Oenothera mexicana

Herbs annual, moderately to sparsely strigillose and densely long-villous, sometimes also becoming glandular puberulent distally. Stems erect to ascending, usually unbranched, or with arcuate lateral branches arising from rosette, 15–40 (–60) cm. Leaves in a basal rosette and cauline, basal 6–10 × 1–2.5 cm, cauline 3–7.5 × 0.8–2 cm; blade usually grayish green, narrowly oblanceolate to narrowly oblanceolate, margins deeply lobed, lobes usually dentate; bracts distalmost erect, revolute. Flowers usually 1 opening per day near sunset; buds erect, with free tips erect or appressed, 0.5–2.5 mm; floral-tube 23–28 mm; sepals 5–12 mm; petals yellow, fading orange, broadly obovate or shallowly obcordate, 6–15 mm; filaments 4–12 mm, anthers 3–4 mm, pollen 85–100% fertile; style 27–40 mm, stigma surrounded by anthers at anthesis. Capsules cylindrical, sometimes slightly enlarged toward apex, 25–45 × 2.5–3 mm. Seeds ellipsoid to subglobose, 0.8–1.2 × 0.3–0.5 mm. 2n = 14.

Phenology: Flowering Apr–May.
Habitat: Open, sandy sites.
Elevation: 30–200 m.

Tex.

Discussion

Oenothera mexicana is known only from southeastern Texas (Atascosa, Aransas, Bexar, Brooks, Burleson, De Witt, Frio, Gonzales, Kenedy, Medina, Newton, Refugio, San Patricio, Waller, and Washington counties). It is self-compatible and autogamous, but not a PTH species.

Selected References

None.

Lower Taxa