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wedge leaf horkelia

Habit Plants ± green; eglandular hairs moderately abundant, spreading to ascending, glandular hairs usually evident. Plants forming tufts or mats, green to grayish, obscurely (and minutely) glandular, resinously aromatic, often strongly so.
Stems

ascending to erect, (1–)2–5 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

5–12 per side, elliptic to obovate or oblanceolate, 5–15 mm, distinctly pinnately veined.

Inflorescences

± open;

most flowers arranged in glomerules.

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

Pedicels

1–5 mm, proximalmost to 15 mm.

remaining straight, 1–30(–40) mm.

Flowers

hypanthium interior rim ± pilose;

petals oblanceolate, 2.5–3.5 mm wide;

filaments 1.5–3 × 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. cuneata

Horkelia sect. Horkelia

Phenology Flowering spring–summer.
Habitat Coastal sand dunes and hills, coastal scrub communities
Elevation 0–400 m (0–1300 ft)
Distribution
from FNA
CA
[BONAP county map]
from FNA
CA; nw Mexico
Discussion

Most extant populations of Horkelia cuneata are referable to var. cuneata or intermediates between it and the other two varieties, with the greatest concentrations around Monterey Bay and from Morro Bay to Santa Barbara. At its most distinctive, var. cuneata occurs from Santa Cruz to Los Angeles counties, often sharing habitat with var. sericea though also occurring somewhat more inland, but not as far inland as var. puberula. Although not as endangered as the extremes, unequivocal var. cuneata is far from abundant and shares some of the same threats to its prime coastal habitat.

(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. puberula, H. cuneata var. sericea
Subordinate taxa
H. bolanderi, H. californica, H. clevelandii, H. cuneata, H. marinensis, H. rydbergii, H. tenuiloba, H. truncata, H. yadonii
Synonyms Potentilla lindleyi var. lepida H. unranked Californicae, H. section Californicae, H. unranked Cuneatae, H. section Cuneatae, H. unranked Tenuilobae, H. section Tenuilobae
Name authority unknown unknown
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