Click on the name of a different pollen below to find out more about it,
or click on the other microscope for a different view of this pollen.

Bur Oak Cattail Cocklebur Cottonwood
Dandelion Kentucky Bluegrass Pigweed Ragweed
River Birch Russian Thistle Sunflower White Pine

Kentucky Bluegrass
Poa pratensis

Grasses are the main cause of pollen allergies in the world. Kentucky bluegrass produces more pollen than any other grass in the United States. It ranks second to ragweed in causing hay fever. Grass makes pollen when it blooms. Luckily, grass that is kept mowed won't flower. In bluegrass that isn't mowed, tiny clusters of flowers rise above the grass blades in May. Each day, almost like clockwork, some of the flowers open and release their pollen into the air. The process happens at the same time every day until all the flowers in the spike have opened up and shed their pollen. Bluegrass isn't actually from Kentucky. It came from Europe with the first settlers to North America. They planted the grass in pastures to feed their livestock because it was nutritious, fast growing, and able to stand up to heavy grazers. Soon it spread to meadows and open woods. As communities grew, people planted bluegrass around their houses. Now you can find bluegrass lawns around most homes in the United States.