Erigeron caespitosus |
Erigeron trifidus |
|
---|---|---|
tuft daisy, tuft fleabane |
Alberta fleabane, three-lobed daisy |
|
Habit | Perennials, 5–25(–30) cm; taprooted, caudices relatively thick, usually branched. | Perennials, 3–8(–10) cm; taprooted, caudex branches rhizomelike, relatively thick to thin, woody. |
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. |
mostly erect, hispido-hirsute, sometimes woolly distally, 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. |
basal (persistent); blades spatulate to obovate-spatulate, 8–30 × 3–6 mm, margins usually 3-lobed, sometimes 2-lobed or entire (lobes 3–8 mm, lanceolate to narrowly ovate or oblong, apices usually acute), ultimately entire, coarsely ciliate, faces hirsute, minutely glandular. |
Involucres | 4–7 × 9–18 mm. |
8–12 × 10–15 mm. |
Ray florets | 30–100; corollas white to bluish, 5–15 mm, laminae coiling. |
20–40; corollas white to pinkish, 10–15 mm, laminae not coiling or reflexing. |
Disc corollas | 3–4.4 mm. |
3.5–4.5 mm. |
Phyllaries | in 3–4 series, densely hirsuto-canescent to hirtellous (hairs spreading), moderately minutely glandular. |
in 2–3 series (purplish or purple-tipped), hirsute to villoso-hirsute, 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. |
2–2.5 mm, 2-nerved, faces sparsely strigose; pappi: outer of setae, inner of 15–20 bristles (not twisted). |
2n | = 18, 36. |
= 45. |
Erigeron caespitosus |
Erigeron trifidus |
|
Phenology | Flowering Jun–Aug. | Flowering Jul–Aug. |
Habitat | Rocky or sandy, grassy hills, sagebrush-aspen, pinyon-juniper, to spruce and tundra northward | Dry talus and scree slopes in upper alpine zone |
Elevation | 1300–3000(–3600) m (4300–9800(–11800) ft) | ca. 2600–3400 m (ca. 8500–11200 ft) |
Distribution |
AK; AZ; CO; ID; MT; ND; NE; NM; SD; UT; WA; WY; AB; BC; MB; SK; YT
|
AB; 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 trifidus has been treated as a synonym of E. compositus; caudex branches of the latter usually are relatively thick and short, compared to those of E. trifidus, which are thinner and are not covered with persistent leaf bases. Leaves of E. trifidus are consistently 3-lobed. Erigeron trifidus was hypothesized (J. G. Packer 1983) to be of hybrid origin (based on its polyploid chromosome number and sterile pollen), with E. lanatus and E. compositus as the most likely parents (based on intermediate morphology and sympatry of the putative parents). (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Source | FNA vol. 20, p. 283. | FNA vol. 20, p. 301. |
Parent taxa | Asteraceae > tribe Astereae > Erigeron | Asteraceae > tribe Astereae > Erigeron |
Sibling taxa | ||
Synonyms | E. compositus var. trifidus | |
Name authority | Nuttall: Trans. Amer. Philos. Soc., n. s. 7: 307. (1840) | Hooker: Fl. Bor.-Amer. 2: 17, plate 120. (1834) |
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