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Erigeron disparipilus

Snake River daisy, Snake River fleabane, white cushion fleabane

quill fleabane

Habit Perennials, 3–12 cm; taprooted, caudices branched. Perennials, 5–20 cm; rhizomatous, fibrous-rooted, forming diffuse systems of slender, rhizomelike caudex branches.
Stems

erect, densely pilose to hirsute or villoso-hirsute (hairs usually slightly ascending, loose, often mixed in orientations, of unequal lengths, relatively thin-based), eglandular.

ascending (bases usually purplish), glabrous or sparsely strigose (or hairs loosely spreading), eglandular.

Leaves

mostly basal (persistent), (petioles prominently ciliate, hairs thick-based, spreading);

blades linear to linear-oblanceolate, 20–40 × 1–2 mm, margins entire, faces finely hirsute, eglandular;

cauline reduced, restricted to proximal 1/3 of stems.

basal (persistent) and cauline;

basal (purplish) and proximal cauline blades oblanceolate to oblong, 20–40(–90) × 1–3(–5) mm, cauline reduced distally, margins entire, glabrous or sparsely strigose (or hairs loosely spreading), eglandular.

Involucres

5–7 × 8–16 mm.

5–7.5 × 10–15 mm.

Ray florets

mostly 30–60;

corollas usually white, sometimes fading pink, rarely blue, 5–10 mm, laminae loosely coiling.

40–100;

corollas blue to pinkish purple, 7–14 mm, laminae not coiling or reflexing.

Disc corollas

2.8–4 mm.

4.1–5.6 mm.

Phyllaries

in 2–3 series, hirsute to hirsuto-strigose, minutely glandular.

in 2–3(–4) series (margins and tips often purplish, loose, linear-lanceolate, apices spreading), sparsely strigoso-hirsute to strigose (hairs appressed or slightly loose), sometimes minutely glandular.

Heads

1.

1.

Cypselae

1.8–2.2 mm, 2-nerved, faces moderately, loosely strigose;

pappi: outer of setae, inner of 15–25 bristles.

2 mm, 2-nerved, faces sparsely strigose;

pappi: outer of setae, inner of 14–21 bristles.

2n

= 18.

Erigeron disparipilus

Erigeron gracilis

Phenology Flowering May–Aug. Flowering Jun–Aug.
Habitat Gravelly and rocky slopes, ridges, sagebrush, grassland Moist slopes, creek bottoms, sagebrush meadows
Elevation 600–2000(–2200) m [2000–6600(–7200) ft] 2200–2400 m [7200–7900 ft]
Distribution
from FNA
ID; OR; WA
[WildflowerSearch map]
[BONAP county map]
from FNA
ID; MT; WY
[WildflowerSearch map]
[BONAP county map]
Discussion

Erigeron disparipilus is similar to E. nanus but less variable. The range of E. disparipilus barely contacts that of E. nanus in southeastern Idaho and they have different ecologies; blue rays of E. disparipilus in Owyhee County may indicate that hybridization occurs.

(Discussion copyrighted by Flora of North America; reprinted with permission.)

Erigeron gracilis “differs from E. ursinus in the strigose and scarcely glandular pubescence of the involucre, narrower and less herbaceous phyllaries, narrower and on the average longer disc-corollas, simple or nearly simple pappus, narrower ligules, on the average, and ordinarily narrower and slightly hairier leaves. E. gracilis grows at lower elevations than E. ursinus, in a drier habitat, and has a much more restricted range” (A. Cronquist 1947, p. 162). The two species are sympatric in northwestern Wyoming.

(Discussion copyrighted by Flora of North America; reprinted with permission.)

Parent taxa Asteraceae > tribe Astereae > Erigeron Asteraceae > tribe Astereae > Erigeron
Sibling taxa
E. abajoensis, E. acomanus, E. acris, E. aequifolius, E. algidus, E. aliceae, E. allocotus, E. alpiniformis, E. anchana, E. annuus, E. aphanactis, E. arenarioides, E. argentatus, E. arisolius, E. arizonicus, E. asperugineus, E. aureus, E. barbellulatus, E. basalticus, E. bellidiastrum, E. bigelovii, E. biolettii, E. blochmaniae, E. bloomeri, E. breweri, E. caespitosus, E. calvus, E. canaani, E. canus, E. cascadensis, E. cavernensis, E. cervinus, E. chrysopsidis, E. clokeyi, E. compactus, E. compositus, E. concinnus, E. consimilis, E. corymbosus, E. coulteri, E. cronquistii, E. davisii, E. decumbens, E. denalii, E. divergens, E. eatonii, E. elatior, E. elatus, E. elegantulus, E. elmeri, E. engelmannii, E. evermannii, E. eximius, E. filifolius, E. flabellifolius, E. flagellaris, E. flettii, E. foliosus, E. formosissimus, E. garrettii, E. geiseri, E. glabellus, E. glacialis, E. glaucus, E. goodrichii, E. gracilis, E. grandiflorus, E. greenei, E. heliographis, E. hessii, E. howellii, E. humilis, E. hyperboreus, E. hyssopifolius, E. inornatus, E. jonesii, E. kachinensis, E. karvinskianus, E. klamathensis, E. kuschei, E. lackschewitzii, E. lanatus, E. lassenianus, E. latus, E. leibergii, E. leiomerus, E. lemmonii, E. linearis, E. lobatus, E. lonchophyllus, E. maguirei, E. mancus, E. maniopotamicus, E. mariposanus, E. melanocephalus, E. miser, E. modestus, E. muirii, E. multiceps, E. nanus, E. nauseosus, E. nematophyllus, E. neomexicanus, E. nivalis, E. ochroleucus, E. oreganus, E. oreophilus, E. ovinus, E. oxyphyllus, E. pallens, E. parishii, E. parryi, E. peregrinus, E. petrophilus, E. philadelphicus, E. pinnatisectus, E. piperianus, E. piscaticus, E. poliospermus, E. porsildii, E. pringlei, E. procumbens, E. pulchellus, E. pulcherrimus, E. pumilus, E. purpuratus, E. pygmaeus, E. quercifolius, E. radicatus, E. reductus, E. religiosus, E. rhizomatus, E. robustior, E. rybius, E. rydbergii, E. salishii, E. salmonensis, E. sanctarum, E. saxatilis, E. sceptrifer, E. scopulinus, E. serpentinus, E. sionis, E. sivinskii, E. sparsifolius, E. speciosus, E. strigosus, E. subglaber, E. subtrinervis, E. supplex, E. tenellus, E. tener, E. tenuis, E. tracyi, E. trifidus, E. tweedyi, E. uintahensis, E. uncialis, E. uniflorus, E. untermannii, E. ursinus, E. utahensis, E. vagus, E. velutipes, E. vernus, E. versicolor, E. vetensis, E. vicinus, E. vreelandii, E. watsonii, E. wilkenii, E. yukonensis
E. abajoensis, E. acomanus, E. acris, E. aequifolius, E. algidus, E. aliceae, E. allocotus, E. alpiniformis, E. anchana, E. annuus, E. aphanactis, E. arenarioides, E. argentatus, E. arisolius, E. arizonicus, E. asperugineus, E. aureus, E. barbellulatus, E. basalticus, E. bellidiastrum, E. bigelovii, E. biolettii, E. blochmaniae, E. bloomeri, E. breweri, E. caespitosus, E. calvus, E. canaani, E. canus, E. cascadensis, E. cavernensis, E. cervinus, E. chrysopsidis, E. clokeyi, E. compactus, E. compositus, E. concinnus, E. consimilis, E. corymbosus, E. coulteri, E. cronquistii, E. davisii, E. decumbens, E. denalii, E. disparipilus, E. divergens, E. eatonii, E. elatior, E. elatus, E. elegantulus, E. elmeri, E. engelmannii, E. evermannii, E. eximius, E. filifolius, E. flabellifolius, E. flagellaris, E. flettii, E. foliosus, E. formosissimus, E. garrettii, E. geiseri, E. glabellus, E. glacialis, E. glaucus, E. goodrichii, E. grandiflorus, E. greenei, E. heliographis, E. hessii, E. howellii, E. humilis, E. hyperboreus, E. hyssopifolius, E. inornatus, E. jonesii, E. kachinensis, E. karvinskianus, E. klamathensis, E. kuschei, E. lackschewitzii, E. lanatus, E. lassenianus, E. latus, E. leibergii, E. leiomerus, E. lemmonii, E. linearis, E. lobatus, E. lonchophyllus, E. maguirei, E. mancus, E. maniopotamicus, E. mariposanus, E. melanocephalus, E. miser, E. modestus, E. muirii, E. multiceps, E. nanus, E. nauseosus, E. nematophyllus, E. neomexicanus, E. nivalis, E. ochroleucus, E. oreganus, E. oreophilus, E. ovinus, E. oxyphyllus, E. pallens, E. parishii, E. parryi, E. peregrinus, E. petrophilus, E. philadelphicus, E. pinnatisectus, E. piperianus, E. piscaticus, E. poliospermus, E. porsildii, E. pringlei, E. procumbens, E. pulchellus, E. pulcherrimus, E. pumilus, E. purpuratus, E. pygmaeus, E. quercifolius, E. radicatus, E. reductus, E. religiosus, E. rhizomatus, E. robustior, E. rybius, E. rydbergii, E. salishii, E. salmonensis, E. sanctarum, E. saxatilis, E. sceptrifer, E. scopulinus, E. serpentinus, E. sionis, E. sivinskii, E. sparsifolius, E. speciosus, E. strigosus, E. subglaber, E. subtrinervis, E. supplex, E. tenellus, E. tener, E. tenuis, E. tracyi, E. trifidus, E. tweedyi, E. uintahensis, E. uncialis, E. uniflorus, E. untermannii, E. ursinus, E. utahensis, E. vagus, E. velutipes, E. vernus, E. versicolor, E. vetensis, E. vicinus, E. vreelandii, E. watsonii, E. wilkenii, E. yukonensis
Synonyms E. ursinus var. gracilis
Name authority Cronquist: Brittonia 6: 194. (1947) Rydberg: Mem. New York Bot. Gard. 1: 404. (1900)
Source FNA vol. 20, p. 285. Treatment author: Guy L. Nesom. FNA vol. 20, p. 336. Treatment author: Guy L. Nesom.
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