yellow evening-primrose, more...
[Calylophus australis Towner & P.H.Raven, more]
Etymology: Calylophus: Caly Greek for calyx; lophos for "the back of the neck; crest of a hill or helmet"
Plants: erect, perennial, to 24" tall forb; stems usually clustered, often woody at the base
Leaves: many, narrowly oblong, often toothed
Flowers: yellow, 4-parted, 1/3"-1" wide, stalkless, sepals with sharply raised midrib, 8 stamens, stigma shield-shaped; solitary from the upper leaf axil; blooms June-July
Habitat: dry; prairies, plains, bluffs
Conservation Status: Special Concern