The green links below add additional plants to the comparison table. Blue links lead to other Web sites.
enable glossary links

Bolander's horkelia, border horkelia

Howell's horkelia, Klamath horkelia

Habit Plants openly matted, grayish. Plants tufted to openly matted, ± green.
Stems

ascending to erect, 1–3(–4.5) dm, hairs ascending to appressed.

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

Basal leaves

± planar, 3–8(–9) × 0.7–1.5 cm;

stipules entire;

leaflets 6–9 per side, separate to ± overlapping at least distally, ± cuneate to obovate, 4–10 × 2–7 mm, 1/2 to nearly as wide as long, divided 1/3 to midrib into 3–6 acute, sometimes obtuse, teeth, densely strigulose, often villous marginally or at least apically.

± 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

(2 or)3–6.

(2 or)3–5;

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

Inflorescences

± congested to open, most flowers arranged in glomerules.

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

Pedicels

(1–)2–4(–6) mm.

1–6(–12) mm.

Flowers

10 mm diam.;

epicalyx bractlets elliptic-lanceolate, (1.5–)1.8–3 × 0.5–1 mm, ± 2/3 length of sepals, entire;

hypanthium 1–1.5 × 2–4 mm, less than 1/2 as deep as wide, interior slightly pilose;

sepals spreading to ± reflexed, lanceolate, (2.5–)3–4 mm;

petals oblong to oblanceolate, 3–5.5 × 1.5–2 mm, apex rounded to slightly emarginate;

filaments 0.5–2 × 0.3–0.4 mm, anthers (0.4–)0.5–0.8 mm;

carpels 10–20(–27);

styles (1–)1.5–2 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 to dark brown, 1–1.3 mm, usually faintly roughened.

brown, 2–2.7 mm, smooth.

Horkelia bolanderi

Horkelia howellii

Phenology Flowering summer. Flowering summer.
Habitat Edges of vernal lakes, meadows, seeps, in grasslands, conifer woodlands Chaparral, oak-conifer woodlands, mainly on serpentine soil
Elevation 400–1100 m (1300–3600 ft) 60–1200 m (200–3900 ft)
Distribution
from FNA
CA
[WildflowerSearch map]
[BONAP county map]
from FNA
CA; OR
[WildflowerSearch map]
[BONAP county map]
Discussion

Of conservation concern.

W. L. Jepson ([1923–1925]) and P. A. Munz and I. M. Johnston (1925) independently adopted an expanded circumscription of Potentilla bolanderi that included four species of Horkelia recognized by P. A. Rydberg (1908c): H. bernardina, H. bolanderi, H. clevelandii, and H. rydbergii. These were treated as three varieties, which D. D. Keck (1938) converted to subspecies as H. bolanderi subsp. bolanderi, subsp. clevelandii, and subsp. parryi, the last encompassing H. bernardina and H. rydbergii. These subspecies were restored to species rank by B. Ertter (1993c) as H. bolanderi, H. clevelandii, and H. rydbergii, along with the establishment of H. yadonii to accommodate populations from Monterey County assigned to subsp. parryi by Keck.

As now circumscribed, Horkelia bolanderi is known from five locations in the northern Coast Ranges in Colusa, Lake, and Mendocino counties; records from more southerly localities would be referenced to one of the segregate species discussed above.

(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.)

Source FNA vol. 9, p. 251. FNA vol. 9, p. 265.
Parent taxa Rosaceae > subfam. Rosoideae > tribe Potentilleae > Horkelia > sect. Horkelia Rosaceae > subfam. Rosoideae > tribe Potentilleae > Horkelia > sect. Tridentatae
Sibling taxa
H. californica, H. clevelandii, H. congesta, H. cuneata, H. daucifolia, H. fusca, 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
Synonyms Potentilla bolanderi Potentilla howellii
Name authority A. Gray: Proc. Amer. Acad. Arts 7: 338. (1868) (Greene) Rydberg: Bull. Torrey Bot. Club 25: 55. (1898)
Web links