Belongs within: Pooideae.
Agrostis, the bentgrasses, is a genus of about 200 species of grasses found in temperate and tropical montane regions of the Northern Hemisphere. Many bentgrasses are widely used in lawns. These include the creeping bentgrass A. stolonifera, which is native to Eurasia and northern Africa and has been widely introduced in other parts of the world such as North America. Agrostis stolonifera differs from colonial bentgrass A. capillaris, another widely introduced Eurasian species, in having longer ligules, inflorescences with primary branches mostly ascending, and crowded, overlapping spikelets (Hickman 1993).
Characters (from Lu & Phillips): Annuals or perennials, tufted or sometimes with rhizomes or stolons. Leaf blades linear to filiform or setaceous, flat or rolled; ligule membranous. Inflorescence a panicle, open to contracted or spikelike. Spikelets with 1 floret, small, often gaping, without rachilla extension; rachilla disarticulating above glumes; glumes persistent, longer than floret, subequal or lower a little longer, membranous, 1-veined, apex subacute to acuminate; floret callus glabrous or shortly pilose; lemma oblong to elliptic, thinner than glumes, often hyaline, 5-veined, rounded on back, glabrous or hairy, lateral veins sometimes excurrent, awnless or awned from back, apex truncate or toothed; awn usually geniculate, sometimes weakly so or straight when short; palea shorter than lemma, sometimes very small. Stamens 3. Caryopsis oblong, sulcate on ventral side.
<==Agrostis [incl. Trichodium]B78
|--A. aemula Br. 1810G52 [=Calamagrostis aemulaB78, Deyeuxia aemulaG52]
|--A. avenaceaGK00 (see below for synonymy)
| |--A. a. var. avenaceaC06
| |--‘Deyeuxia forsteri’ var. aristataB78
| |--‘Deyeuxia forsteri’ var. humilior Hack. in Cheeseman 1906 [incl. Agrostis striata Col. 1889]C06
| |--‘Deyeuxia forsteri’ var. laeviglumisB78
| |--‘Deyeuxia forsteri’ var. littoralis Hack. in Cheeseman 1906C06
| |--‘Deyeuxia forsteri’ var. lyallii Hack. in Cheeseman 1906 [=Agrostis lyallii]C06
| |--‘Deyeuxia forsteri’ var. micrathera Hack. in Cheeseman 1906C06
| |--‘Deyeuxia forsteri’ var. pilosa Cheeseman 1906 [=Agrostis pilosa]C06
| `--‘Deyeuxia forsteri’ var. semiglabra Hack. in Cheeseman 1906C06
|--A. blasdalei [incl. A. blasdalei var. marinensis]H93
|--A. breviglumisM89
|--A. bromidioidesS06
|--A. caninaC06
|--A. capillarisH93 [incl. A. tenuisH93, A. vulgarisG52]
|--A. cylindraceaB02
|--A. densiflora [incl. A. californica, A. clivicola, A. clivicola var. punta-reyensis]H93
|--A. drummondiana (Steud.) Vickery 1941 [=Dichelachne drummondiana, Deyeuxia drummondiana]G52
|--A. dyeri Petrie 1890C06
| |--A. d. var. dyeriC06
| |--A. d. var. aristata Hack. in Cheeseman 1906C06
| `--A. d. var. delicatior Hack. in Cheeseman 1906C06
|--A. elliottiana [incl. A. exigua]H93
|--A. exarata [incl. A. ampla, A. longiligula var. australis, A. longiligula, A. exarata var. monolepis]H93
|--A. gigantea [incl. A. nigra]V72
|--A. hackelii Fries 1905S06
| |--A. h. f. hackeliiS06
| `--A. h. f. viridiflora Hackel in Stuckert 1906S06
|--A. halliiH93
|--A. hendersonii [=A. monophylla var. hendersonii]H93
|--A. hookerianaO88
|--A. hoveriH93
|--A. humilisH93
|--A. hyemalisV72
| |--A. h. f. hyemalisV72
| `--A. h. f. setigeraV72
|--A. idahoensisH93
|--A. inaequiglumisO88
|--A. infirmaH03
| |--A. i. var. infirmaH03
| `--A. i. var. remotaH03
|--A. magellanicaL85 [incl. A. antarcticaC06, A. multicaulisC06]
|--A. microphylla [incl. A. aristiglumis, A. microphylla var. intermedia]H93
|--A. montevidensis [=A. canina var. montividensis; incl. A. trichotoma Nees apud Trin. 1845]S06
| |--A. m. var. montevidensisD03
| `--A. m. var. submuticaD03
|--A. muelleriC06 [incl. A. gelida Muell. 1855B78, A. subulataC06]
| |--A. m. var. muelleriC06
| `--A. m. var. paludosa Hack. in Cheeseman 1906C06
|--A. munroanaO88
|--A. muscosa Kirk 1881 [incl. A. aemula var. spathacea Berggr. 1877, A. spencei Kirk 1897 (n. n.)]C06
|--A. nanaS06
| |--A. n. var. nanaS06
| `--A. n. var. aristata non A. dyeri var. aristata Hack. in Cheeseman 1906S06
|--A. nervosaO88
|--A. oregonensisH93
|--A. pallens [incl. A. diegoensis, A. lepida]H93
|--A. peninsularisS03
|--A. perennansV72
|--A. petriei Hack. 1903C06
| |--A. p. var. petrieiC06
| `--A. p. var. mutica Hack. in Cheeseman 1906C06
|--A. plebeia Br. 1810G52 [=Deyeuxia plebeiaB78; incl. Didymochaeta australisB78]
|--A. pilosulaS03
|--A. preissii (Nees) Vickery 1941G52 (see below for synonymy)
|--A. pulchella Kunth. 1829S06
| |--A. p. f. pulchellaS06
| |--A. p. f. purpurascens [=A. scabra f. purpurascens]S06
| `--A. p. f. virescens [=A. scabra f. virescens]S06
|--A. rigidaC06
|--A. scabraH93 (see below for synonymy)
| |--A. s. var. scabraB78
| `--A. s. var. elatiorB78
|--A. stoloniferaH93 (see below for synonymy)
|--A. sylvaticaS00
|--A. tandilensis [incl. A. kennedyana]H93
|--A. tenella Petrie 1890C06
|--A. thurberianaH93
|--A. variabilisH93
|--A. venusta Trin. 1850G52
`--A. viridisH93 [incl. A. semiverticillataH93, A. verticillataG52]
Agrostis avenaceaGK00 [=Calamagrostis avenaceaG52; incl. Ag. debilisB78, Avena filiformisC06, Agrostis forsteriC06, Deyeuxia forsteriG52, Ag. retrofractaB78, Lachnagrostis retrofractaB78, Ag. semibarbataB78, Calamagrostis willdenowiiB78, Lachnagrostis willdenowiiB78]
Agrostis preissii (Nees) Vickery 1941G52 [=Lachnagrostis preissiiG52, Deyeuxia forsteri var. preissiiB78; incl. Agrostis solandriG52]
Agrostis scabraH93 [=Deyeuxia scabraC06; incl. A. contractaB78, A. decipiensB78, Cinna decipiensB78, A. distansB78, A. scabra var. geminataH93, A. intricataB78, A. laxifloraB78, Trichodium laxiflorumB78, A. parvifloraB78, A. rudisB78, Calamagrostis rudisB78, A. hyemalis var. tenuis non A. tenuisV72]
Agrostis stoloniferaH93 [incl. A. stolonifera var. compactaV72, A. alba var. majorH93, A. stolonifera var. majorV72, A. alba var. palustrisH93, A. stolonifera var. palustrisV72]
*Type species of generic name indicated
References
[B78] Bentham, G. 1878. Flora Australiensis: A description of the plants of the Australian Territory vol. 7. Roxburghiaceae to Filices. L. Reeve & Co.: London.
[B02] Bosc, C. 1802. Description d’un nouvel agrostis. Bulletin des Sciences, par la Societé Philomathique de Paris 1 (Bulletin de la Société Philomathique, a ses correspondans): 12′.
[C06] Cheeseman, T. F. 1906. Manual of the New Zealand Flora. John Mackay, Government Printer: Wellington.
[D03] Dusén, P. 1903. The vegetation of western Patagonia. In: Scott, W. B. (ed.) Reports of the Princeton University Expeditions to Patagonia, 1896–1899 vol. 8. Botany pp. 1–34. The University: Princeton (New Jersey).
[G52] Gardner, C. A. 1952. Flora of Western Australia vol. 1 pt 1. Gramineae. William H. Wyatt: Perth.
[GK00] Gibson, N., & G. J. Keighery. 2000. Flora and vegetation of the Byenup-Muir reserve system, south-west Western Australia. CALMScience 3 (3): 323–402.
[H03] Heads, M. 2003. Ericaceae in Malesia: vicariance biogeography, terrane tectonics and ecology. Telopea 10 (1): 311–449.
[H93] Hickman, J. C. (ed.) 1993. The Jepson Manual: Higher Plants of California. University of California Press: Berkeley (California).
[L85] Luxton, M. 1985. Cryptostigmata (Arachnida: Acari)—a concise review. Fauna of New Zealand 7: 1–106.
[M89] Maiden, J. H. 1889. Notes on the geographical distribution of some New South Wales plants, compiled from information supplied by W. Bauerlen, and from some diagnoses by Baron von Mueller, K.C.M.G., F.R.S., &c. Proceedings of the Linnean Society of New South Wales, series 2, 4 (1): 107–112.
[O88] Ohba, H. 1988. The alpine flora of the Nepal Himalayas: an introductory note. In: Ohba, H., & S. B. Malla (eds) The Himalayan Plants vol. 1. The University Museum, University of Tokyo, Bulletin 31: 19–46.
[S00] Siddiqi, M. R. 2000. Tylenchida: Parasites of plants and insects 2nd ed. CABI Publishing: Wallingford (UK).
[S03] Singh, J. N. 2003. Grasses and their hydro-edaphic characteristics in the grassland habitat of Nilgiris Biosphere Reserve, Tamil Nadu. Bulletin of the Botanical Survey of India 45: 143–164.
[S06] Stuckert, T. 1906. Segunda contribución al conocimiento de las gramináceas Argentinas. Anales del Museo Nacional de Buenos Aires, serie 3, 6: 409–555.
[V72] Voss, E. G. 1972. Michigan Flora. Part I. Gymnosperms and Monocots. Cranbrook Institute of Science and University of Michigan Herbarium.