Erigeron radicatus |
Erigeron engelmannii |
|
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Hooker's fleabane, Huber's fleabane, tap-root fleabane |
Engelmann's fleabane |
|
Habit | Perennials, (1–)2–6(–12) cm; taprooted, caudices branches relatively short, thick. | Perennials, 3–20(–30) cm; taprooted, caudex branches relatively short and thick. |
Stems | erect, strigose to sparsely or densely short-villous (hairs loosely appressed to ascending or spreading), eglandular. |
erect, loosely to closely, sparsely to moderately strigose (hairs 0.1–0.9 mm), usually minutely glandular (glands barely evident), sometimes eglandular. |
Leaves | mostly basal (persistent) (eciliate or weakly ciliate proximally); blades 1-nerved linear to narrowly oblanceolate or subspatulate, (5–)10–50(–60) × 0.8–2.5 mm (bases gradually narrowing), margins entire (apices obtuse to rounded), abaxial faces glabrate or glabrous, shiny, adaxial sparsely, loosely strigose, eglandular; cauline mostly on proximal 1/2–1/3 of stems (absent in some high elevation forms), abruptly or gradually reduced distally. |
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 | (3–)4–6(–8) × (5–)8–12(–15) mm. |
3.5–5(–6) × 7–12 mm. |
Ray florets | (12–)20–44(–85); corollas white, less commonly purplish, 4–7(–8) mm, laminae coiling. |
(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 | (2–)2.5–3.5(–4) mm. |
(2.5–)2.7–4.2 mm (throats indurate and inflated, densely puberulent). |
Phyllaries | in 2–3(–4) series (subequal), villosulous to villoso-hirsutulous (hairs usually with purplish cross walls at least in basal cells), minutely glandular apically or eglandular. |
in 2–3(–4) series, coarsely hirsuto-villous, sparsely to moderately minutely glandular. |
Heads | 1. |
1(–3). |
Cypselae | 2.1–2.5 mm, 2-nerved, faces sparsely strigose; pappi: outer of scales, inner of (6–)7–11 (readily falling) 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 radicatus |
Erigeron engelmannii |
|
Phenology | Flowering May–Aug. | Flowering (Apr–)May–Jul. |
Habitat | Rocky slopes, ridges, and summits, ledges and crevices, outcrops and talus, usually limestone, alpine tundra | Dry, sandy or rocky sites, prairies, often with sagebrush, rabbitbrush, juniper, pinyon-juniper, salt desert shrub |
Elevation | (1400–)1600–2800(–3400) m ((4600–)5200–9200(–11200) ft) | 1300–2500 m (4300–8200 ft) |
Distribution |
CO; ID; MT; ND; NE; SD; UT; WY; AB; SK
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CO; ID; UT; WY
|
Discussion | Collections of Erigeron radicatus often have been identified as E. ochroleucus var. scribneri; E. radicatus is distinctive in its branched caudex, villous cauline vestiture, more reduced leaf vestiture, involucral vestiture of hairs with purple cross walls, shorter disc corollas, and relatively few, readily falling pappus bristles. Erigeron radicatus often is essentially scapiform at relatively high elevation (2700–3400 m) in Idaho, Montana, Utah, and Wyoming; more eastern populations in the Great Plains, at lower elevations (1400–2600 m), have leafier stems but are hardly different in other features. Plants of some populations in Albany and Carbon counties, Wyoming, produce atypically shorter rays. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
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. 294. | FNA vol. 20, p. 290. |
Parent taxa | Asteraceae > tribe Astereae > Erigeron | Asteraceae > tribe Astereae > Erigeron |
Sibling taxa | ||
Synonyms | E. huberi, E. macounii | |
Name authority | Hooker: Fl. Bor.-Amer. 2: 17, plate 122. (1834) | A. Nelson: Bull. Torrey Bot. Club 26: 247. (1899) |
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