Oenothera texensis |
Oenothera triangulata |
|
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Texas evening primrose |
prairie beeblossom |
|
Habit | Herbs perennial, caulescent, strigillose and also sparsely hirsute; from slender taproot. | Herbs annual, villous proximally, sparsely villous along veins and on margins, usually glabrate, sometimes strigillose distally; from taproot. |
Stems | several–many, ascending, unbranched or branched, 25–50 cm. |
ascending, usually well-branched from base and distally, rarely unbranched, 15–60 cm. |
Leaves | in a basal rosette and cauline, basal (1–)2.5–6.5 × 0.6–2.3 cm, blade narrowly elliptic to narrowly ovate or ovate, margins weakly serrulate to sinuate-pinnatifid; cauline 1–5.5 × 0.6–2 cm, blade narrowly elliptic to narrowly ovate, margins weakly serrulate. |
in a basal rosette and cauline, 1.5–8 × 0.2–0.6(–1.5) cm, blade very narrowly elliptic to oblanceolate or oblong-elliptic, margins entire or weakly sinuate-dentate. |
Inflorescences | erect. |
|
Flowers | 1–3 opening per day near sunrise; buds with free tips 0–1 mm; floral tube 15–26 mm; sepals 15–23 mm; petals rose purple, fading darker, 12–25(–30) mm; filaments 9–13 mm, anthers 3.5–6mm, pollen 85–100% fertile; style 26–36 mm, stigma exserted beyond anthers at anthesis. |
3(or 4)-merous, zygomorphic, opening at sunset; floral tube 4–5.5 mm; sepals 4.5–6 mm; petals white, fading pink, elliptic-obovate, 3.5–5 mm; filaments 2–3.5 mm, anthers 1.5–3 mm, pollen 35–65% fertile; style 9–10 mm, stigma surrounded by anthers. |
Capsules | clavate or narrowly obovoid, 9–15 × 3.5–6 mm, apex attenuate to a sterile beak, valve midrib prominent in distal part, proximal stipe 7–12(–28) mm, gradually taperingto base; sessile. |
narrowly obovoid, 3(or 4)-winged, furrowed between wings, 7–9 × 3–5 mm, narrowed at base; sessile. |
Seeds | narrowly obovoid, 0.8–1 × 0.2–0.4 mm. |
(1 or)2–5, yellowishto light brown, 1.5–3.5 × 1–1.5 mm. |
2n | = 14. |
= 14. |
Oenothera texensis |
Oenothera triangulata |
|
Phenology | Flowering May–Sep. | Flowering Apr–Jul. |
Habitat | Sandy and gravel bars of streambeds and along streams. | Open, sandy sites. |
Elevation | 900–2500 m. (3000–8200 ft.) | 200–600 m. (700–2000 ft.) |
Distribution |
TX; Mexico (Coahuila, Tamaulipas) |
OK; TX |
Discussion | In the flora area, Oenothera texensis is known only from Jeff Davis County. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Oenothera triangulata is a PTH species and forms a ring of 14 chromosomes in meiosis. The species is self-compatible and autogamous (P. H. Raven and D. P. Gregory 1972[1973]). It may have been derived from hybridization between O. patriciae and O. suffulta. The species has a relatively narrow distribution across south-central Oklahoma and north-central Texas (Oklahoma in Cleveland, Comanche, Cotton, Grady, Oklahoma, Rogers, Stephens, and Tulsa counties; Texas in Archer, Baylor, Callahan, Clay, Coleman, Crosby, Eastland, Erath, Jones, Montague, Taylor, Throckmorton, Tom Greene, Wichita, Wilbarger, and Young counties). (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Source | FNA vol. 10. | FNA vol. 10. |
Parent taxa | ||
Sibling taxa | ||
Synonyms | Gaura triangulata, G. hexandra var. triangulata, G. tripetala var. triangulata | |
Name authority | P. H. Raven & D. R. Parnell: Madroño 20: 247. (1970) | (Buckley) W. L. Wagner & Hoch: Syst. Bot. Monogr. 83: 214. (2007) |
Web links |