Poa pratensis


Poa pratensis, commonly known as Kentucky bluegrass, smooth meadow-grass, or common meadow-grass, is a perennial species of grass native to practically all of Europe, North Asia and the mountains of Algeria and Morocco. Although the species is spread over all of the cool, humid parts of the United States, it is not native to North America. The Spanish Empire brought the seeds of Kentucky bluegrass to the New World in mixtures with other grasses. 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 Pacific Northwest, and Northeastern United States. When found on native grasslands in Canada, however, it is considered an unwelcome exotic plant, and is indicative of a disturbed and degraded landscape.

Taxonomy

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.
Poa pratensis is the type species of the grass family Poaceae.
There are two ill-defined subspecies:
Poa pratensis is a herbaceous perennial plant tall. The leaves have boat-shaped tips, narrowly linear, up to long and broad, smooth or slightly roughened, with a rounded to truncate ligule long. The conical panicle is long, with 3 to 5 branches in the basal whorls; the oval spikelets are long with 2 to 5 florets, and are purplish-green or grey. They are in flower from May to July, compared to annual meadowgrass which is in flower for eight months of the year. Poa pratensis has a fairly prominent mid-vein.
The ligule is extremely short and square ended, making a contrast with annual meadowgrass and rough meadowgrass in which it is silvery and pointed. The Kentucky bluegrass is a dark green/blue compared to the apple-green color of Poa annua and Poa trivialis.
The rootstock is creeping, with runners. The broad, blunt leaves tend to spread at the base, forming close mats.

Ecology

This species is among the food plants of the caterpillars of the meadow brown and gatekeeper butterflies; the common sun beetle , Eupelix cuspidata of the leafhopper family, and Myrmus miriformis, a grassbug.

Cultivation and production

Since the 1950s and early 1960s, 90% of Kentucky bluegrass seed in the United States has been produced on specialist farms in Idaho, Oregon and Washington.
During the 1990s botanists began experimenting with hybrids of Poa pratensis and Texas bluegrass, with the goal of creating a drought and heat-resistant lawn grass.
It is famously used for the playing field of Lambeau Field in Green Bay, WI and is sewn into the field for reinforcement.

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