Erigeron quercifolius |
Erigeron denalii |
|
---|---|---|
oak-leaf fleabane |
Denali fleabane |
|
Habit | Perennials, 1–5 cm; taprooted, caudices diffuse with extensive systems of rhizomelike, relatively long and slender branches. | |
Stems | erect to basally ascending (green proximally), proximally villous to villoso-hirsute, distally loosely strigose to hirsute, eglandular. |
erect (simple, ± scapiform), villous, granular-glandular. |
Leaves | basal (persistent) and cauline; basal blades oblanceolate to obovate or spatulate, 15–110(–150) × 4–25(–30) mm, margins serrate or crenate to pinnately lobed, faces hirsute to villous, eglandular; cauline blades becoming oblong, gradually reduced distally (reduced to bracts or 0 proximal to arrays, clasping to subclasping). |
basal (persistent) and cauline; blades spatulate to oblanceolate-spatulate, 10–20 × 2–4(–5) mm, mid larger than basal and proximal, margins entire or shallowly (2–)3-lobed or -toothed apically (apices obtuse to nearly truncate), faces moderately villous, minutely glandular. |
Involucres | 2.5–4 × 4.5–10 mm. |
(4–)5–7 × 9–12 mm. |
Ray florets | 100–150; corollas usually blue, sometimes white to pink, 4–6 mm, laminae not coiling or reflexing. |
30–55; corollas white to lavender, 4–8 mm, laminae (filiform to narrowly straplike, 0.3–2 mm wide, often involute) erect, rarely spreading, not coiling or reflexing. |
Disc florets/ |
1.5–2.8 mm. |
3.8–4.8 mm. |
Phyllaries | in (2–)3–4 series (sometimes basally connate), strigose to hirsuto-villous, eglandular or sparsely minutely glandular. |
in 2(–3) series, densely lanate-villous (hairs to 3 mm, often with dark purple cross walls), glandular. |
Heads | (1–)4–16(–50) in corymbiform arrays (from branches distal to midstem). |
1. |
Cypselae | 0.6–0.9 mm, 2-nerved, faces sparsely strigose; pappi: outer of setae, inner of 10–15 bristles. |
3–3.8 mm, 2-nerved, faces strigillose to strigoso-hirsute; pappi: outer 0 (or inconspicuous), inner of 20–25 (usually ± purple-red tinged, sometimes whitish, variable within populations) bristles. |
Winter | annuals, biennials, or short-lived perennials, 10–60 cm; fibrous-rooted, caudices simple. |
|
2n | = 18. |
|
Erigeron quercifolius |
Erigeron denalii |
|
Phenology | Flowering (Feb–)Mar–Jun. | Flowering Jun–Aug. |
Habitat | Sandy sites, shell rock, roadsides, ditches, fields, areas of pine flatwoods | Open alpine and subalpine habitats, tundra slopes, openings in spruce-fir woods, gravelly and shaley scree, cut banks |
Elevation | 0–15 m (0–0 ft) | 900–2200 m (3000–7200 ft) |
Distribution |
FL; GA; NC; SC; VA; West Indies (Bahama Islands)
|
AK; NT; YT; BC |
Discussion | Erigeron quercifolius is primarily of the Atlantic coastal plain. Putative records from Alabama westward to Texas are based on specimens of E. philadelphicus or E. tenuis. Erigeron tenuis sometimes closely approaches E. quercifolius in overall appearance; it is more closely related to E. strigosus. Convergent plants of E. tenuis differ from E. quercifolius in their non-clasping cauline leaves, lanceolate (versus oblanceolate to obovate) phyllaries, and slightly longer cypselae (1–1.2 mm versus 0.6–0.9 mm). (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Erigeron denalii and E. purpuratus are similar and probably closely related; the two appear to be partially sympatric; differences in vestiture and leaf morphology are constant. The habitat of E. purpuratus, sandy or gravelly alluvium, also is remarkably constant and distinct from that of E. denalii. Apparently correlated with the habitat, plants of E. purpuratus almost always develop a relatively long and slender, woody taproot; taproots of E. denalii apparently are less well defined and often are not collected. Plants of the type collection of Erigeron mexiae have ray corollas with relatively broad laminae (1.5–2 mm wide); ray corolla width is variable in E. denalii, and E. mexiae is regarded here as an extreme variant within the species. In other characters, there appears to be no difference. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Source | FNA vol. 20, p. 320. | FNA vol. 20, p. 303. |
Parent taxa | Asteraceae > tribe Astereae > Erigeron | Asteraceae > tribe Astereae > Erigeron |
Sibling taxa | ||
Synonyms | E. mexiae, E. purpuratus var. dilatatus | |
Name authority | Lamarck: in J. Lamarck and J. Poiret, Tabl. Encycl. 3: 258. (1796) | A. Nelson: Amer. J. Bot. 32: 289. (1945) |
Web links |
|