Cucumber pollen, SEM 

Cucumber pollen. Colored scanning electron micrograph (SEM) of pollen grains (green) from a cucumber plant (Cucumis sativus). Each pollen grain contains a male gamete (reproductive cell) that is intended to fertilize ovules or eggs (the female gametes) of another flower, initiating the formation of a seed. Cucumber plants ordinarily have both male and female flowers on the same plant, and some agent is required to transfer the pollen between flowers of the same or of different plants. The outer wall (exine) of each pollen grain is highly sculpted to aid the dispersal of the pollen grains but, as with other cucurbits, cucumber pollen is large and sticky, so pollination relies heavily on bees.