Erigeron caespitosus |
Erigeron denalii |
|
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tuft daisy, tuft fleabane |
Denali fleabane |
|
Habit | Perennials, 5–25(–30) cm; taprooted, caudices relatively thick, usually branched. | Perennials, 1–5 cm; taprooted, caudices diffuse with extensive systems of rhizomelike, relatively long and slender branches. |
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 (simple, ± scapiform), villous, granular-glandular. |
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 (persistent) and cauline; blades spatulate to oblanceolate-spatulate, 10–20 × 2–4(–5) mm, mid larger than basal and proximal, margins entire or shallowly (2–)3-lobed or -toothed apically (apices obtuse to nearly truncate), faces moderately villous, minutely glandular. |
Involucres | 4–7 × 9–18 mm. |
(4–)5–7 × 9–12 mm. |
Ray florets | 30–100; corollas white to bluish, 5–15 mm, laminae coiling. |
30–55; corollas white to lavender, 4–8 mm, laminae (filiform to narrowly straplike, 0.3–2 mm wide, often involute) erect, rarely spreading, not coiling or reflexing. |
Disc florets/ |
3–4.4 mm. |
3.8–4.8 mm. |
Phyllaries | in 3–4 series, densely hirsuto-canescent to hirtellous (hairs spreading), moderately minutely glandular. |
in 2(–3) series, densely lanate-villous (hairs to 3 mm, often with dark purple cross walls), glandular. |
Heads | 1–4 (branches from distal 1/2 of stem). |
1. |
Cypselae | 1.7–2.2 mm, 2-nerved, faces sparsely strigose; pappi: outer of setae or scales, inner of 15–25 bristles. |
3–3.8 mm, 2-nerved, faces strigillose to strigoso-hirsute; pappi: outer 0 (or inconspicuous), inner of 20–25 (usually ± purple-red tinged, sometimes whitish, variable within populations) bristles. |
2n | = 18, 36. |
|
Erigeron caespitosus |
Erigeron denalii |
|
Phenology | Flowering Jun–Aug. | Flowering Jun–Aug. |
Habitat | Rocky or sandy, grassy hills, sagebrush-aspen, pinyon-juniper, to spruce and tundra northward | Open alpine and subalpine habitats, tundra slopes, openings in spruce-fir woods, gravelly and shaley scree, cut banks |
Elevation | 1300–3000(–3600) m (4300–9800(–11800) ft) | 900–2200 m (3000–7200 ft) |
Distribution |
AK; AZ; CO; ID; MT; ND; NE; NM; SD; UT; WA; WY; AB; BC; MB; SK; YT
|
AK; NT; YT; BC |
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.) |
Erigeron denalii and E. purpuratus are similar and probably closely related; the two appear to be partially sympatric; differences in vestiture and leaf morphology are constant. The habitat of E. purpuratus, sandy or gravelly alluvium, also is remarkably constant and distinct from that of E. denalii. Apparently correlated with the habitat, plants of E. purpuratus almost always develop a relatively long and slender, woody taproot; taproots of E. denalii apparently are less well defined and often are not collected. Plants of the type collection of Erigeron mexiae have ray corollas with relatively broad laminae (1.5–2 mm wide); ray corolla width is variable in E. denalii, and E. mexiae is regarded here as an extreme variant within the species. In other characters, there appears to be no difference. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Source | FNA vol. 20, p. 283. | FNA vol. 20, p. 303. |
Parent taxa | Asteraceae > tribe Astereae > Erigeron | Asteraceae > tribe Astereae > Erigeron |
Sibling taxa | ||
Synonyms | E. mexiae, E. purpuratus var. dilatatus | |
Name authority | Nuttall: Trans. Amer. Philos. Soc., n. s. 7: 307. (1840) | A. Nelson: Amer. J. Bot. 32: 289. (1945) |
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