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Peck's threadleaf fleabane, thread-leaf daisy, thread-leaf fleabane

arid throne fleabane, dry-sun fleabane

Habit Perennials, 10–30(–50) cm; taprooted, caudices multicipital, often with relatively short and thin, stemlike, lignescent branches. Annuals or short-lived perennials, 30–70 cm; taprooted.
Stems

erect, sparsely to densely strigose (hairs loosely appressed to ascending, fine), densely white-strigose at least proximally, eglandular.

erect, coarsely hirsute to hispid (hairs only along ribs, bases thickened), minutely glandular.

Leaves

basal (usually persistent, not clustered as rosettes) and cauline;

basal blades linear to filiform, 10–80 × 0.5–2.5(–3.5) mm;

cauline gradually or little reduced distally, margins entire, faces sparsely to moderately strigose, eglandular.

mostly cauline;

blades linear to linear-oblong, -lanceolate, or -oblanceolate (slightly narrowed distally), 25–50 × 2–5 mm, margins entire or sometimes lobed (lobes 1–2 pairs, coarse, rounded), faces hispido-strigose.

Involucres

4–7 × 5–-18 mm.

2.5–3.5 × 5–8 mm.

Ray florets

(15–)20–125;

corollas usually blue, sometimes white, pink, or pale lavender, 3–13 mm, laminae coiling.

125–180;

corollas usually white, sometimes lavender or pinkish, 6–7 mm, laminae reflexing.

Disc corollas

2.5–5.5 mm.

2–2.5 mm (throats indurate and inflated).

Phyllaries

in (2–)3–4 series, loosely strigose to hirsute or nearly villous, densely to sparsely minutely glandular.

in 3–4 series, minutely hispid, minutely glandular.

Heads

1–5(–10+) from distal branches, tending to be in corymbiform arrays.

20–50+ in loose, corymbiform arrays (buds erect).

Cypselae

1.4–1.8(–2) mm, 2-nerved, faces sparsely strigose to glabrate;

pappi: outer of setae, inner of 20–30 bristles.

0.7–1 mm, 2-nerved (nerves orange), faces sparsely strigose to glabrate;

pappi: outer of setae or lanceolate scales, inner of (10–)12–17 bristles.

2n

= 18.

= 18.

Erigeron filifolius

Erigeron arisolius

Phenology Flowering May–Aug. Flowering May–Jun(–Nov).
Habitat Dry, rocky or sandy soil, lava beds, bitterbrush, sagebrush, juniper, ponderosa pine Grasslands, often in moist areas, sometimes with mesquite, openings, roadsides, oak, juniper, mesquite
Elevation 400–2400 m (1300–7900 ft) (800–)1300–1700 m ((2600–)4300–5600 ft)
Distribution
from FNA
CA; ID; MT; NV; OR; UT; WA; BC
[WildflowerSearch map]
[BONAP county map]
from FNA
AZ; Mexico (Sonora)
[BONAP county map]
Discussion

The densely white-strigose stem bases, linear-filiform leaves relatively unreduced distally, and relatively few heads with coiling, usually blue rays are distinctive for Erigeron filifolius. Proximal leaves are not clustered as a basal rosette; they are inserted on closely spaced nodes that are slightly more separated distally. Plants identified as var. robustior (with more ray florets, fewer heads, and thicker stems, centered in Oregon and Washington) intergrade with the typical form and apparently are separated arbitrarily.

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

Of conservation concern.

Erigeron arisolius is similar in general appearance to E. divergens; the erect buds and reflexing rays of E. arisolius contrast with the nodding buds and non-reflexing rays of E. divergens. Additionally, the latter has evenly distributed stem pubescence, cypselae with whitish nerves (versus orange), and fewer pappus bristles. Erigeron sceptrifer also may be difficult to distinguish from these: it is more similar to E. arisolius in vestiture and has shorter rays that usually become purple upon drying and that are downward-curved, compared to those of E. arisolius, where the rays dry a lighter color and reflex at the tube-lamina junction.

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

Source FNA vol. 20, p. 298. FNA vol. 20, p. 337.
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. disparipilus, E. divergens, E. eatonii, E. elatior, E. elatus, E. elegantulus, E. elmeri, E. engelmannii, E. evermannii, E. eximius, 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. 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. 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 Diplopappus filifolius, E. filifolius var. robustior
Name authority (Hooker) Nuttall: Trans. Amer. Philos. Soc., n. s. 7: 308. (1840) G. L. Nesom: Phytologia 69: 243. (1990)
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