Timothy grass pollen (Phleum pratense) Science Image

Ref: p00597a



Timothy grass pollen. Coloured scanning electron micrograph (SEM) of a pollen grain from Timothy grass, Phleum pratense, also known as cat's-tail. This pollen is very light with a smooth outer wall (exine); both features assist wind dispersal. Each Timothy grass pollen grain possesses a single pore which facilitates germination of the pollen. It may also be involved in water regulation and control of compatibility between the pollen and stigma of the pollinated flower. Timothy grass flowers in the summer and its pollen is a major cause of hay fever (allergic rhinitis and pollenosis). Magnification: x 1150 at 5x7cm size.