Pine pollen. Coloured scanning electron micrograph (SEM) of pine tree (Pinus sp.) pollen grains. Each grain consists of a pair of oval air-filled chambers attached to a granular base. This structure provides buoyancy, enabling it to be dispersed on the wind. The pollen grain contains the male gametes needed for reproduction. An allergic reaction to pollen causes hayfever (allergic rhinitis). Magnification unknown.