COMMON EVENINGPRIMROSE, Oenothera biennis L. 1, upper portion of stem showing seed pods, flowers and buds; 2, root; 3, single flower; 4, seeds. Biennial, reproducing by seeds. Produces large rosette of leaves and a fleshy root the first year. Stem the second year erect, leafy, 1 to 5 feet (0.3 to 1.5 m) tall, branching only in upper portion if at all; lower stem often tinged with purple and somewhat hairy. Leaves variable, but usually lanceolate and without petioles, lower leaves often purplish and hairy like lower stem. Flowers about 1 inch (2.5 cm) across, with 4 yellow petals, opening over a period of several weeks. Seed pods woody, cylindrical, containing many seeds. Seeds 1/16 inch (1.5 mm) long, irregular, angular, brown. Found in wasteland and fields, especially in dry or sandy soil.