Erigeron caespitosus |
Erigeron nanus |
|
---|---|---|
tuft daisy, tuft fleabane |
dwarf fleabane |
|
Habit | Perennials, 5–25(–30) cm; taprooted, caudices relatively thick, usually branched. | Perennials, 2–10 cm; taprooted, caudices with relatively short and thick 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, hispido-hirsutulous to hirsute (hairs spreading, stiff, usually of unequal lengths, relatively thick-based), minutely 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. |
mostly basal (persistent) (petioles prominently ciliate, hairs thick-based, spreading); blades linear-oblanceolate, 20–40 × 1–2(–3) mm, margins entire, often coarsely spreading-ciliate, faces hispido-hirsute to hirsute or glabrous, abaxial sometimes glabrous, sometimes sparsely minutely glandular; cauline abruptly reduced, restricted to proximal 1/3 of stems. |
Involucres | 4–7 × 9–18 mm. |
5–8 × 7–13 mm. |
Ray florets | 30–100; corollas white to bluish, 5–15 mm, laminae coiling. |
15–35; corollas usually blue to purplish, rarely white, 5–10 mm, laminae coiling. |
Disc corollas | 3–4.4 mm. |
3.9–5.5 mm. |
Phyllaries | in 3–4 series, densely hirsuto-canescent to hirtellous (hairs spreading), moderately minutely glandular. |
in 2–3(–4) series, densely villous proximally, hirsute to hirsuto-villous, minutely 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. |
2.2–2.8 mm, 2-nerved, faces sparsely strigose to glabrate; pappi: outer of setae, bristles, or scales, inner of 15–23 bristles. |
2n | = 18, 36. |
|
Erigeron caespitosus |
Erigeron nanus |
|
Phenology | Flowering Jun–Aug. | Flowering May–Jun. |
Habitat | Rocky or sandy, grassy hills, sagebrush-aspen, pinyon-juniper, to spruce and tundra northward | Dry sites, ridges, rocky slopes, clay slopes, quartzite outcrops, sagebrush, pine-fir |
Elevation | 1300–3000(–3600) m (4300–9800(–11800) ft) | 1900–2700(–3200) m (6200–8900(–10500) ft) |
Distribution |
AK; AZ; CO; ID; MT; ND; NE; NM; SD; UT; WA; WY; AB; BC; MB; SK; YT
|
ID; NV; UT; WY |
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 nanus is unusually variable in leaf vestiture. The tendency (especially in Cassia County, Idaho) for sparsely strigose adaxial and glabrous abaxial leaf faces is similar to that of the E. radicatus group; longer disc corollas and the strong tendency for unequal-length stem hairs, plus spreading-ciliate petioles, place E. nanus closer to E. disparipilus and E. poliospermus. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Source | FNA vol. 20, p. 283. | FNA vol. 20, p. 285. |
Parent taxa | Asteraceae > tribe Astereae > Erigeron | Asteraceae > tribe Astereae > Erigeron |
Sibling taxa | ||
Name authority | Nuttall: Trans. Amer. Philos. Soc., n. s. 7: 307. (1840) | Nuttall: Trans. Amer. Philos. Soc., n. s. 7: 308. (1840) |
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