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Tweedy's fleabane

Willamette fleabane, Willamette Valley daisy

Habit Perennials, 4–20 cm; taprooted, caudices multicipital crowns or branches relatively short and thick. Perennials, 5–60 cm (colonial); taprooted, caudex branches rhizomelike plants.
Stems

erect to ascending or decumbent-prostrate, densely strigose (hairs relatively thin), eglandular.

(often purplish) erect or decumbent at bases, sparsely strigillose (basal cells inclined, hairs even-width), eglandular.

Leaves

basal (persistent) and cauline;

basal (silvery) blades spatulate, broadly elliptic, 50–250 × 5–13 mm, cauline abruptly reduced distally, margins entire, faces densely strigoso-sericeous (hairs gray-white), eglandular.

basal (often withering by flowering) and cauline;

basal blades linear to narrowly oblanceolate, 50–120(–180) × 3–6(–11) mm;

cauline 3-nerved, gradually reduced distally, margins entire, faces hirtellous, eglandular.

Involucres

4–6 × 9–14 mm.

(4.5–)5–6 × 9–12 mm.

Ray florets

20–50;

corollas blue to purple, sometimes white, 5–9 mm, laminae not coiling or reflexing.

26–57;

corollas white to bluish, sometimes drying pinkish to pale blue, 7–12 mm, laminae not coiling or reflexing.

Disc corollas

3.1–4.3 mm.

3–3.5 mm.

Phyllaries

in 3–4 series, finely hirsuto-strigose, sparsely minutely glandular.

in 2–3(–4) series (linear-lanceolate, apices linear-acuminate), sparsely to moderately villous, eglandular.

Heads

1–4.

(1–)2–5(–18) borne singly or in loosely corymbiform arrays.

Cypselae

2–2.5 mm, 2-nerved, faces strigoso-sericeous;

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

1.2–1.6 mm, 2-nerved, faces sparsely strigose;

pappi: outer of setae, inner of (6–)12–16 bristles.

Erigeron tweedyi

Erigeron decumbens

Phenology Flowering Jun–Aug. Flowering May–Jul.
Habitat Clay hills, rocky slopes, limestone taluses, shale outcrops, sagebrush-grasslands Heavy soils in seasonally wet or dry upland prairie grasslands
Elevation (1300–)1600–3000 m ((4300–)5200–9800 ft) 100–300 m (300–1000 ft)
Distribution
from FNA
ID; MT; WY
[WildflowerSearch map]
[BONAP county map]
from FNA
OR
[WildflowerSearch map]
[BONAP county map]
Discussion

Of conservation concern.

Erigeron decumbens is in the Center for Plant Conservation’s National Collection of Endangered Plants.

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

Source FNA vol. 20, p. 304. FNA vol. 20, p. 279.
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. 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. 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. 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
Name authority Canby: Bot. Gaz. 13: 17. (1888) Nuttall: Trans. Amer. Philos. Soc., n. s. 7: 309. (1840)
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