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diffuse-flower evening-primrose, long leaf suncup, long-leaf evening-primrose, northern sun-cup, stemless evening-primrose

Habit Herbs usually glabrate, rarely sparsely strigillose, especially on leaf blade veins and margins; taproot thick, deep, sometimes branched in age, producing new rosettes.
Leaves

2–22 × 0.7–4.2 cm;

petiole narrowly winged, 1–12 cm;

blade lanceolate to narrowly elliptic, base attenuate, margins usually subentire to sinuate, sometimes deeply and irregularly pinnatifid, apex acuminate.

Flowers

opening near sunrise;

floral tube 1.5–3 mm, with short, matted hairs inside near base;

sepals 4–15 mm, mostly glabrous, sometimes very minutely strigillose;

petals yellow, 5–16 mm, often apiculate; episepalous staminal filaments 1.8–6.5 mm, epipetalous ones 0.5–2.5 mm, anthers 0.9–2 mm;

sterile prolongation of ovary 15–80 mm, style 4–8.5(–11) mm, glabrous or sparsely pubescent near base, stigma usually surrounded by longer anthers at anthesis, rarely exserted beyond anthers.

Capsules

4-angled, oblong-ellipsoid, 11–28 × 5–8 mm, walls thick, scarcely distended by seeds, becoming blackened and persistent on plants for 1+ years after shedding seeds; rarely with pedicel to 10 mm.

Seeds

uniformly tan to light brown, ellipsoid-oblanceoloid, 1.3–1.9 × 0.6–1 mm, coarsely pitted.

2n

= 14.

Taraxia subacaulis

Phenology Flowering late Mar–Jul.
Habitat Meadows, seasonally moist open places, from foothills to mountains.
Elevation 400–2900 m. (1300–9500 ft.)
Distribution
from FNA
CA; CO; ID; MT; NV; OR; UT; WA; WY
[WildflowerSearch map]
[BONAP county map]
Discussion

Taraxia subacaulis occurs well inland from Pacific coastal areas. Its only occurrence in Colorado is in Moffat and Routt counties. P. H. Raven (1969) determined Taraxia subacaulis to be self-compatible and, usually, facultatively autogamous. The species is distinctive, but is sister to T. tanacetifolia in molecular analyses (R. A. Levin et al. 2004; W. L. Wagner et al. 2007).

(Discussion copyrighted by Flora of North America; reprinted with permission.)

Source FNA vol. 10.
Parent taxa Onagraceae > subfam. Onagroideae > tribe Onagreae > Taraxia
Sibling taxa
T. breviflora, T. ovata, T. tanacetifolia
Synonyms Jussiaea subacaulis, Camissonia subacaulis, Oenothera heterantha, O. heterantha var. taraxacifolia, O. subacaulis, O. subacaulis var. taraxacifolia, T. heterantha, T. taraxacifolia
Name authority (Pursh) Rydberg: Mem. New York Bot. Gard. 1: 281. (1900)
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