Erigeron nivalis |
Erigeron caespitosus |
|
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bitter daisy, bitter fleabane, northern daisy, snow fleabane, snow fleabane daisy, snowbed fleabane |
tuft daisy, tuft fleabane |
|
Habit | Biennials or short-lived perennials, 5–25(–35) cm; usually fibrous-rooted, sometimes taprooted, caudices simple or branched, sometimes weakly short-rhizomatous. | Perennials, 5–25(–30) cm; taprooted, caudices relatively thick, usually branched. |
Stems | erect to basally ascending, sometimes sparsely hirsuto-villous, minutely glandular. |
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. |
Leaves | basal (persistent) and cauline (petiole margins coarsely ciliate); basal blades oblanceolate to spatulate, 20–60 × 2–6(–10) mm; cauline gradually reduced distally, margins entire or rarely with 1–2 pairs of shallow teeth, faces sparsely hirsuto-strigose, eglandular. |
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. |
Involucres | 5–6 × 8–11 mm. |
4–7 × 9–18 mm. |
Ray florets | 30–100; corollas white to bluish, 5–15 mm, laminae coiling. |
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Ray (pistillate) florets | in 2 series; outer 40–70, corollas white to pinkish 5.5–7 mm, laminae (filiform) erect, not coiling or reflexing; inner many fewer than outer series, tubular, elaminate. |
|
Disc corollas | 4.4–5.5 mm. |
3–4.4 mm. |
Phyllaries | in 2–3(–4) series (inner apices attenuate to caudate), sparsely hirsuto-villous or glabrous, minutely glandular. |
in 3–4 series, densely hirsuto-canescent to hirtellous (hairs spreading), moderately minutely glandular. |
Heads | 1–6(–8) in corymbiform arrays (on curved-ascending peduncles). |
1–4 (branches from distal 1/2 of stem). |
Cypselae | 2–2.3 mm, 2-nerved, faces sparsely strigose; pappi: outer of setae, inner of (12–)14–21 (accrescent) bristles. |
1.7–2.2 mm, 2-nerved, faces sparsely strigose; pappi: outer of setae or scales, inner of 15–25 bristles. |
2n | = 18. |
= 18, 36. |
Erigeron nivalis |
Erigeron caespitosus |
|
Phenology | Flowering May–Aug. | Flowering Jun–Aug. |
Habitat | Rocky sites, gravel bars and banks, roadsides, meadows, open woods, up to subalpine areas with spruce in Rocky Mountains | Rocky or sandy, grassy hills, sagebrush-aspen, pinyon-juniper, to spruce and tundra northward |
Elevation | 1200–3700 m (3900–12100 ft) | 1300–3000(–3600) m (4300–9800(–11800) ft) |
Distribution |
AK; CA; CO; ID; MT; NM; OR; UT; WA; WY; AB; BC; NT; YT
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AK; AZ; CO; ID; MT; ND; NE; NM; SD; UT; WA; WY; AB; BC; MB; SK; YT
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Discussion | Erigeron nivalis usually has been treated as an infra-specific taxon within E. acris; the two are broadly sympatric in the northwestern United States and Canada without obvious intergrades. Both occur over a wide range of elevations and in similar habitats. Erigeron nivalis probably occurs in Nevada; it has not been taxonomically distinguished there. Erigeron scotteri was regarded by E. H. Moss and J. G. Packer (1983) as a synonym of E. acris (presumably var. debilis = E. nivalis; the heads are relatively small and borne singly). (Discussion copyrighted by Flora of North America; reprinted with permission.) |
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.) |
Source | FNA vol. 20, p. 322. | FNA vol. 20, p. 283. |
Parent taxa | Asteraceae > tribe Astereae > Erigeron | Asteraceae > tribe Astereae > Erigeron |
Sibling taxa | ||
Synonyms | E. acris subsp. debilis, E. acris var. debilis, E. angulosus subsp. debilis, E. debilis, E. elatus var. bakeri, E. jucundus, E. scotteri, Trimorpha acris var. debilis | |
Name authority | Nuttall: Trans. Amer. Philos. Soc., n. s. 7: 311. (1841) | Nuttall: Trans. Amer. Philos. Soc., n. s. 7: 307. (1840) |
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