Erigeron filifolius |
Erigeron grandiflorus |
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Peck's threadleaf fleabane, thread-leaf daisy, thread-leaf fleabane |
large-flower daisy, large-flower fleabane, onestem fleabane, Rocky Mountain alpine fleabane |
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Habit | Perennials, 10–30(–50) cm; taprooted, caudices multicipital, often with relatively short and thin, stemlike, lignescent branches. | Perennials, 2–25 cm; rhizomatous, fibrous-rooted, caudices or rhizomes crownlike or branches relatively short and thick. |
Stems | erect, sparsely to densely strigose (hairs loosely appressed to ascending, fine), densely white-strigose at least proximally, eglandular. |
erect to decumbent-ascending, sparsely to moderately pilose to villoso-hirsute, often stipitate-glandular over all or part. |
Leaves | basal (usually persistent, not clustered as rosettes) and cauline; basal blades linear to filiform, 10–80 × 0.5–2.5(–3.5) mm; cauline gradually or little reduced distally, margins entire, faces sparsely to moderately strigose, eglandular. |
basal (persistent) and cauline (petioles equaling or shorter than blades); blades oblanceolate to obovate or spatulate, 10–60(–90) × 3–8(–14) mm, cauline abruptly or gradually reduced distally, margins entire (apices rounded), faces sparsely hirsutulous or villous to sparsely strigose or glabrate, sometimes sparsely glandular. |
Involucres | 4–7 × 5–-18 mm. |
5–8(–10) × 8–20 mm. |
Ray florets | (15–)20–125; corollas usually blue, sometimes white, pink, or pale lavender, 3–13 mm, laminae coiling. |
50–130; corollas blue to pink or purplish, rarely white, 7–11(–15) mm (mostly 1–2 mm wide), laminae coiling. |
Disc corollas | 2.5–5.5 mm. |
2.4–4(–5) mm. |
Phyllaries | in (2–)3–4 series, loosely strigose to hirsute or nearly villous, densely to sparsely minutely glandular. |
in 2–3 series (green or purplish), moderately to densely woolly-villous (hairs flattened, cross walls sometimes reddish), minutely glandular at least apically. |
Heads | 1–5(–10+) from distal branches, tending to be in corymbiform arrays. |
1. |
Cypselae | 1.4–1.8(–2) mm, 2-nerved, faces sparsely strigose to glabrate; pappi: outer of setae, inner of 20–30 bristles. |
1.8–2.4 mm, 2-nerved, faces strigose; pappi: outer of setae, inner of (7–)10–18(–22) bristles. |
2n | = 18. |
= 18, 27. |
Erigeron filifolius |
Erigeron grandiflorus |
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Phenology | Flowering May–Aug. | Flowering Jul–Aug(–Sep). |
Habitat | Dry, rocky or sandy soil, lava beds, bitterbrush, sagebrush, juniper, ponderosa pine | Rocky sites, meadows, alpine or near timberline |
Elevation | 400–2400 m (1300–7900 ft) | 2900–4200 m (9500–13800 ft) |
Distribution |
CA; ID; MT; NV; OR; UT; WA; BC
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AZ; CO; ID; MT; NM; OR; UT; WY; AB; BC
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Discussion | The densely white-strigose stem bases, linear-filiform leaves relatively unreduced distally, and relatively few heads with coiling, usually blue rays are distinctive for Erigeron filifolius. Proximal leaves are not clustered as a basal rosette; they are inserted on closely spaced nodes that are slightly more separated distally. Plants identified as var. robustior (with more ray florets, fewer heads, and thicker stems, centered in Oregon and Washington) intergrade with the typical form and apparently are separated arbitrarily. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
S. A. Spongberg (1971) recognized only the triploid populations as Erigeron grandiflorus and assigned the diploid ones to E. simplex. He hypothesized that the triploids incorporate genomic elements from an ancestor other than E. simplex. Based on his comments and annotations, however, triploids in southern Canada and the western United States apparently differ from the much more widespread diploids only quantitatively, having involucres and florets at the higher end of size ranges. Morphologic distinctions between the ploidal races do not provide a basis for consistent distinction. Spongberg (p. 200) also noted that “because of the intergrading of morphologic features of plants of Erigeron grandiflorus...the single most important criterion indicative of this taxon is highly irregular [in shape] and greatly abortive pollen.” These pollen features result from meiotic anomalies associated with the triploid condition. Specimen citations by A. Cronquist (1947) for Erigeron grandiflorus were mostly from collections of the species treated here as E. porsildii. He also cited two collections from southwestern Alberta; those and the type collection of E. grandiflorus (from the same region) are disjunct by more than 1500 kilometers from the more northern range of E. porsildii and instead lie at the northern extremity of the range of what previously has generally been identified as E. simplex. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Source | FNA vol. 20, p. 298. | FNA vol. 20, p. 324. |
Parent taxa | Asteraceae > tribe Astereae > Erigeron | Asteraceae > tribe Astereae > Erigeron |
Sibling taxa | ||
Synonyms | Diplopappus filifolius, E. filifolius var. robustior | E. simplex |
Name authority | (Hooker) Nuttall: Trans. Amer. Philos. Soc., n. s. 7: 308. (1840) | Hooker: Fl. Bor.-Amer. 2: 18, plate 123. (1834) |
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