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Hill sun cup, slender flower evening primrose

Palmer's evening primrose, Palmer's sun cup

Habit Herbs densely pilose. Herbs sparsely to moderately strigose and sometimes also sparsely pilose.
Stems

rarely with ascending lateral branches to 2.5 cm.

rarely present, swollen, ascending to 2 cm.

Leaves

blade linear to very narrowly lanceolate, 1–9.8 ×0.1–0.9 cm, dilated at base, margins entire or very sparsely serrulate.

blade narrowly oblanceolate, 1.5–5.5 × 0.2–0.7 cm, dilated at base, margins sparsely and evenly serrulate.

Flowers

opening near sunrise;

floral tube 1.6–3.2 mm;

sepals 4.5–8 mm;

petals 5–18 mm; episepalous filaments 1.8–3.2 mm, epipetalous filaments 0.8–1.6 mm;

sterile projection of ovary 6–45 mm;

style 3–5.5 mm, short-hairy near base;

stigma 1–1.6 mm diam., surrounded by anthers of longer stamens at anthesis.

opening near sunrise;

floral tube 0.8–1.3 mm;

sepals 1.6–2.8 mm;

petals 2–5 mm; episepalous filaments 0.8–1 mm, epipetalous filaments 0.2 mm;

sterile projection of ovary 5.5–12 mm;

style 1–2.2 mm, glabrous;

stigma 0.3–0.6 mm diam., surrounded by anthers of long and short stamens.

Capsules

irregularly obovoid, sharply 4-angled, thick-walled, somewhat woody, with pointed wing near center-top of each valve, 4–8 × 2.6–4.8 mm, tardily dehiscent in distal 1/3.

irregularly obovoid, thick-walled, somewhat woody, sharply 4-angled, with pointed wing near center-top of each valve, 5–7 × 4.5–7 mm, tardily dehiscent in distal 1/2 only.

Seeds

tan with dark splotches, obovoid, 1.2–2 mm.

brown, narrowly obovoid, 1.2–2 mm.

2n

= 14.

= 14.

Tetrapteron graciliflorum

Tetrapteron palmeri

Phenology Flowering Mar–May. Flowering Mar–May.
Habitat Colonial on open or brushy slopes, on clay soil, grasslands, Yucca or juniper and oak shrublands. Desert habitats, on clay or sandy soil, creosote to sagebrush-juniper woodlands.
Elevation 0–800 m. (0–2600 ft.) 600–1400 m. (2000–4600 ft.)
Distribution
from FNA
CA; OR; Mexico (Baja California)
[WildflowerSearch map]
[BONAP county map]
from FNA
AZ; CA; NV; OR
[WildflowerSearch map]
[BONAP county map]
Discussion

Tetrapteron graciliflorum is rare in Oregon, known only from a few collections in Jackson and Josephine counties. In Baja California, Mexico, it is known only from Rancho Aguajito.

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

Tetrapteron palmeri has a disjunct distribution, occurring in four distinct areas: Arizona, represented only by the type specimens collected in the Colorado River valley in 1876; near Harper and Vale, Malheur County, Oregon; north of Winnemucca, Humboldt County, and Empire City, Ormsby County, Nevada; in California it is fairly common from southern Inyo County to the southwestern border of the Mojave Desert, west to the vicinity of Tejon Pass and southeastern San Luis Obispo County in the inner South Coast Ranges, and also east of Jacumba on the road to Mountain Springs in San Diego County.

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

Source FNA vol. 10. FNA vol. 10.
Parent taxa Onagraceae > subfam. Onagroideae > tribe Onagreae > Tetrapteron Onagraceae > subfam. Onagroideae > tribe Onagreae > Tetrapteron
Sibling taxa
T. palmeri
T. graciliflorum
Synonyms Oenothera graciliflora, Camissonia graciliflora, Taraxia graciliflora Oenothera palmeri, Camissonia palmeri, Taraxia palmeri
Name authority (Hooker & Arnott) W. L. Wagner & Hoch: Syst. Bot. Monogr. 83: 214. (2007) (S. Watson) W. L. Wagner & Hoch: Syst. Bot. Monogr. 83: 214. (2007)
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