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Bolander's horkelia, border horkelia

Ramona horkelia

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

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

erect, 2–6(–8) dm, hairs spreading.

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.

planar, 4–13 × 2–3.5(–4) cm;

stipules entire or basally lobed;

leaflets 1–3 per side, separate, oblong to obovate, 10–30 × 5–12(–15) mm, ± 1/2 as wide as long, divided 1/6–1/4 to midrib into (15–)20–30 acute to obtuse teeth, sparsely short-pilose to glabrate, especially adaxially.

Cauline leaves

(2 or)3–6.

4–7.

Inflorescences

± congested to open, most flowers arranged in glomerules.

open, flowers arranged individually.

Pedicels

(1–)2–4(–6) mm.

4–20(–30) 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.

12–17 mm diam.;

epicalyx bractlets broadly ovate, 3–4.5 × 2–3 mm, ± 2/3 length of sepals, entire;

hypanthium 1.5–2 × 5–8 mm, less than 1/2 as deep as wide, interior glabrous;

sepals ± reflexed, broadly ovate, 3.5–5.5 mm;

petals obovate to round, 5–7 × (3–)4–7 mm, apex ± rounded;

filaments 1–2 × 0.5–2 mm, anthers 0.8–1 mm;

carpels 50–80;

styles 1.5–3 mm.

Achenes

brown to dark brown, 1–1.3 mm, usually faintly roughened.

brown, 1.3–1.5 mm, smooth.

Horkelia bolanderi

Horkelia truncata

Phenology Flowering summer. Flowering summer.
Habitat Edges of vernal lakes, meadows, seeps, in grasslands, conifer woodlands Dry clay soil, in chaparral communities, oak woodlands
Elevation 400–1100 m (1300–3600 ft) 400–1300 m (1300–4300 ft)
Distribution
from FNA
CA
[WildflowerSearch map]
[BONAP county map]
from FNA
CA; Mexico (Baja California)
[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.

Horkelia truncata is confined to the Peninsular Ranges of San Diego County, California, and northern Baja California, Mexico. Plants of the species are unusual in Horkelia in that the terminal leaflet is usually notably larger than the lateral leaflets, unlobed, and distinct, rather than confluent with the distal lateral ones.

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

Source FNA vol. 9, p. 251. FNA vol. 9, p. 256.
Parent taxa Rosaceae > subfam. Rosoideae > tribe Potentilleae > Horkelia > sect. Horkelia Rosaceae > subfam. Rosoideae > tribe Potentilleae > Horkelia > sect. Horkelia
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. howellii, H. marinensis, H. parryi, H. rydbergii, H. sericata, H. tenuiloba, H. tridentata, H. tularensis, H. wilderae, H. yadonii
Synonyms Potentilla bolanderi Potentilla truncata
Name authority A. Gray: Proc. Amer. Acad. Arts 7: 338. (1868) Rydberg: in N. L. Britton et al., N. Amer. Fl. 22: 274. (1908)
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