Common Names in English:
infrequently swollen, or with bulbous sheath
bases; new shoots
intravaginal or extravaginal
, rarely (in China) pseudointravaginal, intravaginal but with reduced or rudimentary
lower leaf blades
and weakly differentiated prophyl. Uppermost culm leaf sheath closed from 1/20th to entire length
; ligule hyaline
, membranous or infrequently papery
; blade flat, folded, or involute
, abaxially keeled
, adaxially with 1 groove
on either side of the midvein
, apex prow-tipped. Inflorescence a terminal
panicle; branches 1-9 per node; flowers all bisexual
, or mixed bisexual and female (rarely male), with distal female flowers within spikelets
, or with partially to wholly female spikelets or inflorescences. Spikelets laterally compressed
(1-) 2-8(-10), rachilla disarticulating
and between florets, uppermost floret vestigial; vivipary sometimes present; glumes mostly strongly keeled, unequal, or subequal
, lower glume 1- or 3-veined, upper glume 3(or 5) -veined; lemmas laterally compressed, usually distinctly keeled, 5(-7) -veined, distal margins and apex membranous, apex awnless, rarely minutely mucronate
; floret callus short, truncate
(with a dorsal tuft of woolly
), rarely with a line
of hairs around base of lemma; palea subequal or infrequently to 2/3 as long as lemma, not gaping
, keels green, distinctly separated, usually scabrid
in Poa sect. Micrantherae, sometimes pilulose to villous
usually smooth, glabrous. Lodicules 2. Stamens 3, anthers
sometimes vestigial. Ovary glabrous. Caryopsis oblong
, triangular to oval
, sometimes grooved
or adhering to the palea. 2n = 14-266. x = 7.
More than 500 species: throughout Arctic and N and S temperate regions and extending to most subtropical and tropical mountains, in habitats such as temperate forests, mountain slopes , grasslands, wetlands, steppes , alpine areas and tundra , deserts, and around human habitation, on acidic to sub-basic or subsaline, dry to wet soils, from sea level to the upper limits of vegetation; 81 species (14 endemic, at least one introduced ) in China.
Poa includes many species useful and important for forage , soil stabilization, and lawns, and several widespread weeds . Five of six recognized subgenera are present in China. (1) Poa subg. Arctopoa: stout plants with thick rhizomes, scabrid to ciliate lemma margins, and glabrous calluses, found in subsaline to subalkaline wetlands. (2) Poa subg. Ochlopoa: plants with bulbous sheathed culm bases (spikelets then often viviparous), or if not bulbous then commonly quite smooth throughout, with shortly villous palea keels and no callus hairs, sometimes annuals. (3) Poa subg. Pseudopoa: slender annuals with scabrid-angled panicle branches, shortish glumes, uppermost culm sheaths closed for 1/15-1/10 their length, glabrous calluses, and scabrid rachillas. (4) Poa subg. Poa: the largest and most diverse subgenus , including annuals and perennials, with or without rhizomes, but generally with the uppermost culm sheaths closed for over 1/4 their length. (5) Poa subg. Stenopoa: commonly tufted perennials generally with the uppermost culm sheaths closed for only 1/15-1/5(-1/4) their length, with mainly extravaginal shoots, mostly without rhizomes, mostly with panicle branches that are scabrid angled from the base, and with 3-veined first glumes.
Some species have races with florets that develop into bulbils that can readily send down roots as soon as they drop from the inflorescence (i.e. , they are viviparous). Viviparous spikelets often have fairly normal-looking proximal florets. Pubescence on the lemmas and calluses of such florets is often poorly developed relative to that in normal spikelets, or absent. Identification is easiest with plants having normal spikelets.
Hybridization and facultative apomixis are common in some subgenera, especially Poa subg. Poa and P. subg. Stenopoa, and the vast majority of species studied are polyploid.
- Whittaker & Margulis,1978
- Haeckel, 1866
- Cavalier-Smith, 1981
- Sinnott, 1935 ex Cavalier-Smith, 1998
- Vascular Plants
- (Auct.) Cavalier-Smith, 1998
- Brongniart, 1843
- Takhtajan, 1967
- Superorder: Juncanae () - Takhtajan, 1967
- Subclass: Commelinidae () - Takhtajan, 1967
- Class: Spermatopsida () - Brongniart, 1843
- Infraphylum: Angiospermae () - Auct.
- Subphylum: Euphyllophytina () - (Auct.) Cavalier-Smith, 1998
- Phylum: Tracheophyta () - Sinnott, 1935 ex Cavalier-Smith, 1998 - Vascular Plants
- Subkingdom: Viridaeplantae () - Cavalier-Smith, 1981
- Kingdom: Plantae () - Haeckel, 1866 - Plants
Status: Accepted Name
Last scrutiny: 15-Mar-2000
Members of the genus Poa
ZipcodeZoo has pages for 106 species, subspecies, varieties, forms, and cultivars in this genus. Here are just 100 of them:
P. abbreviata (Northern Bluegrass) · P. alpina (Alpine Bluegrass) · P. alpina f. vivipara (Alpine Bluegrass) · P. alsodes (Grove Bluegrass) · P. annua (Annual Blue Grass) · P. annua f. reptans (Creeping Bluegrass) · P. arachnifera (Texas Blue Grass) · P. arctica grayana (Arctic Bluegrass) · P. arida (Plains Bluegrass) · P. arnowiae (Wasatch Bluegrass) · P. atropurpurea (San Bernardino Bluegrass) · P. autumnalis (Autumn Bluegrass) · P. badensis (Baden´s Bluegrass) · P. bigelovii (Bigelow Bluegrass) · P. bolanderi (Bolander's Bluegrass) · P. bulbosa (Bulbous Blue Grass) · P. capillaris (Lace Grass) · P. chaixii (Broadleaf Bluegrass) · P. chapmaniana (Chapman's Bluegrass) · P. chinensis (Chinese Sprangletop) · P. cita (Silvery Tussock-Grass) · P. colensoi (Blue Tussock) · P. compressa (Canada Bluegrass) · P. confinis (Coastline Bluegrass) · P. cornae (St. John's Bluegrass) · P. curtifolia (Little Mountain Bluegrass) · P. cusickii epilis (Cusick's Bluegrass) · P. cusickii purpurascens (Cusick's Bluegrass) · P. cuspidata (Early Bluegrass) · P. douglasii (Douglas' Bluegrass) · P. douglasii douglasii (Douglas' Bluegrass) · P. eminens (Largeflower Speargrass) · P. fendleriana albescens (Mutton Grass) · P. fendleriana longiligula (Muttongrass) · P. fernaldiana fernaldiana (Wavy Bluegrass) · P. gaspensis (Gaspe Peninsula Bluegrass) · P. glauca (Glaucous Bluegrass) · P. hartzii (Hartz Bluegrass) · P. hartzii hartzii (Hartz's Bluegrass) · P. howellii (Howell's Bluegrass) · P. hybrida (Hybrid Meadow Grass) · P. infirma (Weak Bluegrass) · P. interior interior (Inland Bluegrass) · P. keckii (Keck's Bluegrass) · P. kelloggii (Kellogg's Bluegrass) · P. labillardieri (Blue Tussock Grass) · P. lanata var. lanata (Wool Bluegrass) · P. lanata var. vivipara (Wool Bluegrass) · P. laxa (Wavy Bluegrass) · P. laxiflora (Looseflower Bluegrass) · P. leibergii (Leiberg's Bluegrass) · P. leptocoma (Bog Bluegrass) · P. lettermanii (Letterman Bluegrass) · P. limosa (Lassen County Bluegrass) · P. macrantha (Seashore Bluegrass) · P. macrocalyx (Largeglume Bluegrass) · P. mannii (Mann's Bluegrass) · P. marcida (Withered Bluegrass) · P. napensis (Napa Bluegrass) · P. nemoralis (Forest Blue Grass) · P. nervosa (Wheeler Bluegrass) · P. nervosa var. nervosa (Nerved Bluegrass) · P. occidentalis (New Mexico Bluegrass) · P. pallida (Cusick's Bluegrass) · P. paludigena (Bog Bluegrass) · P. palustris (Fowl Blue Grass) · P. paucispicula (Alaska Bluegrass) · P. piperi (Piper's Bluegrass) · P. porsildii (Porsild's Bluegrass) · P. pratensis (Kentucky Bluegrass) · P. pratensis angustifolia (Narrow-Leaf Meadow Grass) · P. pratensis colpodea (Kentucky Bluegrass) · P. pratensis pratensis (Kentucky Bluegrass) · P. pratensis 'Greenplay' (Meadow Grass 'greenplay') · P. pratensis 'Kaitos' (Meadow Grass 'kaitos') · P. pratensis 'Scotts Pure Premium' (Kentucky Bluegrass Mix) · P. pringlei (Pringle's Bluegrass) · P. pseudoabbreviata (Shortcoal Bluegrass) · P. reflexa (Nodding Bluegrass) · P. rhizomata (Rhizome Bluegrass) · P. saltuensis (Oldpasture Bluegrass) · P. sandvicensis (Hawai'i Bluegrass) · P. secunda (Big Bluegrass) · P. secunda subsp. secunda (Big Bluegrass) · P. sieberiana (Grey Tussock-Grass) · P. sierrae (Sierra Bluegrass) · P. siphonoglossa (Kauai Bluegrass) · P. stebbinsii (Stebbin's Bluegrass) · P. stenantha (Largesprout Bluegrass) · P. strictiramea (Big Bend Bluegrass) · P. suksdorfii (Western Bluegrass) · P. supina (Bluegrass) · P. sylvestris (Woodland Bluegrass) · P. tenera (Slender Tussock-Grass) · P. tenerrima (Delicate Bluegrass) · P. tolmatchewii (Siberian Bluegrass) · P. tracyi (Tracy's Bluegrass) · P. trivialis (Rough Bluegrass) · P. trivialis trivialis (Rough Bluegrass) · P. trivialis 'Winterplay' (Winterplay Rough Bluegrass)
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- 1997 IUCN red list of threatened plants Cambridge: IUCN, World Conservation Union, 1998 url p. 664.
- Contributions from the United States National Herbarium 30 1957 Washington, D.C.: Smithsonian Institution Press, 1890- url p. 383.
- Memoirs of the Bernice Pauahi Bishop Museum of Polynesian Ethnology and Natural History. Honolulu: [Bishop Museum Press], 1899-1949. url , , , , p. 117, p. 119, p. 121, p. 229.
- The grasses of Hawaii, by A. S. Hitchcock. Honolulu, Hawaii, Bishop Museum Press, 1922. url , , p. 19, p. 21, p. 23.
- Bisby, F.A., Y.R. Roskov, M.A. Ruggiero, T.M. Orrell, L.E. Paglinawan, P.W. Brewer, N. Bailly, J. van Hertum, eds (2007). Species 2000 & ITIS Catalogue of Life: 2007 Annual Checklist. Species 2000: Reading, U.K.
- Brands, S.J. (comp.) 1989-present. The Taxonomicon. Universal Taxonomic Services, Zwaag, The Netherlands. Accessed January 13, 2012.
- Global Biodiversity Information Facility. Accessed February 28, 2008. http://www.gbif.org Mediated distribution data from provider.
- Ruggiero M., Gordon D., Bailly N., Kirk P., Nicolson D. (2011). The Catalogue of Life Taxonomic Classification, Edition 2, Part A. In: Species 2000 & ITIS Catalogue of Life: 2011 Annual Checklist (Bisby F.A., Roskov Y.R., Orrell T.M., Nicolson D., Paglinawan L.E., Bailly N., Kirk P.M., Bourgoin T., Baillargeon G., Ouvrard D., eds). DVD; Species 2000: Reading, UK.
- USDA, ARS, National Genetic Resources Program. Germplasm Resources Information Network - (GRIN) [Online Database]. National Germplasm Resources Laboratory, Beltsville, Maryland. URL (April 30, 2008)
- USDA, NRCS. 2005. The PLANTS Database, Version 3.5 (http://plants.usda.gov). National Plant Data Center, Baton Rouge, LA 70874-4490 USA.
Accessed through GBIF Data Portal February 28, 2008:
- USDA PLANTS: USDA PLANTS Database
- Biodiversity Heritage Library NamebankID: 2661266
- Catalogue of Life Accepted Name Code: ITS-41169
- Globally Unique Identifier: urn:lsid:ipni.org:names:418059-1
- GRIN Nomen Number: 320142
- Integrated Taxonomic Information System (ITIS) Taxonomic Serial Number (TSN): 41169
- U.S. Fish and Wildlife Service Species Identifier: Q2GQ
- U.S.D.A. Plant Symbol: POSI
- Zipcode Zoo Species Identifier: 57142