"Pollen grains
MAURIZIO DE ANGELIS
Illustration of pollen grains being released from a flower in the Asteraceae family. Asteraceae is one of the largest families of flowering plants and is commonly known as the aster, daisy, sunflower or composite family. Pollen grains contain the male sperm cell and are produced in the anther, one of the male parts of the flower. They are carried to other flowers – primarily by insects, birds and the wind – so flowering plants can reproduce. They look like fine dust and are a common cause of hay fever or seasonal allergies. Pollen grains come in all shapes and sizes, but they are usually between 0.01 and 0.1 mm in size."