Foothills, montane. Openings, meadows. Spring, summer.
Lizard Head Trail, June 19, 2004.

Oenothera flava flowers are one-and-a half to two inches across and so bright that they always catch attention.  The long pink flower tube is usually overlooked.  Flowers open late in the day and wilt to a gnarled pink mass (see center and bottom of picture) early the next day.  Oenothera flava likes moist areas and it grows there with an abundance of dark green, wavy-edged leaves.

"Flava" is Latin for "yellow".  Marcus Jones collected the first specimen of this plant in 1894 in Utah and the plant was first named Oenothera triloba variety ecristata by Aven Nelson in 1895.  It was renamed Oenothera flava in 1927 by Albert Garrett.

Foothills, montane. Openings, meadows. Spring, summer.
Navajo Lake Trail, July 11, 2005.

Semi-desert. Washes, roadsides, sand. Summer, fall.
Hunter Canyon, Utah, September 26, 2005.

Oenothera longissima grabs and holds your attention with its large and brilliant yellow flowers, with its size -- commonly four-to-six feet tall, and certainly with its striking four-to six inch long hypanthium, the tube formed by the fusion of the bases of the stamens, petals, and sepals.  (In the photograph at left, the hypanthium is the long tube just below each flower.)  But at the same time it is easy to pass by Oenothera longissima because it does often grow with other thick vegetation and its leaves are quite Willow-like.  Look for it in sandy washes and riparian areas in the company of Cottonwood.

Per Axel Rydberg was the first to collect this plant for science in the Natural Bridges area of Utah in 1911 and he named it in 1913.  (More biographical information.)

Semi-desert. Washes, roadsides, sand. Summer, fall.
Hunter Canyon, Utah, September 26, 2005.

Semi-desert. Washes, roadsides, sand. Summer, fall.
Near Bluff, Utah, September 2, 2007.

Oenothera longissima is tall and slender with widely spaced stem leaves, but basal leaves are massed.