Erigeron grandiflorus |
Erigeron engelmannii |
|
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large-flower daisy, large-flower fleabane, onestem fleabane, Rocky Mountain alpine fleabane |
Engelmann's fleabane |
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Habit | Perennials, 2–25 cm; rhizomatous, fibrous-rooted, caudices or rhizomes crownlike or branches relatively short and thick. | Perennials, 3–20(–30) cm; taprooted, caudex branches relatively short and thick. |
Stems | erect to decumbent-ascending, sparsely to moderately pilose to villoso-hirsute, often stipitate-glandular over all or part. |
erect, loosely to closely, sparsely to moderately strigose (hairs 0.1–0.9 mm), usually minutely glandular (glands barely evident), sometimes eglandular. |
Leaves | 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. |
basal (usually persistent) and cauline (petioles prominently ciliate at least on proximal portions, hairs spreading, thick-based); basal blades linear-oblanceolate, 20–100 × 1–4 mm, margins entire, faces strigose, eglandular; cauline usually restricted to proximal 1/2 of stems, slightly reduced distally. |
Involucres | 5–8(–10) × 8–20 mm. |
3.5–5(–6) × 7–12 mm. |
Ray florets | 50–130; corollas blue to pink or purplish, rarely white, 7–11(–15) mm (mostly 1–2 mm wide), laminae coiling. |
(35–)45–100; corollas white, sometimes pink or bluish, 5–10 mm, laminae (0.8–1.1 mm wide) primarily reflexing, sometimes also weakly coiling at the tips. |
Disc corollas | 2.4–4(–5) mm. |
(2.5–)2.7–4.2 mm (throats indurate and inflated, densely puberulent). |
Phyllaries | in 2–3 series (green or purplish), moderately to densely woolly-villous (hairs flattened, cross walls sometimes reddish), minutely glandular at least apically. |
in 2–3(–4) series, coarsely hirsuto-villous, sparsely to moderately minutely glandular. |
Heads | 1. |
1(–3). |
Cypselae | 1.8–2.4 mm, 2-nerved, faces strigose; pappi: outer of setae, inner of (7–)10–18(–22) bristles. |
1.4–1.8 mm (oblong), 2-nerved, faces sparsely strigose; pappi: outer usually of narrow scales, sometimes 0 or of setae, inner of 12–20 bristles. |
2n | = 18, 27. |
|
Erigeron grandiflorus |
Erigeron engelmannii |
|
Phenology | Flowering Jul–Aug(–Sep). | Flowering (Apr–)May–Jul. |
Habitat | Rocky sites, meadows, alpine or near timberline | Dry, sandy or rocky sites, prairies, often with sagebrush, rabbitbrush, juniper, pinyon-juniper, salt desert shrub |
Elevation | 2900–4200 m (9500–13800 ft) | 1300–2500 m (4300–8200 ft) |
Distribution |
AZ; CO; ID; MT; NM; OR; UT; WY; AB; BC
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CO; ID; UT; WY
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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.) |
Plants from Chaffee and Fremont counties, Colorado, have strigose leaves and the compact habit of Erigeron engelmannii but sparsely spreading-hirsute stems; they may be intermediate between E. engelmannii and E. concinnus. Unusual variation in the pappi of E. engelmannii also suggests that the species needs study and better definition. A. Cronquist observed that “Erigeron engelmannii intergrades completely with E. pumilus, yet has two geographic subspecies of its own, and shows no distributional similarity to the [taxa] of E. pumilus,” and that E. engelmannii is “smaller and more delicate, with shorter finer hairs, and [has] smaller heads with usually fewer ligules.” (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Source | FNA vol. 20, p. 324. | FNA vol. 20, p. 290. |
Parent taxa | Asteraceae > tribe Astereae > Erigeron | Asteraceae > tribe Astereae > Erigeron |
Sibling taxa | ||
Synonyms | E. simplex | |
Name authority | Hooker: Fl. Bor.-Amer. 2: 18, plate 123. (1834) | A. Nelson: Bull. Torrey Bot. Club 26: 247. (1899) |
Web links |