OregonFlora: Erigeron engelmannii vs. Erigeron coulteri

	Erigeron disparipilus (synonym of Erigeron engelmannii)	Erigeron coulteri
	Snake River daisy, white cushion fleabane	Coulter's fleabane
Habit	Plants perennial, 8–22 cm; taprooted, with branching caudices.	Plants perennial, 15–55 cm; roots fibrous, rhizomatous, occasionally with branching caudices.
Stems	erect, sparsely to moderately hirsute to strigose, eglandular.	erect, sparsely villous, eglandular.
Basal leaves	persistent, narrowly spatulate to narrowly oblanceolate-elliptic, 30–80 × 3–5 mm; margins entire, with 1 prominent vein; surfaces moderately to densely strigose, eglandular.	occasionally withering by flowering, broadly oblanceolate-elliptic, 40–150 × 10–25 mm; margins entire or occasionally with poorly developed teeth; surfaces sparsely strigose or hirsute, eglandular.
Cauline leaves	few, linear, 10–40 × 1–3 mm, reduced distally.	lanceolate to elliptic, 10–80 × 2.5–25(30) mm, gradually reduced distally, bases clasping; margins entire or with minute teeth.
Involucres	3.5–8 × 12–18 mm.	5–8 × 11–17 mm.
Ray florets	25–50, white or cream, occasionally fading to pink; rays 4–8 × 1–3 mm.	60–110, white; rays 8–15 × 0.5–1 mm.
Disc florets	corollas 3–4 mm.	corollas 3–5 mm.
Phyllaries	in 2–3 series, usually with dark green medial area with or without orange stripe; surfaces moderately to densely hirsute or strigose, moderately to densely glandular.	in 2–3 series; surfaces moderately to densely hirsute or villous, eglandular to minutely glandular.
Fruits	1.5–3 mm, sparsely to moderately strigose; inner pappi of numerous barbellate bristles.	1.5–2 mm, sparsely strigose; inner pappi of numerous barbellate bristles.
Heads	usually 1, radiate.	1(3), radiate.
2n		=18.

	Erigeron disparipilus	Erigeron coulteri
Distribution	[WildflowerSearch map] [BONAP county map]	[WildflowerSearch map] [BONAP county map]
Discussion	Open rocky areas, ridges. Flowering Jun–Jul. 1100–1800 m. BW. ID, WA. Native. Some floras recognize plants with stem hairs in the same orientation (versus mixed) as E. davisii. The ranges and habitat of these taxa are, however, sympatric. Until further evidence shows otherwise, there is no compelling reason to recognize E. davisii as distinct from E. disparipilus.	Moist coniferous forests, wet meadows. Flowering Jun–Aug. 1100–2000 m. BW. CA, ID, NV; northeast to MT, east to WY, southeast to NM. Native.
Source	Flora of Oregon, volume 2, page 255 James Riser, Stephen Meyers	Flora of Oregon, volume 2, page 255 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. 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	E. acris, E. aliceae, E. annuus, E. aphanactis, E. aureus, E. bloomeri, E. cascadensis, E. cervinus, E. chrysopsidis, E. compositus, E. corymbosus, 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 davisii, Erigeron engelmannii, Erigeron engelmannii ssp. davisii, Erigeron engelmannii var. davisii
Web links	Local floras: OR Local Web sites: Flora NW, PNW Herbaria 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 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 coulteri

Snake River daisy, white cushion fleabane

Coulter's fleabane

Habit

Plants perennial, 8–22 cm; taprooted, with branching caudices.

Plants perennial, 15–55 cm; roots fibrous, rhizomatous, occasionally with branching caudices.

Stems

erect, sparsely to moderately hirsute to strigose, eglandular.

erect, sparsely villous, eglandular.

Basal leaves

persistent, narrowly spatulate to narrowly oblanceolate-elliptic, 30–80 × 3–5 mm;

margins entire, with 1 prominent vein;

surfaces moderately to densely strigose, eglandular.

occasionally withering by flowering, broadly oblanceolate-elliptic, 40–150 × 10–25 mm;

margins entire or occasionally with poorly developed teeth;

surfaces sparsely strigose or hirsute, eglandular.

Cauline leaves

few, linear, 10–40 × 1–3 mm, reduced distally.

lanceolate to elliptic, 10–80 × 2.5–25(30) mm, gradually reduced distally, bases clasping;

margins entire or with minute teeth.

Involucres

3.5–8 × 12–18 mm.

5–8 × 11–17 mm.

Ray florets

25–50, white or cream, occasionally fading to pink;

rays 4–8 × 1–3 mm.

60–110, white;

rays 8–15 × 0.5–1 mm.

Disc florets

corollas 3–4 mm.

corollas 3–5 mm.

Phyllaries

in 2–3 series, usually with dark green medial area with or without orange stripe;

surfaces moderately to densely hirsute or strigose, moderately to densely glandular.

in 2–3 series;

surfaces moderately to densely hirsute or villous, eglandular to minutely glandular.

Fruits

1.5–3 mm, sparsely to moderately strigose;

inner pappi of numerous barbellate bristles.

1.5–2 mm, sparsely strigose;

inner pappi of numerous barbellate bristles.

Heads

usually 1, radiate.

1(3), radiate.

=18.

Erigeron coulteri

Distribution

[WildflowerSearch map]

[BONAP county map]

[WildflowerSearch map]

[BONAP county map]

Discussion

Open rocky areas, ridges. Flowering Jun–Jul. 1100–1800 m. BW. ID, WA. Native.

Some floras recognize plants with stem hairs in the same orientation (versus mixed) as E. davisii. The ranges and habitat of these taxa are, however, sympatric. Until further evidence shows otherwise, there is no compelling reason to recognize E. davisii as distinct from E. disparipilus.

Moist coniferous forests, wet meadows. Flowering Jun–Aug. 1100–2000 m. BW. CA, ID, NV; northeast to MT, east to WY, southeast to NM. Native.

Source

Flora of Oregon, volume 2, page 255
James Riser, Stephen Meyers

Sibling taxa