Hairy evening-primrose (Oenothera villosa ssp. strigosa) belongs to Onagraceae (the Evening primrose family). It is a biennial herb that is distributed to central and western North America. This herb grows in prairies, hillsides, open woodlands and waste places, and up to a height of 90-120 cm. The plant is basal rosette forms in first year, erect, stiff stem in second. The leaves are lanceolate to elliptic, alternate, hairy stem leaves with wavy edges. The yellow flowers bloom in the evening from June to September. They are four-petaled, occasionally becoming orange with age.