz: Suppl. Calif. Fl., 110. (1968) | ||||||||
Web links |