Pollen consists of plant male gametes that pass through the air either on vectors or by wind currents. The photomicrograph below illustrates a mixture of stained pollen grains illuminated by the Hoffman modulation contrast technique.

One of the most unusual features of this photomicrograph is the medium gray background produced by the Hoffman technique. This background color is explained in detail in our discussion of Hoffman Modulation Contrast and is present in all "brightfield" photomicrographs taken of both stained and unstained specimens using the technique.