Evening Primrose - introduced (*Oenothera stricta)

Family: Onagraceae (Willow-herb family).

Native of South America.

Occurrence: Moderately common roadside weed.

Identification:

• the flowers have four yellow petals, which change to orange and red
• the flowers are in a spike along the stem
• the plant has a long flowering period as the flowers open progressively along the stem
• the leaves are stalkless, and are indistinctly toothed towards the ends
• the leaves are narrow to lance-shaped.

The flowers of Evening Primrose open at night, and are fertilised by moths. The flowers darken after fertilisation.

It is an environmental weed.