Daisy pollen (Bellis perennis) Coloured scanning electron micrograph (SEM) of pollen grains of a common Daisy (Bellis perennis). The outer wall (exine) has many small spiky projections. These get caught in the body hairs of insects. The insects then fly to other flowers to feed and so pollen is transferred. Pollen contains the male reproductive cells of a plant. When the pollen grain, containing the male gametes, lands on the stigma of a flower, it germinates.