Pollen grains from different plants, illustration - stock illustration

Pollen grains from different plants, computer illustration. Pollen grain size, shape and surface texture differ from one plant species to another, as seen here. The outer wall (exine) of the pollen in many plant species is highly sculpted which may assist in wind, water or insect dispersal. This pollen sculpting is also used by botanists to recognise plant species. Pores in the pollen wall help in water regulation and germination. These reproductive male spores produced by seed plants contain the male gametes. Pollen fertilises the female egg, with subsequent formation of plant seeds.