Agrostis, commonly known as the bents or bentgrasses, is a large and nearly cosmopolitan genus of grasses in the family Poaceae, distributed throughout subarctic, temperate, and tropical montane regions on every continent. The genus was established by Carl Linnaeus in Species Plantarum (1753) and is nomenclaturally conserved. Plants of the World Online recognises 189 accepted species, while the GBIF backbone catalogues 452 descendant taxa once synonyms and infraspecific names are included; older literature commonly cites a figure of "over 100 species."
Botanically, Agrostis is placed in subfamily Pooideae, tribe Poeae, subtribe Agrostidinae. Members are slender annuals or perennials, sometimes spreading by stolons or rhizomes, with delicate panicles of small, one-flowered spikelets articulated above the glumes. The glumes are narrow, acute to acuminate, and one-veined. The lemma is shorter than to roughly equalling the glumes, rounded on the back, and either awnless or carrying a short, fine awn from the back (rarely longer than a centimetre). Paleas are characteristically thin and often reduced or absent, and the callus frequently bears a minute tuft of hairs. Leaves are long and slender, contributing to the fine-textured appearance that makes several species highly valued in cultivation.
The genus reaches its greatest diversity in cool-climate floras of the Northern Hemisphere but extends through tropical mountain ranges, the Andes, southern Africa, Australia, and New Zealand. Beyond its native range, several species have become widely naturalised on remote islands from the Crozets and Kerguelen to the Marquesas, Saint Helena, and Easter Island. In Switzerland alone, the Info Flora checklist records nine species, illustrating the genus's local complexity even within a small region.
Economically, Agrostis is one of the most important turfgrass genera. Three species — creeping bent (A. stolonifera), colonial or common bent (A. capillaris), and velvet bent (A. canina) — form the backbone of cool-season golf course turf in temperate climates. Creeping bent tolerates extremely low mowing and is preferred for putting greens and fairways, while velvet bent is prized for its exceptionally fine texture and colonial bent suits less intensively managed lawns. Beyond turf, bentgrasses occupy meadows, pastures, mountain grasslands, and disturbed ground, where their fine inflorescences and adaptability make them familiar components of the temperate grass flora.
Taxonomy
Agrostis L. was established by Carl Linnaeus in Species Plantarum (1753, p. 61) and is nomenclaturally conserved. It is placed in family Poaceae, subfamily Pooideae, tribe Poeae, subtribe Agrostidinae. Plants of the World Online accepts 189 species and lists 16 generic-level synonyms, while the GBIF backbone records 452 descendant taxa once subspecies, varieties, and synonyms are included; this discrepancy reflects the well-known taxonomic complexity of the genus, with many morphologically variable, hybridising, and historically over-described entities. Older floristic literature commonly summarises the genus as containing "over 100 species, mainly temperate and subarctic."
Distribution
The genus has a near-cosmopolitan range, occurring naturally from the subarctic through temperate latitudes and into tropical mountain systems. Native distribution spans North America (Alaska to the continental United States), Europe, Asia (Siberia to Southeast Asia), Africa (Sahara, East Africa, and southern regions), South America (especially the Andes and southern temperate zones), Australia, and New Zealand. The Swiss checklist alone records nine species, and herbarium records show extensive representation across Arizona and New Mexico. Introductions, often associated with pastoral or amenity use, have established the genus on numerous remote islands, including the Chatham Islands, Crozet Islands, Easter Island, Jamaica, Kerguelen, Macquarie Island, the Marion–Prince Edward Islands, the Marquesas, New Caledonia, Norfolk Island, Samoa, South Georgia, and Saint Helena.
Ecology
Agrostis is fundamentally a cool-climate genus, reaching greatest abundance in subarctic and temperate grasslands and extending to high-elevation tropical mountains. Species occupy meadows, pastures, alpine swards, stream margins, and disturbed open ground; the fine inflorescences and tolerance of poor, acidic soils typical of many bents have allowed them to dominate large tracts of upland pasture in regions such as the British Isles and the European Alps.
Cultivation
Agrostis is one of the most economically important genera of cool-season turfgrasses. Three species dominate cultivated use: creeping bent (A. stolonifera), colonial or common bent (A. capillaris), and velvet bent (A. canina). Creeping bent is the most widely planted on golf courses, where its aggressive stoloniferous spread and tolerance of very low mowing make it the standard choice for putting greens and fairways. Colonial bent is taller and finer-textured, better suited to lawns and lower-input situations, and takes longer to establish from seed. Velvet bent has the finest texture of all the bents, was historically favoured in European estate lawns and golf turf, and is seeing renewed interest in the United Kingdom as climate conditions shift. The shallow but dense bentgrass root system supports easy seeding and produces the smooth, uniform surface that defines high-end cool-season turf.
History
Creeping bentgrass was historically known in England as "Orcheston long grass," named for the village of Orcheston on Salisbury Plain where unusually long-growing stands were recorded. More recently, A. stolonifera was the subject of a notable genetic-engineering controversy: Scotts Miracle-Gro and Monsanto developed glyphosate-tolerant creeping bent for golf course use, but field-test pollen was detected up to 14–21 kilometres from release sites, and a US$500,000 fine was imposed in 2007 in connection with the trials.
