Horkelia sect. Tridentatae
Horkelia daucifolia
carrot leafed horkelia, carrot-leaf horkelia
decumbent to erect, 0.5–5 dm.
ascending to erect, 1.5–3.5 dm, hairs 2–3 mm proximally, glands sparse to dense distally.
planar to ± cylindric;
stipules entire, forked, or pinnately divided into linear to filiform lobes;
leaflets 2–20 per side, separate to ± overlapping, divided either 1/2–3/4+ to midrib into (0–)2–15 ultimate lobes or teeth not restricted to apex, or 1/10–1/4 or less to midrib into (0–)3(–5) teeth restricted to apex.
weakly planar to loosely cylindric, (4–)5–12(–17) × 0.8–3(–4) cm, usually sericeous to villous, sometimes glabrate;
stipules pinnately divided into 3–7 linear to filiform lobes;
leaflets 5–10 per side, ± overlapping, obovate to broadly obcordate, 5–15(–25) × 5–20 mm, ± as wide as long, divided 3/4+ to midrib into (0–)2–15 linear to oblanceolate lobes 0.4–2(–3) mm wide, these not restricted to apex.
3–6;
stipules 8–15 mm, deeply 3–7-lobed proximally, 1–3-lobed distally.
open to ± congested, flowers arranged individually, in corymbiform clusters, and/or in capitate or non-capitate glomerules.
open to ± congested, flowers arranged individually or in ± corymbiform clusters.
remaining straight, outermost sometimes ± reflexed in congested inflorescences, 1–10(–20) mm.
2–10(–20) mm.
epicalyx bractlets linear to lanceolate or narrowly elliptic, 0.2–0.5(–0.8) mm wide, entire;
hypanthium interior usually glabrous, sometimes pilose;
sepals obtuse to acute to slightly acuminate;
petals white to pink or cream, sometimes drying yellowish, linear or cuneate to obovate or obcordate, apex usually acute to rounded to emarginate, sometimes truncate, rarely mucronate;
filaments white, glabrous, anthers longer or shorter than wide;
carpels 2–15(–20).
10–15 mm diam.;
epicalyx bractlets linear to linear-lanceolate, 2.5–3.5 × 0.5 mm, 2/3 to ± equal to length of sepals;
hypanthium 1–1.5 × 3.5–5 mm, less than 1/2 as deep as wide, interior glabrous;
sepals ± spreading, abaxially green, 3.5–7.5 mm;
petals white to cream, often drying yellowish, cuneate to obcordate, (3.5–)4–8 × 2–8 mm, apex ± emarginate, sometimes rounded;
filaments 1–3 × 0.5–1.5 mm, anthers 0.5–0.8 mm;
carpels 5–15, styles 2–4 mm.
1.5–3 mm, smooth or rugose.
dark brown, 2.4–3 mm, smooth to ± roughened.
Horkelia sect. Tridentatae
Horkelia daucifolia
Species 5 (5 in the flora).
P. A. Rydberg (1908c) assigned the species here composing this section to three of his unranked groups: Hirsutae, Sericatae (also including Horkelia hispidula), and Tridentatae, validated inadvertently as sections by O. A. Stevens in the index to volume 22 of North American Flora. In addition to lacking the characteristic Horkelia odor, plants are often rosette-forming from simple caudices; stipules are sometimes highly divided; and leaflets are either few-toothed or deeply lobed. The section is centered in the Siskiyou-Klamath region of northwestern California and southwestern Oregon, with some affinity for ultramafic substrates. Horkelia tridentata extends south in the Sierra Nevada; H. congesta is a component of the Willamette Valley flora. Much of the variation in the section is highly localized, with a full series of intergrading morphologies, indicative of a relatively recent and active radiation. More segregates are recognized here than in some recent floras (M. E. Peck 1941; P. A. Munz 1959; B. Ertter 1993d), and additional variants are likely to warrant taxonomic recognition.
(Discussion copyrighted by Flora of North America; reprinted with permission.)
Varieties 3 (3 in the flora).
D. D. Keck (1938) decided that the leaflet characters previously used to recognize segregates of Horkelia daucifolia were random variables that have not become localized into geographic subunits. At the same time, he established subsp. latior D. D. Keck to accommodate a single collection with leaves approaching those of H. sericata, with the speculation that the population was an amphiploid derivative of the two species. Subsequent collections from the same general area (Scott Mountain, Siskiyou County, California) provide a full range of variation between the extreme with exceptionally wide leaflet lobes and the typical form occurring at the base of the mountain. This variant of the species is accordingly not recognized here, but the extremes with narrower, more numerous leaflet lobes are recognized as varieties that coincide with major river drainages (B. Ertter and J. L. Reveal 2007).
In the descriptions below, the pedicels of all varieties are sparsely pilose in addition to being puberulent or not.
(Discussion copyrighted by Flora of North America; reprinted with permission.)
1. Leaflets 2–6 per side, separate to slightly overlapping, divided into (0–)3(–5) teeth restricted to apex; inflorescences: flowers usually arranged in ± capitate glomerules, sometimes in corymbiform clusters | → 2 |
1. Leaflets 5–20 per side, ± overlapping, divided into (0–)2–15 linear to elliptic or oblanceolate lobes or teeth not restricted to apex; inflorescences: flowers arranged individually, in corymbiform clusters, and/or in usually non-capitate glomerules | → 3 |
2. Petals ± obovate, (1.5–)2–5 mm wide; stems: glands dense distally; Oregon, barely in nw California. | H. congesta |
2. Petals linear to broadly oblanceolate, 0.3–1.5 mm wide; stems: glands absent or sparse distally; California, barely in sw Oregon. | H. tridentata |
3. Leaflets 5–10 per side, 5–15(–25) mm, divided 3/4+ to midrib into (0–)2–15 lobes; stems: hairs 2–3 mm proximally; inflorescences open to ± congested, flowers arranged individually or in ± corymbiform clusters; petals white to cream, often drying yellowish. | H. daucifolia |
3. Leaflets (8–)10–20 per side, 2–10(–15) mm, divided ± 1/2–3/4 to midrib into (0–)2–4 lobes; stems: hairs 1 mm proximally; inflorescences open, flowers arranged individually and/or in non-capitate glomerules; petals white to pink or red-veined | → 4 |
4. Plants silvery; basal leaves densely sericeous, 3–10 cm, stipules usually entire or forked, rarely pinnately divided. | H. sericata |
4. Plants ± green; basal leaves usually villous to pilose, often glabrate, 5–15 cm, stipules deeply 2-lobed or pinnately divided into 3–5 lobes. | H. howellii |
1. Leaflet lobes 2–5(–8), linear to oblanceolate, 1–2(–3) mm wide; petals cuneate to obovate, 2–4 mm wide. | var. daucifolia |
1. Leaflet lobes (2–)5–15, linear, 0.4–1 mm wide; petals broadly obovate to obcordate, 4–8 mm wide | → 2 |
2. Pedicels 2–7(–10) mm, puberulent, eglandular; Oregon. | var. caruifolia |
2. Pedicels 5–10(–20) mm, not puberulent, minutely glandular; California. | var. indicta |
CA
OR
Flora NW
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