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three-vein fleabane, threenerve fleabane

Porsild's arctic fleabane

Habit Perennials, 15–90 cm; rhizomatous to subrhizomatous, fibrous-rooted, caudices usually branched, woody, thick. Perennials, (2–)10–20(–25) cm; rhizomatous, fibrous-rooted, rhizomes horizontal or erect, sometimes branched, relatively short, sometimes resembling taproots.
Stems

erect, moderately to densely hirsute (hairs 0.5–0.8 mm), eglandular.

erect, sparsely to moderately villous (hairs 0.5–1.6 mm), usually stipitate-glandular (hairs 0.05–0.4 mm).

Leaves

basal (usually withering by flowering) and cauline;

basal blades oblanceolate-spatulate, 30–80 × 6–20(–27) mm, margins entire, faces evenly hirsute to strigoso-hirsute, usually eglandular;

cauline blades lanceolate to oblong, oblong-ovate, or broadly ovate, nearly even-sized distally or sometimes mid largest (continuing to immediately proximal to heads, bases clasping to subclasping).

basal (persistent) and cauline;

basal blades oblong-oblanceolate to narrowly obovate, 30–120 × (3–)5–14 mm, margins entire (apices acute), faces densely hirsute to coarsely villous, sparsely stipitate-glandular to minutely glandular;

cauline blades oblong-lanceolate to lanceolate, gradually reduced distally or nearly equal-sized (bases often subclasping).

Involucres

6–9 × 13–20 mm.

6–10 × 12–20 mm.

Ray florets

100–150;

corollas blue to lavender, 7–18 mm (ca. 1 mm wide), laminae coiling at tips.

65–110;

corollas white to lavender or blue, 13–17 mm (1.2–1.7 mm wide), laminae weakly coiling.

Disc corollas

4–5 mm.

3.8–4.5 mm.

Phyllaries

in 2–3(–4) series, moderately to densely hirsute, minutely glandular.

in ca. 2 series (purple at least at tips, narrowly lanceolate, equal, apically acuminate), densely hirsute, hirsuto-villous, or villous (hairs whitish, cross walls not colored), sparsely stipitate-glandular to minutely glandular.

Heads

1–6(–21) in corymbiform arrays.

1.

Cypselae

1.6–2 mm, 2(–4)-nerved, faces sparsely strigose;

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

2–2.5 mm, 2-nerved, faces sparsely strigose;

pappi: outer of relatively long setae or scales, inner of 14–20(–25) bristles.

2n

= 36.

Erigeron subtrinervis

Erigeron porsildii

Phenology Flowering (Jun–)Jul–Sep. Flowering (Jun–)Jul–Aug(–Sep).
Habitat Opening and margins, roadsides, often shaded, ponderosa pine, pine-fir, mixed conifer, aspen Cliffs and talus (often calcareous) slopes, shaley gravel, grassy ravines, dry tundra
Elevation 1800–3000(–3500) m (5900–9800(–11500) ft) 600–2100 m (2000–6900 ft)
Distribution
from FNA
CO; ID; MT; ND; NE; NM; SD; UT; WY
[WildflowerSearch map]
[BONAP county map]
from FNA
AK; NT; YT
[BONAP county map]
Discussion

Erigeron subtrinervis is variable in vestiture, perhaps reflecting gene exchange with E. speciosus. Erigeron speciosus var. mollis (A. Gray) S. L. Welsh may be a recurrent hybrid; it is identified here within E. subtrinervis.

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

Erigeron hultenii S. A. Spongberg was noted to be “closely allied to the polymorphic arctic-alpine species E. grandiflorus W. J. Hooker” (S. A. Spongberg 1973, p. 116) and to have a “close morphologic resemblance to some plants of E. grandiflorus from Alaska” [E. porsildii in the present sense] (p. 119). Plants corresponding to E. hultenii have not been recollected, and that taxon does not fit with any other known Alaskan species. Contrasts with E. porsildii exclude it from that species. Erigeron hultenii is not recognized formally herein.

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

Source FNA vol. 20, p. 330. FNA vol. 20, p. 324.
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. 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. 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. glabellus var. mollis, E. speciosus var. mollis E. grandiflorus subsp. arcticus
Name authority Rydberg ex Porter & Britton: Mem. Torrey Bot. Club 5: 328. (1894) G. L. Nesom & D. F. Murray: Sida 21: 44. (2004)
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