The pin and thrum of primroses

Primroses fairhaven

Primrose (Primula vulgaris) in flower at Fairhaven Woodland and Water Garden.

Last weekend I visited Fairhaven Woodland and Water Garden in South Walsham, Norfolk. While there I saw plenty of primroses (Primula vulgaris) in flower. The primrose is native to Western and Southern Europe and cultivated forms are popular in gardens.

During a field trip in Pembrokeshire as an undergraduate student I spent a couple of days studying primrose flowers. Wild primrose flowers are typically a pale yellow colour like those pictured above but white and pink forms are also seen. There are two forms of flowers, which look almost identical apart from the position of the stigma (female part) and the anthers (male part holding the pollen) in the flower tube in the centre. In “pin” flowers the stigma is positioned at the top of the tube with the anthers positioned halfway down. In “thrum” flowers the stigma is instead positioned halfway down the tube with the anthers at the top. Continue reading