Agoseris ×elata

(Nuttall) Greene

Pittonia 2: 177. 1891.

Common names: Willamette agoseris
Basionym: Stylopappus elatus Nuttall Trans. Amer. Philos. Soc., n. s. 7: 433. 1841
Synonyms: Agoseris grandiflora var. laciniata (Nuttall) Jepson Agoseris laciniata (Nuttall) Greene Agoseris tenuifolia Rydberg Stylopappus laciniatus Nuttall Stylopappus laciniatus var. longifolius Nuttall Troximon grandiflorum var. laciniatum (Nuttall) A. Gray Troximon grandiflorum var. tenuifolium A. Gray Troximon nuttallii
Treatment appears in FNA Volume 19. Treatment on page 334. Mentioned on page 324, 325, 330.

Stems 0. Leaves erect to ascending; blades usually oblanceolate, sometimes lanceolate or obovate, 15–25 cm, margins usually toothed to lobed or pinnatifid, rarely entire, lobes 2–4 pairs, lanceolate to triangular, antrorse to spreading, lobules mostly 0, faces glabrous and glaucous or sparsely villous. Peduncles ± elongating after flowering, 15–65(–90) cm in fruit, glabrate, or apically pubescent or villous, ± stipitate-glandular. Involucres obconic to campanulate, 2–4 cm in fruit. Phyllaries in 2–4 series, medially rosy purple, sometimes purple-black apically, rarely all green or purple-black spotted, faces pubescent to villous, ± stipitate-glandular; outer mostly spreading, adaxially ± villous and eglandular; inner erect, elongating after flowering. Receptacles epaleate. Florets (25–)50–150; corollas orange or yellow, tubes 8–10 mm, ligules 6–8(–12) × 1–3 mm; anthers 2–3(–5) mm. Cypselae (11–)14–20 mm, bodies ± fusiform, (6–)8–10 mm, beaks 5–10 mm, mostly equaling bodies; ribs broadly ridged, straight; pappus bristles in 2–3 series, 10–14 mm.

Phenology: Flowering Jun–Sep.
Habitat: Lowland prairies
Elevation: 10–100 m



Oreg., Wash., and montane meadows or open pine forests, 1400–2800 m, Calif., Oreg., Wash.


Agoseris ×elata has been and continues to be an enigmatic taxon. Perhaps no other name in the genus has been so misunderstood and misapplied. Many herbarium specimens labeled A. ×elata are in fact misidentified. Specimens of A. ×elata are not abundant in herbaria; the number of actual collections is relatively small compared to those for other Agoseris. Specimens that belong to A. ×elata represent a complex assemblage that has relatively few defining features and appears to be of hybrid origin. Most specimens appear to be intermediate between A. grandiflora and A. aurantiaca; most also appear to have characteristics of A. monticola or A. glauca var. dasycephala. The exact parentage remains unclear.

Agoseris ×elata occurs in two geographically separated populations, which cannot be consistently distinguished morphologically: one mainly in scattered lowland prairie locations in the Puget Sound and Willamette Valley areas (the type collection came from this popula tion; no new collections have been taken from this region in over 65 years; it is likely extirpated) and another at high elevations in California, primarily in the Lake Tahoe region and southward in the Sierra Nevada.

Selected References


Lower Taxa

... more about "Agoseris ×elata"
Gary I. Baird +
(Nuttall) Greene +
Stylopappus elatus +
Willamette agoseris +
Oreg. +, Wash. +, and montane meadows or open pine forests +, 1400–2800 m +  and Calif. +
10–100 m +
Lowland prairies +
Flowering Jun–Sep. +
Agoseris grandiflora var. laciniata +, Agoseris laciniata +, Agoseris tenuifolia +, Stylopappus laciniatus +, Stylopappus laciniatus var. longifolius +, Troximon grandiflorum var. laciniatum +, Troximon grandiflorum var. tenuifolium +  and Troximon nuttallii +
Agoseris ×elata +
Agoseris +
species +