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

branch fleabane, branching daisy, club-fruit willowherb, common eastern fleabane, daisy fleabane, plains fleabane, prairie fleabane, purple-leaf willowherb, rough fleabane, rough-stem daisy, rough-stem fleabane, vergerette rude, whitetop fleabane

Habit Perennials, 10–30(–50) cm; taprooted, caudices multicipital, often with relatively short and thin, stemlike, lignescent branches. Annuals, biennials, or short-lived perennials, 30–70 cm; fibrous-rooted, caudices simple, sometimes lignescent, sometimes producing rhizomes that bear leaf tufts at upturned ends.
Stems

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

erect or ascending, sparsely to moderately strigose to strigillose or hirsuto-strigillose (hairs usually ascending, rarely spreading, 0.1–1.2 mm), eglandular.

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.

basal (usually persistent through flowering) and cauline;

basal blades spatulate to broadly or narrowly oblanceolate to linear, (10–)30–150(–170) × 5–15(–21) mm;

cauline usually gradually reduced distally, continuing to near heads, margins entire or shallowly to deeply serrate or crenate, faces glabrous or glabrate to sparsely strigose or strigoso-hirsute, eglandular.

Involucres

4–7 × 5–-18 mm.

(2–)3–4 × 5–12 mm.

Ray florets

(15–)20–125;

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

50–100;

corollas white, less commonly pinkish or bluish, 4–6 mm, laminae coiling.

Disc corollas

2.5–5.5 mm.

1.5–2.5 mm (throats sometimes slightly indurate and inflated).

Phyllaries

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

in 2–4 series, glabrous, strigose, or sparsely hirsute, sometimes minutely glandular.

Heads

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

10–200+ in loosely corymbiform to paniculiform-corymbiform arrays (on distal branches).

Cypselae

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

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

(0.5–)0.9–1.2 mm, 2-nerved, faces sparsely strigose;

pappi: outer crowns of setae or scales, inner 0 (rays) or of 8–15 bristles (disc).

2n

= 18.

Erigeron filifolius

Erigeron strigosus

Phenology Flowering May–Aug.
Habitat Dry, rocky or sandy soil, lava beds, bitterbrush, sagebrush, juniper, ponderosa pine
Elevation 400–2400 m (1300–7900 ft)
Distribution
from FNA
CA; ID; MT; NV; OR; UT; WA; BC
[WildflowerSearch map]
[BONAP county map]
from FNA
AL; AR; CA; CO; CT; DC; DE; FL; GA; IA; ID; IL; IN; KS; KY; LA; MA; MD; ME; MI; MN; MO; MS; MT; NC; ND; NE; NH; NJ; NM; NY; OH; OK; OR; PA; RI; SC; SD; TN; TX; VA; VT; WA; WI; WV; WY; AB; BC; MB; NB; NF; NS; ON; PE; QC; SK [Introduced in Europe, Pacific Islands (Hawaii)]
[WildflowerSearch map]
[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.)

Varieties 4 (4 in the flora).

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

Key
1. Phyllary hairs flattened, 0.5–1.2 mm; stem hairs appressed to spreading, 0.5–1 mm
var. septentrionalis
1. Phyllary hairs terete, mostly 0.1–0.5 mm; stem hairs appressed to ascending, 0.1–0.4(–0.8) mm
→ 2
2. Annual or rarely biennial, without rhizomes; various habitats, often ruderal
var. strigosus
2. Plants usually perennial (sometimes killed prematurely by severe drought), with rhizomes that bear overwintering leaf tufts at upturned ends; shallow soils over calcareous rock
→ 3
3. Basal leaves linear to linear-oblanceolate, 1–3.5(–6) mm wide; cauline leaf faces sparsely to moderately strigillose
var. dolomiticola
3. Basal leaves oblanceolate to narrowly obovate or spatulate, (3.2–)3.8–15(–21) mm wide; cauline leaf faces glabrous, margins and midveins ciliate
var. calcicola
Source FNA vol. 20, p. 298. FNA vol. 20, p. 345.
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. 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. 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. 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
Subordinate taxa
E. strigosus var. calcicola, E. strigosus var. dolomiticola, E. strigosus var. septentrionalis, E. strigosus var. strigosus
Synonyms Diplopappus filifolius, E. filifolius var. robustior E. annuus subsp. strigosus
Name authority (Hooker) Nuttall: Trans. Amer. Philos. Soc., n. s. 7: 308. (1840) Muhlenberg ex Willdenow: Sp. Pl. 3: 1956. (1803)
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