evening primrose Oenothera biennis Kingdom: Plantae FEATURES Division: Magnoliophyta Evening primrose is a biennial herb that grows from Class: Magnoliopsida fibrous roots. The plant is leafy and hairy. Its stems Order: Myrtales are upright, branched and often red. Basal leaves are formed in the first year of growth. Stem leaves are Family: Onagraceae arranged alternately. Each leaf is simple, lance- ILLINOIS STATUS shaped and toothed. A leaf may be six inches long and two inches wide. The yellow flowers of evening common, native primrose have four petals, each shallowly notched at the tip. The four-branched stigma has an “X” shape. The sepal tips point toward the ground. The flowers are arranged in several spikes at the stem tip. The fruit is an oblong, hairy capsule, up to two inches long, that contains tiny, red seeds. This plant may attain a height of one to six feet. BEHAVIORS Evening primrose may be found throughout Illinois. It grows in prairies, thickets, fields, roadsides and railroad rights-of-way. Flowers are produced from June through October. The flower opens toward evening and wilts the next day. The roots and leaves of the young plants are eaten by wildlife. Evening flower and plant primrose is pollinated by night-flying sphinx moths. ILLINOIS RANGE © Illinois Department of Natural Resources. 2021. Biodiversity of Illinois. Unless otherwise noted, photos and images © Illinois Department of Natural Resources. flower Aquatic Habitats none Woodland Habitats none Prairie and Edge Habitats black soil prairie; edge; sand prairie © Illinois Department of Natural Resources. 2021. Biodiversity of Illinois. Unless otherwise noted, photos and images © Illinois Department of Natural Resources..