Oenothera elata (Tall/Hooker’s/Hairy/Western/Marsh Evening Primrose) is a tall biennial native to much of western and central North America, with one or more upright stems bearing a profusion of large bright yellow flowers, 3 in (7 cm) across. I was intrigued to see a bee burrowing deep into the flower’s throat, rather than gathering pollen from the prominent stamens and pistil.