OregonFlora: Erigeron filifolius

	Erigeron filifolius
	threadleaf fleabane
Habit	Plants perennial, 9–40 cm; taprooted, with branching caudices.
Stems	erect, moderately to densely strigose, eglandular.
Basal leaves	persistent, linear to filiform, 20–80 × 0.5–2 mm; margins entire; tips rounded to acute or acuminate; surfaces moderately to densely strigose.
Cauline leaves	gradually reduced distally or not.
Involucres	4–6 × 7–11 mm.
Ray florets	20–40, white to purple; rays 3–9 × 0.7–1.5 mm.
Disc florets	corollas 2–4 mm.
Phyllaries	in 2–4 series; surfaces moderately to densely strigose or villous, sometimes nearly glabrous distally, densely minutely glandular.
Fruits	1–3 mm, sparsely strigose; inner pappi of numerous barbellate bristles.
Heads	1–5 in corymb-like arrays, radiate.
2n	=18.

	Erigeron filifolius
Distribution	[WildflowerSearch map] [BONAP county map]
Discussion	Rocky areas, sagebrush, juniper and pine forests. Flowering Apr–Aug. 50–2200 m. BR, BW, Col, ECas, Lava, Owy. CA, ID, NV, WA; north to British Columbia, northeast to MT, southeast to UT. Native. If subspecific taxa were recognized, Oregon specimens would correspond to the typical variety.
Source	Flora of Oregon, volume 2, page 256 James Riser, Stephen Meyers
Sibling taxa	E. acris, E. aliceae, E. annuus, E. aphanactis, E. aureus, E. bloomeri, E. cascadensis, E. cervinus, E. chrysopsidis, E. compositus, E. corymbosus, E. coulteri, E. decumbens, E. disparipilus, E. divergens, E. eatonii, E. elegantulus, E. foliosus, E. glacialis, E. glaucus, E. howellii, E. inornatus, E. karvinskianus, E. klamathensis, E. latus, E. linearis, E. lonchophyllus, E. nivalis, E. oreganus, E. peregrinus, E. petrophilus, E. philadelphicus, E. poliospermus, E. pumilus, E. simplex, E. speciosus, E. stanselliae, E. strigosus, E. tener, E. vagus
Synonyms	Erigeron filifolius var. filifolius, Erigeron filifolius var. robustior
Web links	Local floras: BC, CA, OR, WA Local Web sites: CalFlora, CalPhotos, Flora NW, PNW Herbaria, Turner Photog. WildflowerSearch iNaturalist (observations) USDA Plants Database LBJ Wildflower Center SEINet Plants of the World Online Encyclopedia of Life Wikipedia Google Image Search

Erigeron filifolius

threadleaf fleabane

Habit

Plants perennial, 9–40 cm; taprooted, with branching caudices.

Stems

erect, moderately to densely strigose, eglandular.

Basal leaves

persistent, linear to filiform, 20–80 × 0.5–2 mm;

margins entire;

tips rounded to acute or acuminate;

surfaces moderately to densely strigose.

Cauline leaves

gradually reduced distally or not.

Involucres

4–6 × 7–11 mm.

Ray florets

20–40, white to purple;

rays 3–9 × 0.7–1.5 mm.

Disc florets

corollas 2–4 mm.

Phyllaries

in 2–4 series;

surfaces moderately to densely strigose or villous, sometimes nearly glabrous distally, densely minutely glandular.

Fruits

1–3 mm, sparsely strigose;

inner pappi of numerous barbellate bristles.

Heads

1–5 in corymb-like arrays, radiate.

=18.

Erigeron filifolius

Distribution

[WildflowerSearch map]

[BONAP county map]

Discussion

Rocky areas, sagebrush, juniper and pine forests. Flowering Apr–Aug. 50–2200 m. BR, BW, Col, ECas, Lava, Owy. CA, ID, NV, WA; north to British Columbia, northeast to MT, southeast to UT. Native.

If subspecific taxa were recognized, Oregon specimens would correspond to the typical variety.

Source

Flora of Oregon, volume 2, page 256
James Riser, Stephen Meyers

Sibling taxa