Poa is a genus of about 500 species of grasses, native to the temperate regions of both hemispheres. Common names include meadow-grass (mainly Europe and Asia), bluegrass (mainly North America), tussock (some New Zealand species), and speargrass. Bluegrass, which has green leaves, derives its name from the seed heads which are blue when the plant is allowed to grow to its natural height of two to three feet. One species, Smooth Meadow-grass Poa pratensis, is the type species of the family Poac… (More on Poa)