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coast horkelia, Kellogg's horkelia, wedgeleaf horkelia

Habit Plants grayish-sericeous; eglandular hairs dense, ascending to appressed, glandular hairs obscured. Plants forming tufts or mats, green to grayish, obscurely (and minutely) glandular, resinously aromatic, often strongly so.
Stems

decumbent to ascending, 2–5(–7.5) dm.

decumbent or ascending to erect, (0.5–)1–10(–12) dm.

Basal leaves

usually planar, sometimes ± cylindric;

stipules usually entire, sometimes basally lobed;

leaflets (1–)3–16(–20) per side, separate to overlapping, divided ± 1/6–3/4+ to midrib into 3–30(–60) teeth or lobes not restricted to apex.

Leaflets

5–10 per side, obovate, (5–)10–25(–30) mm, not distinctly pinnately veined.

Inflorescences

usually ± congested;

most flowers arranged in glomerules.

open to congested, flowers arranged individually, in usually non-capitate glomerules, and/or in corymbiform clusters.

Pedicels

1–3 mm, proximalmost to 12 mm.

remaining straight, 1–30(–40) mm.

Flowers

hypanthium interior rim densely pilose;

petals oblanceolate, 1.5–3 mm wide;

filaments 1–3 × 0.5–1 mm.

epicalyx bractlets narrowly elliptic-lanceolate to broadly ovate, 0.5–3 mm wide, usually entire, sometimes toothed;

hypanthium interior pilose or glabrous;

sepals acute;

petals white, oblong-oblanceolate to round, apex obtuse to truncate to emarginate;

filaments white, glabrous, anthers longer than wide;

carpels 10–200(–220).

Achenes

0.8–2 mm, usually smooth or slightly rugose, sometimes merely roughened.

2n

= 28.

Horkelia cuneata var. sericea

Horkelia sect. Horkelia

Phenology Flowering summer.
Habitat Coastal stabilized dunes and hills, coastal scrub communities
Elevation 0–200 m (0–700 ft)
Distribution
from FNA
CA
[BONAP county map]
from FNA
CA; nw Mexico
Discussion

Of conservation concern.

Historic populations of var. sericea occurred along the immediate coast from Alameda and Marin counties south at least to Santa Barbara County, with some littoral collections of Horkelia cuneata from Los Angeles and San Diego counties having some sericea characteristics. Reports from farther north are all based on misidentifications, for example, of H. californica in Sonoma County. The most distinctive specimens are from the northern populations in Alameda, Marin, San Francisco, and San Mateo counties, all of which apparently no longer exist. Of the recently confirmed extant populations, those that come closest to justifying continued recognition of var. sericea are in Monterey, San Luis Obispo, and Santa Cruz counties.

(Discussion copyrighted by Flora of North America; reprinted with permission.)

Species 9 (9 in the flora).

Section Horkelia encompasses the species that are most commonly encountered in heavily populated areas of California. Plants are notably glandular-viscid (unless obscured by dense vestiture) and have a distinctive resinous odor.

Previous revisions (for example, P. A. Rydberg 1908c; D. D. Keck 1938) have placed Horkelia frondosa (here treated as H. californica var. frondosa) at the beginning, implying that this is the least derived expression within the genus. Such an assumption is based on its gross resemblance to sympatric members of Drymocallis; molecular evidence (T. Eriksson et al. 1998; M. Lundberg et al. 2009; C. Dobeš and J. Paule 2010) confirms that this similarity is superficial. If, as speculated above, species composing sect. Hispidulae are relicts of the original radiation, then H. californica var. frondosa is actually one of the more derived members of the genus. Species within sect. Horkelia have been ordered here according to that interpretation.

(Discussion copyrighted by Flora of North America; reprinted with permission.)

Key
1. Leaflets 1–3 per side, sparsely short-pilose to glabrate, (15–)20–30-toothed 1/6–1/4 to midrib; petals obovate to round, (3–)4–7 mm wide.
H. truncata
1. Leaflets (3–)5–16(–20) per side, hairy, 3–15(–30)-toothed or -lobed (collectively 10–60-toothed in H. californica) 1/6–3/4+ to midrib; petals narrowly obovate or oblanceolate to elliptic or oblong, 1–3(–4) mm wide
→ 2
2. Hypanthia 3–5.5 mm, 1/2 to nearly as deep as wide; epicalyx bractlets 4–6(–8) mm, ± equal to sepals, entire or toothed.
H. californica
2. Hypanthia 1–2(–3) mm, less than 1/2 as deep as wide (except H. clevelandii); epicalyx bractlets 1–4(–5) mm, shorter than sepals, entire
→ 3
3. Leaflets ± elliptic to obovate, divided less than 1/3 to midrib into (5–)10–15 teeth; epicalyx bractlets 1.5–3 mm wide.
H. cuneata
3. Leaflets cuneate or flabellate to ovate or nearly round, divided (1/5–)1/3–3/4+ to midrib into 3–10(–30 in H. yadonii) teeth or lobes; epicalyx bractlets 0.5–2(–2.5) mm wide
→ 4
4. Stems ± decumbent to ascending, 1–3.5(–4.5) dm; leaflets 5–10(–12) per side, cuneate, ± overlapping; inflorescences usually congested; plants matted; coastal.
H. marinensis
4. Stems ascending to erect, (0.5–)1–7 dm; leaflets 6–16(–20) per side, cuneate to flabellate or nearly round, separate to ± overlapping; inflorescences open to ± congested; plants tufted to matted; coastal or interior
→ 5
5. Epicalyx bractlets 1–2(–2.5) mm wide, lanceolate to ovate; anthers 0.8–1.2 mm; hypanthia 3–6.5 mm diam.
H. yadonii
5. Epicalyx bractlets 0.5–1(–1.5) mm wide, narrowly elliptic to broadly lanceolate; anthers 0.4–1 mm; hypanthia 2–4.5(–6) mm diam
→ 6
6. Stems: hairs ascending to appressed; plants usually grayish to grayish green; hypanthium interior pilose
→ 7
6. Stems: hairs ± spreading; plants green to grayish; hypanthium interior glabrous or pilose
→ 8
7. Carpels 20–50(–120); styles 2–4 mm; basal leaves (4–)8–20(–30) cm; Transverse Ranges, s California.
H. rydbergii
7. Carpels 10–20(–27); styles (1–)1.5–2 mm; basal leaves 3–8(–9) cm; Coast Ranges, n California.
H. bolanderi
8. Leaflets divided 1/2–3/4+ to midrib into linear to narrowly oblanceolate or narrowly elliptic lobes; hypanthium interior pilose; n Coast Ranges, California.
H. tenuiloba
8. Leaflets divided 1/3 to midrib into acute to obtuse teeth; hypanthium interior glabrous; Peninsular Ranges, s California.
H. clevelandii
Source FNA vol. 9, p. 255. FNA vol. 9, p. 250.
Parent taxa Rosaceae > subfam. Rosoideae > tribe Potentilleae > Horkelia > sect. Horkelia > Horkelia cuneata Rosaceae > subfam. Rosoideae > tribe Potentilleae > Horkelia
Sibling taxa
H. cuneata var. cuneata, H. cuneata var. puberula
Subordinate taxa
H. bolanderi, H. californica, H. clevelandii, H. cuneata, H. marinensis, H. rydbergii, H. tenuiloba, H. truncata, H. yadonii
Synonyms H. californica var. sericea, H. cuneata subsp. sericea, H. kelloggii, H. sericea, Potentilla kelloggii, P. lindleyi var. sericea H. unranked Californicae, H. section Californicae, H. unranked Cuneatae, H. section Cuneatae, H. unranked Tenuilobae, H. section Tenuilobae
Name authority (A. Gray) Ertter & Reveal: Novon 17: 319. (2007) unknown
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