Horkelia tridentata var. flavescens

(Rydberg) Ertter & Reveal

Novon 17: 320. 2007.

Common names: Hairycup horkelia
Endemic
Basionym: Horkelia flavescens Rydberg Monogr. N. Amer. Potentilleae, 138, plate 75. 1898
Synonyms: H. tridentata subsp. flavescens (Rydberg) D. D. Keck Potentilla tilingii var. flavescens (Rydberg) J. T. Howell
Treatment appears in FNA Volume 9. Treatment on page 270. Mentioned on page 268, 269.

Stems ± decumbent, 0.5–2.5 (–4.5) dm. Inflorescences composed of usually 1 3–25-flowered ± corymbiform cluster. Flowers 6–10 mm diam.; hypanthium 2.5–5 mm diam., interior pilose (except in some North Coast Ranges populations); petals ± broadly oblanceolate, (1–) 1.5–3 (–4) × 0.5–1.5 mm, often shorter than sepals, apex obtuse to rounded or mucronate; filaments 1–2 × 0.2–0.4 (–0.8) mm, anthers 0.3–0.5 mm; styles 1.5–2.5 mm. Achenes 2–2.5 mm, strongly rugose.


Phenology: Flowering summer.
Habitat: Open areas, primarily in conifer woodlands, often on serpentine soil
Elevation: 700–2000 m

Discussion

Variety flavescens occurs primarily in the mountains of northwestern California, from Mendocino to Siskiyou counties. A single collection is confirmed from Curry County, Oregon (Bear Camp Trail, Leach 4554, OSC); other collections from Curry and Josephine counties may be hybrids between this variety and Horkelia congesta var. nemorosa. A second cluster of populations occurs in central Plumas and adjacent Lassen counties, California, and historic collections are known from near Truckee on the border of Nevada and Placer counties, California. D. D. Keck (1938) suggested that this bicentric distribution may have resulted from the independent coalescence of the diagnostic characteristics of var. flavescens. The locality of a collection purportedly from Washoe County, Nevada (80 miles north of Reno, Brooks s.n., RENO) needs to be confirmed.

Selected References

None.

Lower Taxa

None.

"/2lengthofsepals" is not declared as a valid unit of measurement for this property.No values specified."dm" is not declared as a valid unit of measurement for this property.

light-brown +
2mm +  and 2.5mm +
shorter than wide +  and longer +
0.03 cm0.3 mm <br />3.0e-4 m <br /> (0.05 cm0.5 mm <br />5.0e-4 m <br />) +
truncate +  and emarginate +
Barbara Ertter +  and James L. Reveal +
(Rydberg) Ertter & Reveal +
compound +  and simple +
opposite +  and alternate +
3 cm30 mm <br />0.03 m <br /> (4 cm40 mm <br />0.04 m <br />) +
3 cm30 mm <br />0.03 m <br /> (12 cm120 mm <br />0.12 m <br />) +
1 cm10 mm <br />0.01 m <br /> (3 cm30 mm <br />0.03 m <br />) +
flattened +
Horkelia flavescens +
30 cm300 mm <br />0.3 m <br /> (40 cm400 mm <br />0.4 m <br />) +
planar +  and cylindric +
2 cm20 mm <br />0.02 m <br /> (30 cm300 mm <br />0.3 m <br />) +
reduced +
free +  and distinct +
Hairycup horkelia +
open to congested +
Calif. +  and Oreg. +
not +  and aggregated +
700–2000 m +
0.2 cm2 mm <br />0.002 m <br /> (0.3 cm3 mm <br />0.003 m <br />) +
linear +  and lanceolate or narrowly elliptic +
0.02 cm0.2 mm <br />2.0e-4 m <br /> (0.04 cm0.4 mm <br />4.0e-4 m <br />) +
0.04 cm0.4 mm <br />4.0e-4 m <br /> (0.08 cm0.8 mm <br />8.0e-4 m <br />) +
0.1 cm1 mm <br />0.001 m <br /> (0.2 cm2 mm <br />0.002 m <br />) +
flattened +
0.02 cm0.2 mm <br />2.0e-4 m <br /> (0.04 cm0.4 mm <br />4.0e-4 m <br />) +
open to congested +
0.6 cm6 mm <br />0.006 m <br /> (1 cm10 mm <br />0.01 m <br />) +
unisexual +  and bisexual +
not +  and aggregated +
obliquely ovoid +  and reniform +
0.08 cm0.8 mm <br />8.0e-4 m <br /> (0.3 cm3 mm <br />0.003 m <br />) +
open to congested +
Open areas, primarily in conifer woodlands, often on serpentine soil +
0.1 cm1 mm <br />0.001 m <br /> (0.3 cm3 mm <br />0.003 m <br />) +
0.25 cm2.5 mm <br />0.0025 m <br /> (0.5 cm5 mm <br />0.005 m <br />) +
0.1 cm1 mm <br />0.001 m <br /> (0.25 cm2.5 mm <br />0.0025 m <br />) +
0.1 cm1 mm <br />0.001 m <br /> (0.55 cm5.5 mm <br />0.0055 m <br />) +
crassinucellate +
opposite +  and alternate +
marcescent +
winter-persistent +
separate +  and slightly overlapping +
2 cm20 mm <br />0.02 m <br /> (3 cm30 mm <br />0.03 m <br />) +
0.7 cm7 mm <br />0.007 m <br /> (1 cm10 mm <br />0.01 m <br />) +
0.5 cm5 mm <br />0.005 m <br /> (2 cm20 mm <br />0.02 m <br />) +
divided +, elliptic +  and cuneate-oblong +
0.15 cm1.5 mm <br />0.0015 m <br /> (?) +  and 0.7 cm7 mm <br />0.007 m <br /> (?) +
linear +  and filiform +
palmate +  and pinnate +
shallowly toothed +  and deeply divided +
aromatic +
inferior +  and superior +
clustered +, biseriate +  and superposed +
0.6 cm6 mm <br />0.006 m <br /> (1 cm10 mm <br />0.01 m <br />) +
0.2 cm2 mm <br />0.002 m <br /> (0.6 cm6 mm <br />0.006 m <br />) +
0.3 cm3 mm <br />0.003 m <br /> (0.4 cm4 mm <br />0.004 m <br />) +
0 (?) +  and 4 (?) +
free +  and distinct +
0.15 cm1.5 mm <br />0.0015 m <br /> (0.3 cm3 mm <br />0.003 m <br />) +
0.05 cm0.5 mm <br />5.0e-4 m <br /> (0.15 cm1.5 mm <br />0.0015 m <br />) +
Flowering summer. +
adnate +, free +, connate +  and distinct +
not arillate +
abaxially green +  and reddish +
persistent +
free +  and distinct +
obtuse +  and acute +
0.15 cm1.5 mm <br />0.0015 m <br /> (0.3 cm3 mm <br />0.003 m <br />) +
free +  and distinct +
branched +  and simple +
stramineous +, reddish +  and green +
decumbent +  and nearly erect +
1 +  and 10 +
palmate +  and pinnate +
0.3 cm3 mm <br />0.003 m <br /> (1.2 cm12 mm <br />0.012 m <br />) +
deciduous +
distinct +
subterminal +
filiform +
rough-thickened +
0.15 cm1.5 mm <br />0.0015 m <br /> (0.25 cm2.5 mm <br />0.0025 m <br />) +
H. tridentata subsp. flavescens +  and Potentilla tilingii var. flavescens +
Horkelia tridentata var. flavescens +
Horkelia tridentata +
variety +
triangular +
1 cm10 mm <br />0.01 m <br /> (?) +
inconspicuous +
enlarged +
plant +  and rosette-forming +
hairy +  and inconspicuously conspicuously glandular +