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Erigeron disparipilus

Snake River daisy, Snake River fleabane, white cushion fleabane

bitter daisy, bitter fleabane, northern daisy, snow fleabane, snow fleabane daisy, snowbed fleabane

Habit Perennials, 3–12 cm; taprooted, caudices branched. Biennials or short-lived perennials, 5–25(–35) cm; usually fibrous-rooted, sometimes taprooted, caudices simple or branched, sometimes weakly short-rhizomatous.
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.

erect to basally ascending, sometimes sparsely hirsuto-villous, minutely glandular.

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 (petiole margins coarsely ciliate);

basal blades oblanceolate to spatulate, 20–60 × 2–6(–10) mm;

cauline gradually reduced distally, margins entire or rarely with 1–2 pairs of shallow teeth, faces sparsely hirsuto-strigose, eglandular.

Involucres

5–7 × 8–16 mm.

5–6 × 8–11 mm.

Ray florets

mostly 30–60;

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

Ray (pistillate) florets

in 2 series;

outer 40–70, corollas white to pinkish 5.5–7 mm, laminae (filiform) erect, not coiling or reflexing;

inner many fewer than outer series, tubular, elaminate.

Disc corollas

2.8–4 mm.

4.4–5.5 mm.

Phyllaries

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

in 2–3(–4) series (inner apices attenuate to caudate), sparsely hirsuto-villous or glabrous, minutely glandular.

Heads

1.

1–6(–8) in corymbiform arrays (on curved-ascending peduncles).

Cypselae

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

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

2–2.3 mm, 2-nerved, faces sparsely strigose;

pappi: outer of setae, inner of (12–)14–21 (accrescent) bristles.

2n

= 18.

Erigeron disparipilus

Erigeron nivalis

Phenology Flowering May–Aug. Flowering May–Aug.
Habitat Gravelly and rocky slopes, ridges, sagebrush, grassland Rocky sites, gravel bars and banks, roadsides, meadows, open woods, up to subalpine areas with spruce in Rocky Mountains
Elevation 600–2000(–2200) m [2000–6600(–7200) ft] 1200–3700 m [3900–12100 ft]
Distribution
from FNA
ID; OR; WA
[WildflowerSearch map]
[BONAP county map]
from FNA
AK; CA; CO; ID; MT; NM; OR; UT; WA; WY; AB; BC; NT; YT
[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 nivalis usually has been treated as an infra-specific taxon within E. acris; the two are broadly sympatric in the northwestern United States and Canada without obvious intergrades. Both occur over a wide range of elevations and in similar habitats. Erigeron nivalis probably occurs in Nevada; it has not been taxonomically distinguished there. Erigeron scotteri was regarded by E. H. Moss and J. G. Packer (1983) as a synonym of E. acris (presumably var. debilis = E. nivalis; the heads are relatively small and borne singly).

(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. 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. 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. acris subsp. debilis, E. acris var. debilis, E. angulosus subsp. debilis, E. debilis, E. elatus var. bakeri, E. jucundus, E. scotteri, Trimorpha acris var. debilis
Name authority Cronquist: Brittonia 6: 194. (1947) Nuttall: Trans. Amer. Philos. Soc., n. s. 7: 311. (1841)
Source FNA vol. 20, p. 285. Treatment author: Guy L. Nesom. FNA vol. 20, p. 322. Treatment author: Guy L. Nesom.
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