OregonFlora: Erigeron filifolius vs. Erigeron

	Erigeron filifolius	Erigeron
	threadleaf fleabane	daisy, fleabane
Habit	Plants perennial, 9–40 cm; taprooted, with branching caudices.	Herbs, rarely subshrubs or small shrubs annual, biennial, or perennial.
Stems	erect, moderately to densely strigose, eglandular.	usually erect to ascending, occasionally decumbent, glabrous to densely hirsute, glandular or eglandular.
Leaves		basal and/or cauline; basal sometimes withering by flowering, alternate, broadly obovate to oblanceolate to narrowly spatulate to linear; margins entire, lobed, or toothed; surfaces glabrous to densely hirsute, glandular or eglandular; cauline well developed or ± reduced distally, sessile or petiolate.
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.
Inflorescences		heads solitary on scapes or scape-like stems or few to many in corymb-, raceme-, or panicle-like arrays.
Involucres	4–6 × 7–11 mm.	turbinate or campanulate to hemispheric.
Receptacles		flat to conic, pitted; paleae 0.
Ray florets	20–40, white to purple; rays 3–9 × 0.7–1.5 mm.	0 or in 1(2) series, pistillate; rays usually strap-shaped, sometimes filiform, sometimes very short or lacking, white, pink, lavender, purple, blue, yellow, or cream-colored.
Disc florets	corollas 2–4 mm.	usually bisexual; corollas short, yellow.
Phyllaries	in 2–4 series; surfaces moderately to densely strigose or villous, sometimes nearly glabrous distally, densely minutely glandular.	usually in 2–3 series, numerous, often with a darkened medial or apical area; surfaces glabrous to densely hirsute, glandular or eglandular.
Fruits	1–3 mm, sparsely strigose; inner pappi of numerous barbellate bristles.	± oblong, flattened to ± cylindric, 2–7-veined, pappi of 2 series, outer of crowns; scales, or short bristles, inner of usually antrorsely barbellate, often accrescent; bristles, sometimes lacking.
Heads	1–5 in corymb-like arrays, radiate.	radiate, disciform, or discoid.
2n	=18.

	Erigeron filifolius	Erigeron
Distribution	[WildflowerSearch map] [BONAP county 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.	Temperate areas nearly worldwide. ~390 species; 40 species treated in Flora. Erigeron needs a modern generic revision. There is little consistency in the amount of variation warranting specific status. often, there is greater morphological variation within species (particularly among varieties) than between species. Many species are defined by morphological minutia and/or a single character (e.g., direction of stem hairs). Heads with both peripheral pistillate (ray) florets (in one or two series) and central disc florets (radiate heads) are most common. Heads lacking obvious ray florets may have inconspicuous or missing pistillate rays (disciform heads: E. aphanactis, E. chrysopsidis var. austiniae) or the pistillate flowers may actually be absent (discoid heads: E. bloomeri, E. inornatus, E. petrophilus). Pistillate flowers lacking conspicuous rays may be obscured by the involucres or adjacent disc floret pappi. Close inspection under magnification is needed before determining that the pistillate flowers are truly missing. Some individuals, especially if sterile, depauperate, or of poor quality, are not identifiable without direct comparison with reference material, if at all. The rays of pistillate flowers may change color upon drying; it is important to record flower color at time of collection. Due to shrinkage and curling of the pistillate flower rays on dried specimens, care must be taken when assessing whether rays are strap-shaped (usually greater than 0.5 mm wide) or filiform (less than 0.5 mm wide).
Source	Flora of Oregon, volume 2, page 256 James Riser, Stephen Meyers	Flora of Oregon, volume 1
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
Subordinate 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. filifolius, 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	Local floras: 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

threadleaf fleabane

daisy, fleabane

Habit

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

Herbs, rarely subshrubs or small shrubs annual, biennial, or perennial.

Stems

erect, moderately to densely strigose, eglandular.

usually erect to ascending, occasionally decumbent, glabrous to densely hirsute, glandular or eglandular.

Leaves

basal and/or cauline;

basal sometimes withering by flowering, alternate, broadly obovate to oblanceolate to narrowly spatulate to linear;

margins entire, lobed, or toothed;

surfaces glabrous to densely hirsute, glandular or eglandular;

cauline well developed or ± reduced distally, sessile or petiolate.

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.

Inflorescences

heads solitary on scapes or scape-like stems or few to many in corymb-, raceme-, or panicle-like arrays.

Involucres

4–6 × 7–11 mm.

turbinate or campanulate to hemispheric.

Receptacles

flat to conic, pitted;

paleae 0.

Ray florets

20–40, white to purple;

rays 3–9 × 0.7–1.5 mm.

0 or in 1(2) series, pistillate;

rays usually strap-shaped, sometimes filiform, sometimes very short or lacking, white, pink, lavender, purple, blue, yellow, or cream-colored.

Disc florets

corollas 2–4 mm.

usually bisexual;

corollas short, yellow.

Phyllaries

in 2–4 series;

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

usually in 2–3 series, numerous, often with a darkened medial or apical area;

surfaces glabrous to densely hirsute, glandular or eglandular.

Fruits

1–3 mm, sparsely strigose;

inner pappi of numerous barbellate bristles.

± oblong, flattened to ± cylindric, 2–7-veined, pappi of 2 series, outer of crowns; scales, or short bristles, inner of usually antrorsely barbellate, often accrescent; bristles, sometimes lacking.

Heads

1–5 in corymb-like arrays, radiate.

radiate, disciform, or discoid.

=18.

Erigeron

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.

Temperate areas nearly worldwide. ~390 species; 40 species treated in Flora.

Erigeron needs a modern generic revision. There is little consistency in the amount of variation warranting specific status. often, there is greater morphological variation within species (particularly among varieties) than between species. Many species are defined by morphological minutia and/or a single character (e.g., direction of stem hairs). Heads with both peripheral pistillate (ray) florets (in one or two series) and central disc florets (radiate heads) are most common. Heads lacking obvious ray florets may have inconspicuous or missing pistillate rays (disciform heads: E. aphanactis, E. chrysopsidis var. austiniae) or the pistillate flowers may actually be absent (discoid heads: E. bloomeri, E. inornatus, E. petrophilus). Pistillate flowers lacking conspicuous rays may be obscured by the involucres or adjacent disc floret pappi. Close inspection under magnification is needed before determining that the pistillate flowers are truly missing. Some individuals, especially if sterile, depauperate, or of poor quality, are not identifiable without direct comparison with reference material, if at all. The rays of pistillate flowers may change color upon drying; it is important to record flower color at time of collection. Due to shrinkage and curling of the pistillate flower rays on dried specimens, care must be taken when assessing whether rays are strap-shaped (usually greater than 0.5 mm wide) or filiform (less than 0.5 mm wide).

Source

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

Flora of Oregon, volume 1

Sibling taxa