Erigeron robustior |
Erigeron grandiflorus |
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robust daisy, white cushion fleabane, Willamette fleabane |
large-flower daisy, large-flower fleabane, onestem fleabane, Rocky Mountain alpine fleabane |
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Habit | Perennials, (15–)25–55 cm (not colonial); taprooted, taproots thin (2–3 mm wide), caudices simple or with relatively slender and short, erect branches. | Perennials, 2–25 cm; rhizomatous, fibrous-rooted, caudices or rhizomes crownlike or branches relatively short and thick. |
Stems | (often purplish) erect or decumbent, sparsely strigillose (basal cells inclined, hairs even-width), eglandular. |
erect to decumbent-ascending, sparsely to moderately pilose to villoso-hirsute, often stipitate-glandular over all or part. |
Leaves | basal (often withering by flowering) and cauline; basal blades (3-nerved) linear to narrowly oblanceolate, 90–170 × 3–7 mm; cauline gradually reduced distally, ending proximal to heads, margins entire, faces strigoso-hirsute, 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 | 6–8.5 × (12–)14–20 mm. |
5–8(–10) × 8–20 mm. |
Ray florets | 21–36; corollas 7–15(–19) mm, laminae white to pinkish, not coiling or reflexing. |
50–130; corollas blue to pink or purplish, rarely white, 7–11(–15) mm (mostly 1–2 mm wide), laminae coiling. |
Disc corollas | 3.5–4.5 mm. |
2.4–4(–5) mm. |
Phyllaries | in 2–3(–4) series (narrowly oblanceolate to lanceolate, acute-acuminate), sparsely to moderately hirsute to villous, eglandular. |
in 2–3 series (green or purplish), moderately to densely woolly-villous (hairs flattened, cross walls sometimes reddish), minutely glandular at least apically. |
Heads | 1–3. |
1. |
Cypselae | (1.8–)2–3.2 mm, 2-nerved, faces sparsely strigose; pappi: outer of setae, inner of 15–22 bristles. |
1.8–2.4 mm, 2-nerved, faces strigose; pappi: outer of setae, inner of (7–)10–18(–22) bristles. |
2n | = 18, 27. |
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Erigeron robustior |
Erigeron grandiflorus |
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Phenology | Flowering Jun–Jul. | Flowering Jul–Aug(–Sep). |
Habitat | Rocky or gravelly slopes, sometimes over serpentine, glades and meadows, seeps, sagebrush-scrub, proximal montane coniferous forest | Rocky sites, meadows, alpine or near timberline |
Elevation | (200–)700–1500 m ((700–)2300–4900 ft) | 2900–4200 m (9500–13800 ft) |
Distribution |
CA
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AZ; CO; ID; MT; NM; OR; UT; WY; AB; BC
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Discussion | 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.) |
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Source | FNA vol. 20, p. 279. | FNA vol. 20, p. 324. |
Parent taxa | Asteraceae > tribe Astereae > Erigeron | Asteraceae > tribe Astereae > Erigeron |
Sibling taxa | ||
Synonyms | E. decumbens subsp. robustior, E. decumbens var. robustior | E. simplex |
Name authority | (Cronquist) G. L. Nesom: Sida 21: 21. (2004) | Hooker: Fl. Bor.-Amer. 2: 18, plate 123. (1834) |
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