Vascular Plants Image Gallery

Lewis River Evening Primrose
Oenothera cespitosa Nutt. 

An annual with branching stems up to 10 inches tall. The strap-shaped leaves are alternate and 4 to 10 inches long, 1/2 to 1 inch broad, the petioles slender, usually subequal to the runcinate or pinnatifid to remotely toothed or nearly entire blades.  Foliage is sparsely hairy to glandular. Petals white, aging to pinkish, 1 to 2 inches long.  Anthers 1/3 to inch long.  Stigma lobes to 1/3 inch long.  Capsule sessile, usually curved, tuberculate on the angles, to inch long.  Flowers late April through mid-June.  Flowers of plants generally open at sunset.  It grows from eastern Oregon though Idaho to Wyoming and Montana.