Agrostis gigantea

{{Short description|Species of grass}}

{{Speciesbox

|name = Redtops

|image = Agrostis gigantea.jpeg

|genus = Agrostis

|species = gigantea

|authority = Roth, 1788

|synonyms =

• Agrostis alba{{cite web|url= http://www.illinoiswildflowers.info/grasses/plants/redtop.htm|title=Redtop|accessdate=December 17, 2007|author=John Hilty|date=November 23, 2007|work=Grasses, Sedges, and Non-Flowering Plants of Illinois|archiveurl=https://web.archive.org/web/20071212100626/http://www.illinoiswildflowers.info/grasses/plants/redtop.htm|archivedate=December 12, 2007|url-status=live}}

}}

Agrostis gigantea, known by its common names black bent{{BSBI 2007|accessdate=2014-10-17}} and redtop, is a perennial grass of the Agrostis genus.

It is native to Europe, but in the cooler areas of North America was widely used as a pasture grass until the 1940s. Although it has largely been replaced by soybeans and more palatable grasses, it still gets some use in poor soils. It was one of the grasses planted in areas disturbed by the Trans-Alaska Pipeline. It generally does well in response to fires, with the survival of rhizomes and seeds.{{cite web|url= http://www.fs.fed.us/database/feis/plants/graminoid/agrgig/all.html|title=Agrostis gigantea |work=Fire Effects Information System|publisher=United States Forest Service}}

It can be found in open woodland, rough grassland, hedgerows, roadsides and waste ground, and as a weed on arable land.

This species is similar to Agrostis stolonifera, with the key difference being that the latter has stolons. In fact the two are sometimes treated as a single species, and it is not always clear precisely what an author means by Agrostis alba or Agrostis stolonifera.

Many internet sources{{which|date=July 2023}} describe Agrostis capillaris as being the tallest of the bent species. However C E Hubbard describes its height as being {{convert|10|-|70|cm}}, whereas Agrostis gigantea's height is {{convert|40|-|120|cm}}. Marjorie Blamey, Richard and Alastair Fitter also describe black bent as being taller.{{cite book|title=Grasses|author=C E Hubbard|year=1978|publisher=Penguin Books}}{{cite book|title=Wild Flowers of Britain and Ireland|author=Marjorie Blamey, Richard and Alistair Fitter|year=2003|publisher=A. & C. Black |isbn=0-7136-5944-0}}