Horkelia sericata
Horkelia clevelandii
Howell's horkelia, silky horkelia
Cleveland's horkelia
ascending to erect, 1.5–4.5 dm, hairs 1 mm proximally, glands absent or sparse distally.
± cylindric to weakly planar, 3–10 × 0.3–1.2 cm, densely sericeous, often villous on margins apically;
stipules usually entire or forked, rarely pinnately divided into linear lobes;
leaflets (8–)10–20 per side, ± overlapping, elliptic to flabellate, 2–8 × 1–4 mm, 1/2–2/3 as wide as long, divided ± 1/2+ to midrib into (0–)2–4 elliptic lobes 1–2 mm wide, these not restricted to apex.
(2 or)3–5;
stipules 3–8 mm, entire or shallowly 1–2-toothed.
open, flowers arranged individually and/or in non-capitate glomerules.
1–4 mm.
10 mm diam.;
epicalyx bractlets linear-lanceolate, 1.5–3 × 0.5 mm, ± 2/3 length of sepals;
hypanthium 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, 2–4 mm;
petals white to pink or red-veined, narrowly obcordate, 3–4.5(–7) × 2–3 mm, apex ± emarginate;
filaments 0.5–1.5 × 0.2–0.5 mm, anthers 0.4–0.6 mm;
carpels 2–6;
styles 1.5–2 mm.
brown, 2–2.5 mm, smooth.
= 28.
Horkelia sericata
Horkelia clevelandii
Of conservation concern.
D. D. Keck (1938) expanded the circumscription of Horkelia sericata to encompass the plants segregated here as H. howellii, on the grounds that intergradation is too extensive to justify taxonomic recognition of the extremes. In this evaluation, however, most collections can be unequivocally divided between plants with compact silvery-sericeous leaves with entire or forked stipules (H. sericata), and plants with larger, greener leaves and pinnately divided stipules (H. howellii). It is not known if the chromosome count provided by P. A. Munz (1959) was derived from H. howellii or H. sericata.
As here circumscribed, Horkelia sericata is a localized taxon known only from Curry County, Oregon, and the Gasquet serpentine area in adjacent Del Norte County, California.
(Discussion copyrighted by Flora of North America; reprinted with permission.)
Varieties 2 (1 in the flora).
The component of Horkelia clevelandii occurring in the Sierra San Pedro Mártir and most of the Sierra Juarez of northern Baja California, Mexico, is var. brevibracteata (Wiggins) Ertter & Reveal. It differs from var. clevelandii in tending to have a more compact and matted habit, shorter stems (1–3 dm), more numerous (11–16) pairs of smaller (4–8 mm) leaflets, shorter epicalyx bractlets (1.5–2 mm), and deeper hypanthia (2–2.5 mm).
(Discussion copyrighted by Flora of North America; reprinted with permission.)
CA
OR
Flora NW
PNW Herbaria
WildflowerSearch
iNaturalist
USDA Plants Database
