Erigeron grandiflorus |
Erigeron trifidus |
|
---|---|---|
large-flower daisy, large-flower fleabane, onestem fleabane, Rocky Mountain alpine fleabane |
Alberta fleabane, three-lobed daisy |
|
Habit | Perennials, 2–25 cm; rhizomatous, fibrous-rooted, caudices or rhizomes crownlike or branches relatively short and thick. | Perennials, 3–8(–10) cm; taprooted, caudex branches rhizomelike, relatively thick to thin, woody. |
Stems | erect to decumbent-ascending, sparsely to moderately pilose to villoso-hirsute, often stipitate-glandular over all or part. |
mostly erect, hispido-hirsute, sometimes woolly distally, minutely glandular. |
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); 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 | 5–8(–10) × 8–20 mm. |
8–12 × 10–15 mm. |
Ray florets | 50–130; corollas blue to pink or purplish, rarely white, 7–11(–15) mm (mostly 1–2 mm wide), laminae coiling. |
20–40; corollas white to pinkish, 10–15 mm, laminae not coiling or reflexing. |
Disc corollas | 2.4–4(–5) mm. |
3.5–4.5 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 2–3 series (purplish or purple-tipped), hirsute to villoso-hirsute, 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 setae, inner of 15–20 bristles (not twisted). |
2n | = 18, 27. |
= 45. |
Erigeron grandiflorus |
Erigeron trifidus |
|
Phenology | Flowering Jul–Aug(–Sep). | Flowering Jul–Aug. |
Habitat | Rocky sites, meadows, alpine or near timberline | Dry talus and scree slopes in upper alpine zone |
Elevation | 2900–4200 m (9500–13800 ft) | ca. 2600–3400 m (ca. 8500–11200 ft) |
Distribution |
AZ; CO; ID; MT; NM; OR; UT; WY; AB; BC
|
AB; BC |
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 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. 324. | FNA vol. 20, p. 301. |
Parent taxa | ||
Sibling taxa | ||
Synonyms | E. simplex | E. compositus var. trifidus |
Name authority | Hooker: Fl. Bor.-Amer. 2: 18, plate 123. (1834) | Hooker: Fl. Bor.-Amer. 2: 17, plate 120. (1834) |
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