Erigeron neomexicanus |
Erigeron porsildii |
|
---|---|---|
New Mexico fleabane |
Porsild's arctic fleabane |
|
Habit | Perennials, 20–70 cm; taprooted, caudices woody. | Perennials, (2–)10–20(–25) cm; rhizomatous, fibrous-rooted, rhizomes horizontal or erect, sometimes branched, relatively short, sometimes resembling taproots. |
Stems | erect, moderately to densely strigose (hairs appressed to ascending, 0.1–0.8(–2) mm, sometimes spreading at bases or throughout), eglandular or glands minute, non-capitate. |
erect, sparsely to moderately villous (hairs 0.5–1.6 mm), usually stipitate-glandular (hairs 0.05–0.4 mm). |
Leaves | basal (sometimes persistent) and cauline; blades oblanceolate, margins usually deeply pinnatifid (lobes in 2–5 pairs), sometimes dentate to entire, faces strigose, eglandular; basal 10–60 × 6–35 mm, cauline gradually reduced distally. |
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 | 3.5–5 × 7–12 mm. |
6–10 × 12–20 mm. |
Ray florets | 70–150; corollas white, drying white, (2–)6–15 mm, laminae reflexing. |
65–110; corollas white to lavender or blue, 13–17 mm (1.2–1.7 mm wide), laminae weakly coiling. |
Disc corollas | 2.5–3.3 mm (throats somewhat white-indurate, not inflated). |
3.8–4.5 mm. |
Phyllaries | in 3–4 series, strigose to hirsute (hairs arising mostly from midregion), usually minutely glandular, rarely eglandular. |
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–)5–15(–30) in loosely corymbiform arrays. |
1. |
Cypselae | 1–1.3 mm, 2(–4)–nerved, faces sparsely strigose; pappi: (outer 0) inner (readily falling) of (8–)10–12 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, 36. |
= 36. |
Erigeron neomexicanus |
Erigeron porsildii |
|
Phenology | Flowering (Jul–)Aug–Oct(–Dec). | Flowering (Jun–)Jul–Aug(–Sep). |
Habitat | Open, rocky sites, from grasslands into oak or pine woodlands, often with madrono, juniper, or fir | Cliffs and talus (often calcareous) slopes, shaley gravel, grassy ravines, dry tundra |
Elevation | (900–)1500–2700(–3000) m ((3000–)4900–8900(–9800) ft) | 600–2100 m (2000–6900 ft) |
Distribution |
AZ; NM; Mexico (Chihuahua, Sonora)
|
AK; NT; YT |
Discussion | Relatively large, pinnatifid leaves are typical of Erigeron neomexicanus; plants with nearly entire leaves can be identified by the strongly perennial habit, white, reflexing rays, and 10–12 readily falling pappus bristles. Erigeron neomexicanus and E. oreophilus were treated by A. Cronquist (1947) as varieties of one species, and their morphologic similarity and the closeness of their geographic ranges support that hypothesis. But relatively few collections are found that could be regarded as intermediates, and both forms sometimes grow in proximity, apparently without a range of intermediates. In some Arizona mountain ranges, apparently only one or the other taxon occurs. Still, the possibility exists that these are populational segregants of a single species (see further comments in G. L. Nesom 1989d). (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. 277. | FNA vol. 20, p. 324. |
Parent taxa | Asteraceae > tribe Astereae > Erigeron | Asteraceae > tribe Astereae > Erigeron |
Sibling taxa | ||
Synonyms | E. delphiniifolius var. euneomexicanus, E. delphiniifolius subsp. neomexicanus | E. grandiflorus subsp. arcticus |
Name authority | A. Gray: Proc. Amer. Acad. Arts 19: 2. (1883) | G. L. Nesom & D. F. Murray: Sida 21: 44. (2004) |
Web links |