Poa annua | |
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Scientific classification | |
Kingdom: | Plantae |
Clade: | Tracheophytes |
Clade: | Angiosperms |
Clade: | Monocots |
Clade: | Commelinids |
Order: | Poales |
Family: | Poaceae |
Subfamily: | Pooideae |
Genus: | Poa |
Species: | P. annua |
Binomial name | |
Poa annua | |
Poa annua, or annual meadow grass (known in America more commonly as annual bluegrass or simply poa), is a widespread low-growing turfgrass in temperate climates. Notwithstanding the reference to annual plant in its name, perennial bio-types do exist. [2] This grass originated as a hybrid between Poa supina and Poa infirma . [3] Major chromosomal rearrangements after polyploidy have contributed to variation in genome size in Poa annua. [4]
It has a slightly creeping, fibrous, rootstock. The stem grows from 15–25 cm (6-10 in.) high. It is slightly flattened, due to being folded rather than rolled.
The panicle is open and triangular shaped, 5 to 7.5 cm (2 to 3 in.) long. The spikelets are stalked, awnless, 1 to 2 cm (3/8 to 3/4 in.) long when flowering, and loosely arranged on delicate paired or spreading branches. Sometimes they are tinged purple.
The vivid green leaves are short and blunt at the tips, shaped like the prow of a small canoe. They are soft and drooping. Long sheaths clasp the stem. The leaves are smooth above and below, with finely serrated edges. Occasionally the leaves are serrated transversely.
The ligule is pointed and silvery. Compared this to Common Meadowgrass Poa pratensis , which has a squared ligule, and Poa trivialis , which has a pointed, but less silvery ligule.
The leaves are smooth above and below, with finely serrated edges. Occasionally the leaves are serrated transversely.
It is in flower all year around except for severe winters. The seeds ripen and are deposited 8 months of the year. The plant grows rapidly from seed, flowering within 6 weeks, seeding and then dying. [5]
Poa is derived from the Greek name for a type of fodder grass. [6] Annua is Latin, meaning 'annual' or 'lasting a year'. [6]
It is a common weed of cultivation, known in the Americas as annual bluegrass. [7] It occurs as a common constituent of lawns, where it is also often treated as a weed, and grows on waste ground. Many golf putting greens, including the Oakmont Country Club greens, are annual bluegrass, [8] although many courses have converted to creeping bentgrass (Agrostis stolonifera).
It has appeared on King George Island in the Antarctic South Shetland Islands as an invasive species, [9] as well as on Australia's subantarctic Heard and Macquarie Islands.
Timothy is an abundant perennial grass native to most of Europe except for the Mediterranean region. It is also known as timothy-grass, meadow cat's-tail or common cat's tail. It is a member of the genus Phleum, consisting of about 15 species of annual and perennial grasses.
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.
Elymus repens, commonly known as couch grass, is a very common perennial species of grass native to most of Europe, Asia, the Arctic, and northwest Africa. It has been brought into other mild northern climates for forage or erosion control, but is often considered a weed.
Molinia caerulea, known by the common name purple moor-grass, is a species of grass that is native to Europe, west Asia, and north Africa. It grows in locations from the lowlands up to 2,300 m (7,546 ft) in the Alps. Like most grasses, it grows best in acid soils, ideally pH values of between 3.5 and 5, however, it can continue to live under more extreme conditions, sometimes to as low as 2. It is common on moist heathland, bogs and moorland throughout Great Britain and Ireland. Introduced populations exist in northeastern and northwestern North America.
A ligule is a thin outgrowth at the junction of leaf and leafstalk of many grasses and sedges. A ligule is also a strap-shaped extension of the corolla, such as that of a ray floret in plants in the daisy family Asteraceae.
Agrostis stolonifera is a perennial grass species in the family Poaceae. It is widely used as turf for golf courses.
Cynosurus cristatus, the crested dog's-tail, is a short-lived perennial grass in the family Poaceae, characterised by a seed head that is flat on one side. It typically grows in species rich grassland. It thrives in a variety of soil types but avoids the acid and calcareous extremes of pH, and prefers well drained soils. It may be grown as an ornamental plant.
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 trivialis, is a perennial plant regarded in the US as an ornamental plant. It is part of the grass family.
Bromus hordeaceus, the soft brome, is an annual or biennial species of grass in the grass family (Poaceae). It is also known in North America as bull grass, soft cheat, and soft chess.
Agrostis capillaris, the common bent, colonial bent, or browntop, is a rhizomatous and stoloniferous perennial in the grass family (Poaceae). It is native to Eurasia and has been widely introduced in many parts of the world. Colonial bent grows in moist grasslands and open meadows, and can also be found in agricultural areas, roadsides, and invading disturbed areas.
Bromus sterilis is an annual or biennial species of bromegrass known as barren brome, poverty brome, and sterile brome.
Agrostis gigantea, known by its common names black bent and redtop, is a perennial grass of the Agrostis genus.
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 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.
Bromus commutatus, the meadow brome, is an annual or biennial species of plant in the grass family Poaceae. In the United States it is known as hairy chess.
British NVC community OV12 is one of the open habitat communities in the British National Vegetation Classification system. It is one of eight arable weed and wasteland communities of fertile loams and clays.
Lolium giganteum, giant fescue, is a woodland grass that grows on neutral to base-rich soils, often near streams or other damp places. It is native to Europe and much of Asia and has been introduced to parts of North America.