Erigeron caespitosus |
Erigeron engelmannii |
|
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tuft daisy, tuft fleabane |
Engelmann's fleabane |
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Habit | Perennials, 5–25(–30) cm; taprooted, caudices relatively thick, usually branched. | Perennials, 3–20(–30) cm; taprooted, caudex branches relatively short and thick. |
Stems | decumbent-ascending (greenish proximally), usually densely hirsute to hirtellous (hairs spreading to deflexed, gradually attenuate, basal cells erect), sometimes strigose (in Saskatchewan and Yukon), 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 blades (1–)3-nerved, narrowly oblanceolate to spatulate, (10–)20–90(–120) × 2–15 mm, margins entire (apices rounded to obtuse), faces densely hirtellous, eglandular; cauline blades oblong-ovate to linear, ± 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 | 4–7 × 9–18 mm. |
3.5–5(–6) × 7–12 mm. |
Ray florets | 30–100; corollas white to bluish, 5–15 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 | 3–4.4 mm. |
(2.5–)2.7–4.2 mm (throats indurate and inflated, densely puberulent). |
Phyllaries | in 3–4 series, densely hirsuto-canescent to hirtellous (hairs spreading), moderately minutely glandular. |
in 2–3(–4) series, coarsely hirsuto-villous, sparsely to moderately minutely glandular. |
Heads | 1–4 (branches from distal 1/2 of stem). |
1(–3). |
Cypselae | 1.7–2.2 mm, 2-nerved, faces sparsely strigose; pappi: outer of setae or scales, inner of 15–25 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. |
2n | = 18, 36. |
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Erigeron caespitosus |
Erigeron engelmannii |
|
Phenology | Flowering Jun–Aug. | Flowering (Apr–)May–Jul. |
Habitat | Rocky or sandy, grassy hills, sagebrush-aspen, pinyon-juniper, to spruce and tundra northward | Dry, sandy or rocky sites, prairies, often with sagebrush, rabbitbrush, juniper, pinyon-juniper, salt desert shrub |
Elevation | 1300–3000(–3600) m (4300–9800(–11800) ft) | 1300–2500 m (4300–8200 ft) |
Distribution |
AK; AZ; CO; ID; MT; ND; NE; NM; SD; UT; WA; WY; AB; BC; MB; SK; YT
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CO; ID; UT; WY
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Discussion | Erigeron caespitosus as recognized here is highly variable and perhaps justifiably could be divided into more than one taxon. Plants at lower elevations tend to produce tall stems branching above the middle and long, white rays. At higher elevations, especially in Idaho, western Montana, Utah, and Wyoming, stems tend to be shorter and simple and the rays commonly are blue to violet. In the Bitterroot Mountains (Ravalli and Deerlodge counties, Montana), short-stemmed, blue-rayed plants also have strigose cauline vestiture (in contrast to typically deflexed-hirtellous stems); these vestiture variants occur in the same area with plants apparently similar in all other features. Strigose populational variants also occur in Saskatchewan and Yukon, and E. abajoensis, largely distinguished by strigose cauline vestiture, might be considered a regional variant of E. caespitosus. In eastern Idaho and southwestern Montana, plants of E. caespitosus are commonly encountered with cauline leaves obovate and distinctly subclasping. Plants with strongly 3-nerved basal leaves occur in Carbon and Gallatin counties, Montana. (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. 283. | FNA vol. 20, p. 290. |
Parent taxa | Asteraceae > tribe Astereae > Erigeron | Asteraceae > tribe Astereae > Erigeron |
Sibling taxa | ||
Name authority | Nuttall: Trans. Amer. Philos. Soc., n. s. 7: 307. (1840) | A. Nelson: Bull. Torrey Bot. Club 26: 247. (1899) |
Web links |