Flora of North America species comparison

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Horkelia fusca

Horkelia howellii

dusky, horkelia, pinewoods, pinewoods horkelia, tawny horkelia

Howell's horkelia, Klamath horkelia
Habit Plants tufted to openly matted, ± green.
Stems

ascending to erect, (0.9–)1.5–5 dm, hairs 1 mm proximally, glands absent or sparse distally.
Basal leaves

(3–)4–20(–40) × (1–)1.5–4(–7) cm;

leaflets narrowly cuneate to obovate to flabellate, 5–30(–35) × 2–20(–30) mm, 1/3 as wide to wider than long, divided into linear or oblanceolate to obovate teeth or lobes, sparsely to ± densely short-villous or hirsute, sometimes glabrate.

± 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.
Cauline leaves

1–5(or 6).

(2 or)3–5;

stipules 5–12(–15) mm, entire to deeply 2–4-lobed or -toothed (usually on 1 side).
Inflorescences

open, flowers arranged individually and/or in non-capitate glomerules.
Pedicels

1–6(–12) mm.
Flowers

5–12 mm diam.;

epicalyx bractlets 1–3 mm, 1/2 length of to nearly equal to sepals;

hypanthium 1–3 × 2–4 mm, 1/2 to nearly as deep as wide;

sepals spreading to ± reflexed, narrowly to broadly lanceolate, (1.7–)2–4(–4.5) mm;

petals 2–6(–6.5) mm;

filaments 0.2–1.5 × (0.2–)0.4–0.6(–1) mm, anthers 0.4–0.6 mm;

styles 0.9–1.5 mm.

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.
Achenes

brown.

brown, 2–2.7 mm, smooth.

Horkelia fusca

Horkelia howellii
Phenology Flowering summer.
Habitat Chaparral, oak-conifer woodlands, mainly on serpentine soil
Elevation 60–1200 m [200–3900 ft]
Distribution
from FNA
CA; ID; NV; OR; WA; WY
[BONAP county map]
from FNA
CA; OR
[BONAP county map]
Discussion

Varieties 7 (7 in the flora).

Horkelia fusca represents the primary radiation of the genus beyond the California Floristic Province. Within California, H. fusca occurs in the Sierra Nevada and mountains of northern California, and it is the only representative of the genus extending beyond California and Oregon into Washington, Idaho, Nevada [with the possible exception of H. tridentata (10e. sect. Tridentatae) in Washoe County], and, questionably, Wyoming.

As here circumscribed, Horkelia fusca is the most diverse, most widely distributed species in the genus, with significant additional work needed to fully elucidate its variation patterns. The treatment presented here differs from that of D. D. Keck (1938) and B. Ertter (1993d) in using the rank variety instead of subspecies, circumscribing var. capitata more narrowly, and transferring the application of var. pseudocapitata from what is here called var. brownii to the bulk of what had been subsp. capitata (Lindley) D. D. Keck (B. Ertter and J. L. Reveal 2007).

There are two types of basal leaves in plants of Horkelia fusca. The ephemeral early-season leaves have leaflets that tend to be broadly cuneate-obovate, shallowly toothed, densely glandular but otherwise sparsely hairy, and deeply veined. The leaf features described below are drawn from the more persistent, mid season leaves that predominate at peak flowering and differ more strongly among varieties.

Petals of first-formed flowers are often larger than average; end-of-season petals can be smaller than average.

Although Montana is sometimes included in the range of Horkelia fusca, such references are based only on potential occurrence (W. E. Booth and J. C. Wright 1959).

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

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.)
Parent taxa Rosaceae > subfam. Rosoideae > tribe Potentilleae > Horkelia > sect. Capitatae Rosaceae > subfam. Rosoideae > tribe Potentilleae > Horkelia > sect. Tridentatae
Sibling taxa
H. bolanderi, H. californica, H. clevelandii, H. congesta, H. cuneata, H. daucifolia, H. hendersonii, H. hispidula, H. howellii, H. marinensis, H. parryi, H. rydbergii, H. sericata, H. tenuiloba, H. tridentata, H. truncata, H. tularensis, H. wilderae, H. yadonii
H. bolanderi, H. californica, H. clevelandii, H. congesta, H. cuneata, H. daucifolia, H. fusca, H. hendersonii, H. hispidula, H. marinensis, H. parryi, H. rydbergii, H. sericata, H. tenuiloba, H. tridentata, H. truncata, H. tularensis, H. wilderae, H. yadonii
Subordinate taxa
H. fusca var. brownii, H. fusca var. capitata, H. fusca var. filicoides, H. fusca var. fusca, H. fusca var. parviflora, H. fusca var. pseudocapitata, H. fusca var. tenella
Key
1. Leaflets divided ± 1/2–3/4+ to midrib
→ 2
1. Leaflets divided less than 1/2 to midrib
→ 4
2. Inflorescences usually with flowers arranged individually; sw Oregon.
var. filicoides
2. Inflorescences composed of 3–20-flowered glomerules, (flowers rarely arranged individually in var. fusca); ne California, nw Oregon, sw Washington
→ 3
3. Leaflets divided ± 1/2 to midrib, 5–18(–20) × 4–15 mm; petals 3–5 mm; filaments 0.5–1.3 mm, longer than wide; nw Oregon, sw Washington.
var. fusca
3. Leaflets divided 3/4+ to midrib, 5–10(–15) × 2–10(–20) mm; petals 2–3(–4) mm; filaments 0.2–0.5 mm, wider than long; ne California.
var. tenella
4. Leaves grayish, surfaces often obscured, ± densely short-villous; leaflets narrowly to broadly cuneate, usually 1/3–1/2 as wide as long; ne California, adjacent Oregon and Nevada.
var. brownii
4. Leaves green, surfaces not obscured, ± short-hirsute, villous, or glabrate; leaflets cuneate to broadly obovate, 1/2 to wider than long; California to Washington, Idaho, Wyoming
→ 5
5. Inflorescences dark reddish purple, densely congested, bracts acuminate-lobed, obscuring pedicels and flowers even at maturity, glandular hairs usually conspicuously red-septate; epicalyx bractlets (2–)3.5–5(–6) mm; cauline leaves 3–6, leaflets of proximalmost 3–5 per side; ne Oregon, se Washington, n Idaho.
var. capitata
5. Inflorescences green to reddish purple, congested to open, bracts acute-lobed, not obscuring pedicels and flowers at maturity, glandular hairs not or obscurely red-septate; epicalyx bractlets 1–3.5(–4) mm; cauline leaves 1–4(or 5), leaflets of proximalmost 2–4(or 5) per side; Cascade-Sierra axis of Oregon, California, e to Wyoming and n Nevada
→ 6
6. Petals (3–)4–6 mm; leaflets 10–30(–35) × (5–)10–20(–25) mm; epicalyx bractlets 2–3.5(–4) mm; mountains in and bordering n Intermountain Region, ne California, n Nevada, se Oregon, s Idaho.
var. pseudocapitata
6. Petals 2–4.5(–6.5) mm; leaflets 5–15(–20) × (2–)5–10(–15) mm; epicalyx bractlets 1–2(–3) mm; Sierra Nevada, California and Nevada, to Cascade Ranges, c Oregon, and mountains of c Idaho, adjacent Wyoming.
var. parviflora
Synonyms Potentilla douglasii Potentilla howellii
Name authority Lindley: Edwards’s Bot. Reg. 23: plate 1997. (1837) (Greene) Rydberg: Bull. Torrey Bot. Club 25: 55. (1898)
Source FNA vol. 9, p. 259. Treatment authors: Barbara Ertter, James L. Reveal. FNA vol. 9, p. 265. Treatment authors: Barbara Ertter, James L. Reveal.
Web links 
Unless otherwise noted, all data comes from the online version of the Flora of North America, who have made most of their content available via a Creative Commons license (CC BY 4.0).



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