Erigeron filifolius |
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Peck's threadleaf fleabane, thread-leaf daisy, thread-leaf fleabane |
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Habit | Perennials, 10–30(–50) cm; taprooted, caudices multicipital, often with relatively short and thin, stemlike, lignescent branches. |
Stems | erect, sparsely to densely strigose (hairs loosely appressed to ascending, fine), densely white-strigose at least proximally, eglandular. |
Leaves | basal (usually persistent, not clustered as rosettes) and cauline; basal blades linear to filiform, 10–80 × 0.5–2.5(–3.5) mm; cauline gradually or little reduced distally, margins entire, faces sparsely to moderately strigose, eglandular. |
Involucres | 4–7 × 5–-18 mm. |
Ray florets | (15–)20–125; corollas usually blue, sometimes white, pink, or pale lavender, 3–13 mm, laminae coiling. |
Disc corollas | 2.5–5.5 mm. |
Phyllaries | in (2–)3–4 series, loosely strigose to hirsute or nearly villous, densely to sparsely minutely glandular. |
Heads | 1–5(–10+) from distal branches, tending to be in corymbiform arrays. |
Cypselae | 1.4–1.8(–2) mm, 2-nerved, faces sparsely strigose to glabrate; pappi: outer of setae, inner of 20–30 bristles. |
2n | = 18. |
Erigeron filifolius |
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Phenology | Flowering May–Aug. |
Habitat | Dry, rocky or sandy soil, lava beds, bitterbrush, sagebrush, juniper, ponderosa pine |
Elevation | 400–2400 m (1300–7900 ft) |
Distribution |
CA; ID; MT; NV; OR; UT; WA; BC
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Discussion | The densely white-strigose stem bases, linear-filiform leaves relatively unreduced distally, and relatively few heads with coiling, usually blue rays are distinctive for Erigeron filifolius. Proximal leaves are not clustered as a basal rosette; they are inserted on closely spaced nodes that are slightly more separated distally. Plants identified as var. robustior (with more ray florets, fewer heads, and thicker stems, centered in Oregon and Washington) intergrade with the typical form and apparently are separated arbitrarily. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Source | FNA vol. 20, p. 298. |
Parent taxa | Asteraceae > tribe Astereae > Erigeron |
Sibling taxa | |
Synonyms | Diplopappus filifolius, E. filifolius var. robustior |
Name authority | (Hooker) Nuttall: Trans. Amer. Philos. Soc., n. s. 7: 308. (1840) |
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