Poa

Common names include meadow-grass (mainly in Europe and Asia), bluegrass (mainly in North America), tussock (some New Zealand species), and speargrass.

[3][4][5][6][7] 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 (0.6 to 0.9 meters).

The leaves are narrow, folded or flat, sometimes bristled, and with the basal sheath flattened or sometimes thickened, with a blunt or hooded apex and membranaceous ligule.

Kentucky bluegrass (Poa pratensis) is the most extensively used cool-season grass used in lawns, sports fields, and golf courses in the United States.

[15] According to second-century physician Galen, the roots of certain species are good for treating fresh wounds and bleeding.

"Bluegrass": The seed pods go from green to purplish blue to brown. During the purplish blue phase the seed stems have a navy-blue coating.
Poa trivialis (rough meadow-grass), showing the ligule structure