Poa infirma
Species of grass
From Wikipedia, the free encyclopedia
Poa infirma, also known as early meadow-grass[1] and weak bluegrass, is a species of grass in the genus Poa. It was first described in 1812 by German botanist Carl Sigismund Kunth from a specimen found in Colombia between Fontibón and Santa Fe, in Bogota.[2] Despite this, it is actually introduced in the Americas and is native to Mediterranean Europe, North Africa and West Asia.[3][4]
| Poa infirma | |
|---|---|
| |
Scientific classification  | |
| Kingdom: | Plantae |
| Clade: | Tracheophytes |
| Clade: | Angiosperms |
| Clade: | Monocots |
| Clade: | Commelinids |
| Order: | Poales |
| Family: | Poaceae |
| Subfamily: | Pooideae |
| Genus: | Poa |
| Species: | P. infirma |
| Binomial name | |
| Poa infirma | |
Habitat
P. infirma is typically a coastal species, found in open, trampled grassland, on cliff-tops, tracksides, picnic sites, lawns, and car parks, as well as in stabilised dunes.[5]
It can also be found inland, typically in man-made habitats with poor or sand. It is often found in pavement cracks, depressions on eroded concrete, or on gravelly substrate on edges of car parks, roads, or industrial estates.[6]
Distribution
P. infirma is native to Mediterranean Europe, North Africa and West Asia.[3][4]
It is introduced on most continents:
- Sub-Saharan Africa: Namibia and South Africa.[7]
- Australasia: New Zealand and Australia.[8][9]
- North America: Western coastline, including British Columbia, Washington, Oregon, California, and Baja California.[10][11]
- South America: Colombia, Peru, Bolivia, Chile, Argentina.[10][2]
It is unclear whether P. infirma is indigenous in China and Pakistan.[12][13]
In Britain, P. infirma has rapidly spread following human disturbance and climate change further north along the coast, as well as further inland.[1]
Identification
P. infirma has two main forms: a small, densely tufted plant with short, compact inflorescences; and a lanky plant with tall, erect culms and spreading panicles. These forms apparently correspond to soil quality, with smaller plants typically growing in poorer soil. Its leaves are strikingly yellow-green.[1]
It is very similar to Poa annua, which is probably a daughter species.[14] The two species can be differentiated by P. infirma having much smaller anthers, elongated paleas, and a yellow-green colour.[15]
Taxonomy
Poa infirma was first described in 1812 by German botanist Carl Sigismund Kunth from a specimen found in Colombia between Fontibón and Santa Fe, in Bogota.[2]
Poa annua is an allotetraploid hybrid species that is derived from P. infirma and P. supina parents around 50,000 years ago.[16] P. annua and P. infirma are often confused and are believed to form a rare sterile hybrid.[14][17][18]