Evening primrose (Oenothera biennis)
 
 
evening primrose

Evening primrose belongs to the Onagraceae (Evening primrose) family.  It is a biennial or short-lived perennial plant.  The plants are up to 9 inches tall with alternate leaves and often reddish-tinged stems.  The leaves are hairy on both sides.  Flowers are stalkless in elongate clusters along the upper stems, with a single flower at the base of each small leaflike bract.  The flowers spring open from bud to full bloom within minutes in the evening and smell like creosote which attracts moths.  Evening primrose is found in fields and along roadsides from June through November.

 

Additional information about this plant may be found at the USDA PLANTS Database:

http://plants.usda.gov/java/profile?symbol=OEBI