Poa infirma
| Poa infirma | |
|---|---|
 | |
Scientific classification  | |
| Kingdom: | Plantae |
| Clade: | Embryophytes |
| Clade: | Tracheophytes |
| Clade: | Angiosperms |
| Clade: | Monocots |
| Clade: | Commelinids |
| Order: | Poales |
| Family: | Poaceae |
| Subfamily: | Pooideae |
| Genus: | Poa |
| Species: | P. infirma |
| Binomial name | |
| Poa infirma | |
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]
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] and it is often mistaken for P. annua unless it is closely examined.[15]
References
- 1 2 3 BSBI List 2007 (xls). Botanical Society of Britain and Ireland. Archived from the original (xls) on 2015-06-26. Retrieved 2014-10-17.
- 1 2 Kunth. "Poa infirma".
- 1 2 "Poa infirma Kunth, Nov. Gen. Sp. 1: 158. 1816 - Plazi TreatmentBank". treatment.plazi.org. Retrieved 2026-08-25.
- 1 2 "Poa infirma Kunth, Nov. Gen. Sp. 1: 158. 1816 - Plazi TreatmentBank". treatment.plazi.org. Retrieved 2026-08-25.
- ↑ "Early Meadow-grass | NatureSpot". www.naturespot.org. Retrieved 2026-08-25.
- ↑ "Early Meadow-grass identification". Botanical Society of Britain & Ireland. Retrieved 2026-08-25.
- ↑ Soreng, Robert J.; Sylvester, Steven P.; Sylvester, Mitsy D. P. V.; Clark, Vincent Ralph (2020-10-28). "New records and key to Poa (Pooideae, Poaceae) from the Flora of Southern Africa region and notes on taxa including a diclinous breeding system in Poa binata". PhytoKeys. 165: 27–50. doi:10.3897/phytokeys.165.55948. ISSN 1314-2003. PMC 7642159. PMID 33192144.
- ↑ "Poa infirma Australia".
- ↑ Connor (2000). "Poa infirma New Zealand".
- 1 2 "Occurrence search". www.gbif.org. Retrieved 2026-08-26.
- ↑ "Please verify". ucjeps.berkeley.edu. Retrieved 2026-08-26.
- ↑ "Poa infirma Pakistan".
- ↑ "Poa infirma China".
- ↑ Grass Manual Treatment
- ↑ Chester, T. Plants of Southern California: Poa annua and P. infirma
Further reading
- Takagi-Arigho, Ray (1994) Poa infirma - Flourishing? ... or Fleeing? BSBI News 65:14-18 (gives details of the plant's status and habitat in southwest England)
External links