The common flower powder is sago size, which is actually a pollen ball composed of thousands of pollen grains. Each pollen is very tiny and invisible to the naked eye. It must be visible by means of an electron microscope. Different plants have different sizes and shapes of pollen, so pollen can be used to identify the species of plants. Most of the pollen is tennis-shaped, long-spherical, and irregular; pollen is mostly 10 to 60 microns in size.
Under the microscope, the same-grained pollen can be seen in two different shapes, called the equatorial plane and the polar surface. The surface of the pollen grains is not smooth, some of them are called ridges, some are called ditch, and some are distributed. Some pores are sag, called germination holes, and the pollen tube sprouts from the germination hole.
Outside the pollen grains is a hard outer wall called the pollen wall. The interior contains inclusions of various nutrients and germ cells. The inclusions are separated from the pollen wall by a membrane.