Kentucky Blue Grass

Poa pratensis
Scientific classification
Kingdom:	Plantae
(unranked):	Angiosperms
(unranked):	Monocots
(unranked):	Commelinids
Order:	Poales
Family:	Poaceae
Genus:	Poa
Species:	P. pratensis
Binomial name
Poa pratensis L.

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 forms a valuable pasture plant, characteristic of well-drained, fertile soil. It is also used for making lawns in parks and gardens and is common in cool moist climates like the northeastern United States.

Poa pratensis was one of the many species described by Carl Linnaeus in his landmark work Species Plantarum in 1753. Poa is Greek for fodder and pratensis is derived from pratum, the Latin for meadow. The name Kentucky bluegrass derives from its flower heads, which are blue when the plant is allowed to grow to its natural height of 60 to 90 cm (2 to 3 feet).

Poa pratensis is the type species of the grass family Poaceae.

There are two ill-defined subspecies:

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).

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Wikipedia