Erigeron neomexicanus |
Erigeron engelmannii |
|
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New Mexico fleabane |
Engelmann's fleabane |
|
Habit | Perennials, 20–70 cm; taprooted, caudices woody. | Perennials, 3–20(–30) cm; taprooted, caudex branches relatively short and thick. |
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, loosely to closely, sparsely to moderately strigose (hairs 0.1–0.9 mm), usually minutely glandular (glands barely evident), sometimes eglandular. |
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 (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 | 3.5–5 × 7–12 mm. |
3.5–5(–6) × 7–12 mm. |
Ray florets | 70–150; corollas white, drying white, (2–)6–15 mm, laminae reflexing. |
(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 | 2.5–3.3 mm (throats somewhat white-indurate, not inflated). |
(2.5–)2.7–4.2 mm (throats indurate and inflated, densely puberulent). |
Phyllaries | in 3–4 series, strigose to hirsute (hairs arising mostly from midregion), usually minutely glandular, rarely eglandular. |
in 2–3(–4) series, coarsely hirsuto-villous, sparsely to moderately minutely glandular. |
Heads | (1–)5–15(–30) in loosely corymbiform arrays. |
1(–3). |
Cypselae | 1–1.3 mm, 2(–4)–nerved, faces sparsely strigose; pappi: (outer 0) inner (readily falling) of (8–)10–12 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, 36. |
|
Erigeron neomexicanus |
Erigeron engelmannii |
|
Phenology | Flowering (Jul–)Aug–Oct(–Dec). | Flowering (Apr–)May–Jul. |
Habitat | Open, rocky sites, from grasslands into oak or pine woodlands, often with madrono, juniper, or fir | Dry, sandy or rocky sites, prairies, often with sagebrush, rabbitbrush, juniper, pinyon-juniper, salt desert shrub |
Elevation | (900–)1500–2700(–3000) m ((3000–)4900–8900(–9800) ft) | 1300–2500 m (4300–8200 ft) |
Distribution |
AZ; NM; Mexico (Chihuahua, Sonora)
|
CO; ID; UT; WY
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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.) |
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. 277. | FNA vol. 20, p. 290. |
Parent taxa | Asteraceae > tribe Astereae > Erigeron | Asteraceae > tribe Astereae > Erigeron |
Sibling taxa | ||
Synonyms | E. delphiniifolius var. euneomexicanus, E. delphiniifolius subsp. neomexicanus | |
Name authority | A. Gray: Proc. Amer. Acad. Arts 19: 2. (1883) | A. Nelson: Bull. Torrey Bot. Club 26: 247. (1899) |
Web links |