• Double O Arch

    Arches

    National Park Utah

Bridges Evening-primrose (Tall Yellow Evening-primrose)

Oenothera longissima

Oenothera longissima

Family: Onagraceae (Evening-primrose Family)

Perennial or biennial herbs; stems 7.9” to 5.9' (2 to 18 dm) tall or more

Leaves: alternate and basal; simple; can be toothed; 0.8” to 14” (2 to 35 cm) long, 0.12” to 1.8” (0.3 to 4.5 cm) wide

Flowers: 4 yellow petals; 4 sepals; 8 stamens; 4 lobed stigma; bisexual; usually radially symmetrical; fragrant; 1” to 2” (2.5 to 5 cm) long

Pollinators: other Oenothera species are pollinated by bees, moths and butterflies

Fruits: 4 chambered capsule

Blooms in Arches National Park: April, May, June, July, August, September, October

Habitat in Arches National Park: disturbed areas, riparian areas and hanging garden communities

Location seen: lower and upper Courthouse wash

Other: The genus name, “Oenothera”, means “wine-scented” and refers to the use of the roots in winemaking. The species name, “longissima”, refers to the long corolla tube or hypanthium.

The type specimen was collected in 1911 in Natural Bridges National Monument in southeast Utah which is where one of the common names comes from.

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