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Tweedy's fleabane

Engelmann's fleabane

Habit Perennials, 4–20 cm; taprooted, caudices multicipital crowns or branches relatively short and thick. Perennials, 3–20(–30) cm; taprooted, caudex branches relatively short and thick.
Stems

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

erect, loosely to closely, sparsely to moderately strigose (hairs 0.1–0.9 mm), usually minutely glandular (glands barely evident), sometimes 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 (usually persistent) and cauline (petioles prominently ciliate at least on proximal portions, hairs spreading, thick-based);

basal blades linear-oblanceolate, 20–100 × 1–4 mm, margins entire, faces strigose, eglandular;

cauline usually restricted to proximal 1/2 of stems, slightly reduced distally.

Involucres

4–6 × 9–14 mm.

3.5–5(–6) × 7–12 mm.

Ray florets

20–50;

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

(35–)45–100;

corollas white, sometimes pink or bluish, 5–10 mm, laminae (0.8–1.1 mm wide) primarily reflexing, sometimes also weakly coiling at the tips.

Disc corollas

3.1–4.3 mm.

(2.5–)2.7–4.2 mm (throats indurate and inflated, densely puberulent).

Phyllaries

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

in 2–3(–4) series, coarsely hirsuto-villous, sparsely to moderately minutely glandular.

Heads

1–4.

1(–3).

Cypselae

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

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

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

pappi: outer usually of narrow scales, sometimes 0 or of setae, inner of 12–20 bristles.

Erigeron tweedyi

Erigeron engelmannii

Phenology Flowering Jun–Aug. Flowering (Apr–)May–Jul.
Habitat Clay hills, rocky slopes, limestone taluses, shale outcrops, sagebrush-grasslands Dry, sandy or rocky sites, prairies, often with sagebrush, rabbitbrush, juniper, pinyon-juniper, salt desert shrub
Elevation (1300–)1600–3000 m ((4300–)5200–9800 ft) 1300–2500 m (4300–8200 ft)
Distribution
from FNA
ID; MT; WY
[WildflowerSearch map]
[BONAP county map]
from FNA
CO; ID; UT; WY
[WildflowerSearch map]
[BONAP county map]
Discussion

Plants from Chaffee and Fremont counties, Colorado, have strigose leaves and the compact habit of Erigeron engelmannii but sparsely spreading-hirsute stems; they may be intermediate between E. engelmannii and E. concinnus. Unusual variation in the pappi of E. engelmannii also suggests that the species needs study and better definition.

A. Cronquist observed that “Erigeron engelmannii intergrades completely with E. pumilus, yet has two geographic subspecies of its own, and shows no distributional similarity to the [taxa] of E. pumilus,” and that E. engelmannii is “smaller and more delicate, with shorter finer hairs, and [has] smaller heads with usually fewer ligules.”

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

Source FNA vol. 20, p. 304. FNA vol. 20, p. 290.
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. decumbens, E. denalii, E. disparipilus, E. divergens, E. eatonii, E. elatior, E. elatus, E. elegantulus, E. elmeri, 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) A. Nelson: Bull. Torrey Bot. Club 26: 247. (1899)
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