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. There is disagreement about its native status in North America, with some sources considering it native and others stating the Spanish Empire brought the seeds of Kentucky bluegrass to the New World in mixtures with other grasses. It is a common and incredibly popular lawn grass in North America with the species being spread over all of the cool, humid parts of the United States. In its native range, 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 has established itself as a common invasive weed across cool moist temperate climates like the Pacific Northwest and the Northeastern United States. When found on native grasslands in Canada, for example, it is considered an unwelcome exotic plant, and is indicative of a disturbed and degraded landscape.
Poa is a genus of about 570 species of grasses, native to the temperate regions of both hemispheres. Common names include meadow-grass, bluegrass, tussock, and speargrass. Poa is Greek for 'fodder'. Poa are members of the subfamily Pooideae of the family Poaceae.
Poa nemoralis, the wood bluegrass, is a perennial plant in the family Poaceae. The late-growing grass is fairly nutritious for livestock, which feed on it in the autumn, and it is used as a lawn grass for shady situations.
Poa compressa, the Canada bluegrass or flattened meadow-grass, is a perennial flattened meadow grass, similar to common meadow-grass, Poa pratensis. It is native to Europe but it can be found nearly worldwide as an introduced species. It grows in old wall tops, pavement cracks, dry stony grassland, and many types of wild habitat. It has a flattened stem, 23–30 cm tall, a close one sided panicle of grey green, with purple florets.
Poa secunda is a widespread species of perennial bunchgrass native to North and South America. It is highly resistant to drought conditions, and provides excellent fodder; and has also been used in controlling soil erosion, and as revegetator, often after forest fires. Cultivars include 'Canbar', 'Service', 'Sherman', and 'Supernova'. Historically, indigenous Americans, such as the Gosiute of Utah, have used P. secunda for food. It was originally described botanically in 1830 by Jan Svatopluk Presl, from a holotype collected from Chile by Thaddäus Haenke in 1790.
Poa bolanderi is a species of grass known by the common name Bolander's bluegrass. It is native to western North America from British Columbia to Utah to California, where it is a resident of mountain habitat, particularly pine and fir forests. It is an annual grass growing in clumps up to 60 centimeters tall. The inflorescence occupies the top 10 to 15 centimeters of the stem. It is narrow in flower, with branches appressed, growing parallel to the stem. As the fruit develops the branches spread out, becoming perpendicular to the stem, nodding, or drooping. The branches have few, sparse spikelets.
Poa bulbosa is a species of grass known by the common names bulbous bluegrass or bulbous meadow-grass. It is native to Eurasia and North Africa, but it is present practically worldwide as an introduced species. It is widespread in the United States and southern Canada. It was introduced to the eastern United States around 1906 and the western US in 1915 as a contaminant in shipments of alfalfa seed. It was intentionally planted on both the east and west coasts to control weeds and prevent erosion. Today it is a common grass across the continent and is a noxious weed in some areas. It is a sturdy, hardy, persistent, aggressive grass that easily outcompetes many other plants and becomes the dominant species in disturbed habitat types, such as overgrazed fields.
Poa confinis is a species of grass known by the common names coastline bluegrass and beach bluegrass. It is native to the coastline of western North America from British Columbia to northern California, where it grows on beaches, dunes, and other coastal habitat.
Poa cusickii is a species of grass known by the common name Cusick's bluegrass. It is native to western North America from Yukon to Colorado to eastern California, where it grows in many types of habitat, including high mountain meadows and slopes, sagebrush scrub, and forests.
Poa douglasii is a species of grass known by the common names Douglas' bluegrass and sand dune bluegrass. It is endemic to the coastline of California, where it grows in shifting sand dunes. It can be found mostly along the Central Coast and Channel Islands, and occasionally on the North Coast north of Mendocino. It is a perennial grass growing small, dense clumps up to about 30 centimeters in maximum height. It grows from a network of long rhizomes and stolons that anchor the grass to its loose sandy substrate; this network may be up to one meter long. The inflorescence is a dense, oval-shaped series of overlapping spikelets. The grass is dioecious, with male and female individuals producing different types of flowers in their inflorescences. This species, like many sand-dune endemic plants, is threatened by invasive species.
Poa glauca is a species of grass known by the common names glaucous bluegrass, glaucous meadow-grass and white bluegrass. It has a circumboreal distribution, occurring throughout the northern regions of the Northern Hemisphere. It is also known from Patagonia. It is a common grass, occurring in Arctic and alpine climates and other areas. It can be found throughout the Canadian Arctic Archipelago in many types of habitat, including disturbed and barren areas.
Poa infirma is a species of grass known by the common names early meadow-grass and weak bluegrass. It was first described from a specimen found in Colombia, but it is actually an introduced species in the Americas and is native to Europe. It grows in many types of habitat, including disturbed areas. It is very similar to Poa annua, which is probably a daughter species, and it is often mistaken for P. annua unless it is closely examined.
Poa leptocoma is a species of grass known by the common names marsh bluegrass and western bog bluegrass.
Poa macrantha is a species of grass known by the common names seashore bluegrass and large-flowered sand dune bluegrass. It is native to the west coast of North America from Alaska to northern California, where it grows in sand dunes and other beach habitat.
Poa unilateralis is a species of grass known by the common names San Francisco bluegrass, ocean-bluff bluegrass, and sea-bluff bluegrass.
P. palustris may refer to:
Poa arida is a species of grass known by the common names plains bluegrass and prairie speargrass. It is native to North America, where it occurs throughout western and central Canada and the central United States. It is most common east of the Continental Divide; specimens west are often misidentifications.
Poa paludigena is a species of grass known by the common names bog bluegrass, marsh bluegrass, slender marsh bluegrass, and Patterson's bluegrass. It is native to the northeastern United States.
