Oenothera triangulata |
Oenothera primiveris |
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prairie beeblossom |
desert evening primrose, yellow desert evening primrose |
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Habit | Herbs annual, villous proximally, sparsely villous along veins and on margins, usually glabrate, sometimes strigillose distally; from taproot. | Herbs winter-annual, caulescent to short-caulescent, long-hirsute, hairs often with reddish purple pustulate bases, especially proximally, also moderately strigillose, and glandular puberulent distally, often on leaves; from a weakly fleshy taproot. |
Stems | ascending, usually well-branched from base and distally, rarely unbranched, 15–60 cm. |
(when present) unbranched and erect or, sometimes, few branches from near base, in robust plants stems and caudex hollow and greatly enlarged, especially toward base, densely leafy, 5–35 cm. |
Leaves | 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. |
in a basal rosette, sometimes also cauline, (1.4–)6–15(–28) × (0.2–)1–3.5(–5.6) cm; petiole (0.9–)3.5–8(–14) cm; blade oblanceolate to linear-oblanceolate, pinnatifid or 2-pinnatifid to shallowly pinnately lobed, margins sinuate-dentate or subentire, apex obtuse. |
Flowers | 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. |
usually 1–4, rarely more, opening per day, 1–2 hours before sunset; sepals (7–)12–25(–30) mm; petals yellow, fading reddish orange to purple, obcordate to obovate, (6–)13–35(–40) mm; filaments 6–16 mm, anthers 3–10 mm; style (32–)40–90(–100) mm, stigma exserted beyond anthers or surrounded by them. |
Capsules | narrowly obovoid, 3(or 4)-winged, furrowed between wings, 7–9 × 3–5 mm, narrowed at base; sessile. |
woody in age, sigmoid or curved to nearly straight, lanceoloid to ovoid, 4-angled, 10–45(–60) × 4–8 mm, beak 4–15 mm, dehiscent 1/4–2/3 their length; sessile. |
Seeds | (1 or)2–5, yellowishto light brown, 1.5–3.5 × 1–1.5 mm. |
usually numerous, in 2 rows per locule, obovoid to oblanceoloid, 3–3.5 × 1–1.4 mm, surface thickened above raphe and at distal end into U-shaped structure. |
2n | = 14. |
= 14. |
Oenothera triangulata |
Oenothera primiveris |
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Phenology | Flowering Apr–Jul. | Flowering Feb–May(–Jun). |
Habitat | Open, sandy sites. | Sandy soil on flats, low hills and margins of sand dunes, along arroyos, roadsides, in desert scrub, grasslands and oak-grasslands. |
Elevation | 200–600 m. (700–2000 ft.) | 30–1600 m. (100–5200 ft.) |
Distribution |
OK; TX |
AZ; CA; NM; NV; TX; UT; Mexico (Baja California, Chihuahua, Sonora)
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Discussion | 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.) |
Oenothera primiveris has a complex variation pattern (W. L. Wagner 2005). In the western part of the range from southeastern California across southern Nevada to southern Utah counties of Emery, Kane, and Washington, and northwestern Mohave County, Arizona, plants generally have a gray appearance, with dense pubescence and larger flowers with widespread self-compatibility, but with scattered populations retaining self-incompatibility. Populations from southof the Mogollon Plateau to southern New Mexico, western Texas, Chihuahua, Sonora, and Baja California, Mexico, are greener in appearance with smaller to much smaller flowers, and are all self-compatible with occasional outcrossing or complete autogamy. The transitions between these two extremes are so extensive and more or less gradual that it is not possible to subdivide into two subspecies as has been done previously (Wagner). (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 | Lavauxia lobata, L. primiveris, O. bufonis, O. cespitosa var. primiveris, O. johnsonii, O. primiveris subsp. bufonis, O. primiveris var. bufonis, O. primiveris subsp. caulescens, O. primiveris var. caulescens, Pachylophus johnsonii |
Name authority | (Buckley) W. L. Wagner & Hoch: Syst. Bot. Monogr. 83: 214. (2007) | A. Gray: Smithsonian Contr. Knowl. 5(6): 58. (1853) |
Web links |