Erigeron neomexicanus |
Erigeron radicatus |
|
---|---|---|
New Mexico fleabane |
Hooker's fleabane, Huber's fleabane, tap-root fleabane |
|
Habit | Perennials, 20–70 cm; taprooted, caudices woody. | Perennials, (1–)2–6(–12) cm; taprooted, caudices branches relatively short, 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, strigose to sparsely or densely short-villous (hairs loosely appressed to ascending or spreading), 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. |
mostly basal (persistent) (eciliate or weakly ciliate proximally); blades 1-nerved linear to narrowly oblanceolate or subspatulate, (5–)10–50(–60) × 0.8–2.5 mm (bases gradually narrowing), margins entire (apices obtuse to rounded), abaxial faces glabrate or glabrous, shiny, adaxial sparsely, loosely strigose, eglandular; cauline mostly on proximal 1/2–1/3 of stems (absent in some high elevation forms), abruptly or gradually reduced distally. |
Involucres | 3.5–5 × 7–12 mm. |
(3–)4–6(–8) × (5–)8–12(–15) mm. |
Ray florets | 70–150; corollas white, drying white, (2–)6–15 mm, laminae reflexing. |
(12–)20–44(–85); corollas white, less commonly purplish, 4–7(–8) mm, laminae coiling. |
Disc corollas | 2.5–3.3 mm (throats somewhat white-indurate, not inflated). |
(2–)2.5–3.5(–4) mm. |
Phyllaries | in 3–4 series, strigose to hirsute (hairs arising mostly from midregion), usually minutely glandular, rarely eglandular. |
in 2–3(–4) series (subequal), villosulous to villoso-hirsutulous (hairs usually with purplish cross walls at least in basal cells), minutely glandular apically or eglandular. |
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. |
2.1–2.5 mm, 2-nerved, faces sparsely strigose; pappi: outer of scales, inner of (6–)7–11 (readily falling) bristles. |
2n | = 18, 36. |
|
Erigeron neomexicanus |
Erigeron radicatus |
|
Phenology | Flowering (Jul–)Aug–Oct(–Dec). | Flowering May–Aug. |
Habitat | Open, rocky sites, from grasslands into oak or pine woodlands, often with madrono, juniper, or fir | Rocky slopes, ridges, and summits, ledges and crevices, outcrops and talus, usually limestone, alpine tundra |
Elevation | (900–)1500–2700(–3000) m ((3000–)4900–8900(–9800) ft) | (1400–)1600–2800(–3400) m ((4600–)5200–9200(–11200) ft) |
Distribution |
AZ; NM; Mexico (Chihuahua, Sonora)
|
CO; ID; MT; ND; NE; SD; UT; WY; AB; SK
|
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.) |
Collections of Erigeron radicatus often have been identified as E. ochroleucus var. scribneri; E. radicatus is distinctive in its branched caudex, villous cauline vestiture, more reduced leaf vestiture, involucral vestiture of hairs with purple cross walls, shorter disc corollas, and relatively few, readily falling pappus bristles. Erigeron radicatus often is essentially scapiform at relatively high elevation (2700–3400 m) in Idaho, Montana, Utah, and Wyoming; more eastern populations in the Great Plains, at lower elevations (1400–2600 m), have leafier stems but are hardly different in other features. Plants of some populations in Albany and Carbon counties, Wyoming, produce atypically shorter rays. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Source | FNA vol. 20, p. 277. | FNA vol. 20, p. 294. |
Parent taxa | Asteraceae > tribe Astereae > Erigeron | Asteraceae > tribe Astereae > Erigeron |
Sibling taxa | ||
Synonyms | E. delphiniifolius var. euneomexicanus, E. delphiniifolius subsp. neomexicanus | E. huberi, E. macounii |
Name authority | A. Gray: Proc. Amer. Acad. Arts 19: 2. (1883) | Hooker: Fl. Bor.-Amer. 2: 17, plate 122. (1834) |
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