Erigeron grandiflorus |
Erigeron porsildii |
|
---|---|---|
large-flower daisy, large-flower fleabane, onestem fleabane, Rocky Mountain alpine fleabane |
Porsild's arctic fleabane |
|
Habit | Perennials, 2–25 cm; rhizomatous, fibrous-rooted, caudices or rhizomes crownlike or branches relatively short and thick. | Perennials, (2–)10–20(–25) cm; rhizomatous, fibrous-rooted, rhizomes horizontal or erect, sometimes branched, relatively short, sometimes resembling taproots. |
Stems | erect to decumbent-ascending, sparsely to moderately pilose to villoso-hirsute, often stipitate-glandular over all or part. |
erect, sparsely to moderately villous (hairs 0.5–1.6 mm), usually stipitate-glandular (hairs 0.05–0.4 mm). |
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 (persistent) and cauline; basal blades oblong-oblanceolate to narrowly obovate, 30–120 × (3–)5–14 mm, margins entire (apices acute), faces densely hirsute to coarsely villous, sparsely stipitate-glandular to minutely glandular; cauline blades oblong-lanceolate to lanceolate, gradually reduced distally or nearly equal-sized (bases often subclasping). |
Involucres | 5–8(–10) × 8–20 mm. |
6–10 × 12–20 mm. |
Ray florets | 50–130; corollas blue to pink or purplish, rarely white, 7–11(–15) mm (mostly 1–2 mm wide), laminae coiling. |
65–110; corollas white to lavender or blue, 13–17 mm (1.2–1.7 mm wide), laminae weakly coiling. |
Disc corollas | 2.4–4(–5) mm. |
3.8–4.5 mm. |
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 ca. 2 series (purple at least at tips, narrowly lanceolate, equal, apically acuminate), densely hirsute, hirsuto-villous, or villous (hairs whitish, cross walls not colored), sparsely stipitate-glandular to minutely glandular. |
Heads | 1. |
1. |
Cypselae | 1.8–2.4 mm, 2-nerved, faces strigose; pappi: outer of setae, inner of (7–)10–18(–22) bristles. |
2–2.5 mm, 2-nerved, faces sparsely strigose; pappi: outer of relatively long setae or scales, inner of 14–20(–25) bristles. |
2n | = 18, 27. |
= 36. |
Erigeron grandiflorus |
Erigeron porsildii |
|
Phenology | Flowering Jul–Aug(–Sep). | Flowering (Jun–)Jul–Aug(–Sep). |
Habitat | Rocky sites, meadows, alpine or near timberline | Cliffs and talus (often calcareous) slopes, shaley gravel, grassy ravines, dry tundra |
Elevation | 2900–4200 m (9500–13800 ft) | 600–2100 m (2000–6900 ft) |
Distribution |
AZ; CO; ID; MT; NM; OR; UT; WY; AB; BC
|
AK; NT; YT |
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.) |
Erigeron hultenii S. A. Spongberg was noted to be “closely allied to the polymorphic arctic-alpine species E. grandiflorus W. J. Hooker” (S. A. Spongberg 1973, p. 116) and to have a “close morphologic resemblance to some plants of E. grandiflorus from Alaska” [E. porsildii in the present sense] (p. 119). Plants corresponding to E. hultenii have not been recollected, and that taxon does not fit with any other known Alaskan species. Contrasts with E. porsildii exclude it from that species. Erigeron hultenii is not recognized formally herein. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Source | FNA vol. 20, p. 324. | FNA vol. 20, p. 324. |
Parent taxa | Asteraceae > tribe Astereae > Erigeron | Asteraceae > tribe Astereae > Erigeron |
Sibling taxa | ||
Synonyms | E. simplex | E. grandiflorus subsp. arcticus |
Name authority | Hooker: Fl. Bor.-Amer. 2: 18, plate 123. (1834) | G. L. Nesom & D. F. Murray: Sida 21: 44. (2004) |
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