Erigeron subtrinervis |
Erigeron speciosus |
|
---|---|---|
three-vein fleabane, threenerve fleabane |
aspen fleabane, showy daisy, showy fleabane, splendid fleabane |
|
Habit | Perennials, 15–90 cm; rhizomatous to subrhizomatous, fibrous-rooted, caudices usually branched, woody, thick. | Perennials, 30–80(–100) cm; rhizomatous, fibrous-rooted, caudices relatively thick. |
Stems | erect, moderately to densely hirsute (hairs 0.5–0.8 mm), eglandular. |
erect, glabrous or sparsely hirsuto-pilose (hairs 0.5–1 mm), often minutely glandular distally. |
Leaves | basal (usually withering by flowering) and cauline; basal blades oblanceolate-spatulate, 30–80 × 6–20(–27) mm, margins entire, faces evenly hirsute to strigoso-hirsute, usually eglandular; cauline blades lanceolate to oblong, oblong-ovate, or broadly ovate, nearly even-sized distally or sometimes mid largest (continuing to immediately proximal to heads, bases clasping to subclasping). |
basal (usually withering by flowering) and cauline; basal blades oblanceolate-spatulate, 30–80(–150) × 4–18(–28) mm, margins entire, often ciliate (main veins sometimes also), faces glabrous, eglandular or distal sparsely minutely glandular; cauline blades ovate to ovate-lanceolate, oblong-lanceolate, or lanceolate, nearly even-sized distally or sometimes mid largest (continuing to immediately below heads, bases usually clasping to subclasping). |
Involucres | 6–9 × 13–20 mm. |
6–9 × 11–22 mm. |
Ray florets | 100–150; corollas blue to lavender, 7–18 mm (ca. 1 mm wide), laminae coiling at tips. |
75–150; corollas blue to lavender, rarely whitish, 8–16 mm (mostly 1 mm wide), laminae slightly coiling at least at tips. |
Disc corollas | 4–5 mm. |
4–5 mm. |
Phyllaries | in 2–3(–4) series, moderately to densely hirsute, minutely glandular. |
in 2–3(–4) series, usually glabrous, sometimes sparsely hirsuto-pilose, minutely glandular. |
Heads | 1–6(–21) in corymbiform arrays. |
(2–)4–20 in corymbiform arrays. |
Cypselae | 1.6–2 mm, 2(–4)-nerved, faces sparsely strigose; pappi: outer of setae, inner of 20–30 bristles. |
1.5–1.8 mm, 2(–4)-nerved, faces sparsely strigose; pappi: outer of setae, inner of 20–30 bristles. |
Erigeron subtrinervis |
Erigeron speciosus |
|
Phenology | Flowering (Jun–)Jul–Sep. | Flowering Jul–Oct. |
Habitat | Opening and margins, roadsides, often shaded, ponderosa pine, pine-fir, mixed conifer, aspen | Dry or moist, gravelly or loamy soil, prairies, yellow pine, pine-fir, spruce-fir, aspen-spruce |
Elevation | 1800–3000(–3500) m (5900–9800(–11500) ft) | (600–)900–3400 m ((2000–)3000–11200 ft) |
Distribution |
CO; ID; MT; ND; NE; NM; SD; UT; WY
|
AZ; CO; ID; MT; NM; NV; OR; SD; UT; WA; WY; AB; BC; Mexico (Baja California)
|
Discussion | Erigeron subtrinervis is variable in vestiture, perhaps reflecting gene exchange with E. speciosus. Erigeron speciosus var. mollis (A. Gray) S. L. Welsh may be a recurrent hybrid; it is identified here within E. subtrinervis. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
The population in Baja California is disjunct from the closest range in Arizona and northern Nevada. Plants glabrous and glandular on the phyllaries, stems, and leaves have been recognized as var. macranthus; they intergrade with hairier forms and do not show a coherent geographic pattern. Plants commonly identified as Erigeron subtrinervis var. conspicuus usually have stems sparsely hirsuto-pilose with hairs 1–1.5 mm, and the leaves commonly are ciliate on the margins and veins. As implied in the nomenclatural combination by Breitung, those plants are more similar to E. speciosus than to E. subtrinervis, and they apparently show part of the greater variability of E. speciosus in the northwestern part of its range (Alberta, British Columbia, Idaho, Montana, Oregon, Washington, and Wyoming), where more typical plants also occur. Erigeron speciosus and E. subtrinervis are sympatric over large parts of their ranges and appear to be at least partially reproductively isolated entities, although intermediates are frequently encountered. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Source | FNA vol. 20, p. 330. | FNA vol. 20, p. 330. |
Parent taxa | Asteraceae > tribe Astereae > Erigeron | Asteraceae > tribe Astereae > Erigeron |
Sibling taxa | ||
Synonyms | E. glabellus var. mollis, E. speciosus var. mollis | Stenactis speciosa, E. conspicuus, E. macranthus, E. speciosus var. conspicuus, E. speciosus var. macranthus, E. subtrinervis subsp. conspicuus, E. subtrinervis var. conspicuus |
Name authority | Rydberg ex Porter & Britton: Mem. Torrey Bot. Club 5: 328. (1894) | (Lindley) de Candolle: in A. P. de Candolle and A. L. P. P. de Candolle, Prodr. 5: 284. (1836) |
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