Common Evening Primrose
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Oenothera biennis
Introduced, naturalized species in Britain.
The leaves are lanceolate, 8–18 cm (3–7 in) long and 2–6 cm (3⁄4–2+1⁄4 in) wide,[6] produced in a tight rosette the first year, and spirally on a stem the second year.
However, plants with annual life cycles are documented, and have been selected for under experimental conditions in environments with low competition.
The blooms are yellow, 2.5–5 cm (1–2 in) diameter, with four bilobed petals.
The flower structure has a bright nectar guide pattern, invisible to the naked eye.
This pattern is apparent under ultraviolet light and visible to its pollinators, Moths, Butterflies, and Bees.
Flowers from June-September.