Poa pratensis

Poa pratensis, commonly known as Kentucky Bluegrass, Smooth Meadow-grass, or Common Meadow-grass, is a perennial species of grass native to Europe, Asia, North America, and northern Africa.

Poa pratensis is a herbaceous perennial plant 30–70 centimetres (12–28 in) tall. The leaves have boat-shaped tips, narrowly-linear, up to 20 centimetres (8 in) long and 3–5 millimetres (0.12–0.20 in) broad, smooth or slightly roughened, with a rounded to truncate ligule 1–2 millimetres (0.039–0.079 in) long. The conical panicle is 5–20 centimetres (2–8 in) long, with 3 to 5 branches in the basal whorls; the oval spikelets are 3–6 millimetres (0.12–0.24 in) long with 2 to 5 florets, and are purplish-green or grey. They are in flower from May to July, compared to Annual Meadowgrass (Poa annua) which is in flower for eight months of the year. Poa pratensis has a fairly prominent mid vein [center of the blade]

The ligule is extremely short and square ended, making a contrast with Annual Meadowgrass (Poa annua) and Rough Meadowgrass (Poa trivialis) in which it is silvery and pointed. The Kentucky bluegrass is a dark green compared to the apple green color of poa annua and poa trivialis.

References:

The Plant List  GRIN (In bold at the top)  Flora of Pakistan  Annonated checklist of the flowering plants of Nepal  Flora of China 

Wikipedia