Poa

Kentucky bluegrass Poa pratensis, photographed by Russ Kleinman & Kelly Kindscher.

Belongs within: Pooideae.

Poa is a genus of more than 500 species of grasses, including meadow-grasses and bluegrasses, found in temperate regions of both hemispheres as well as on tropical mountains. Notable species include P. annua, annual bluegrass, which is commonly used for lawns and animal fodder.

Characters (from Zhu, Liu et al.): Annuals or perennials. Culm bases infrequently swollen, or with bulbous sheath bases; new shoots intravaginal, extravaginal, or 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, florets (1–)2–8(–10), rachilla disarticulating above glumes 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, blunt, glabrous or webbed (with a dorsal tuft of woolly hairs), 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, sometimes smooth, sometimes pilulose to villous, margins usually smooth, glabrous. Lodicules 2. Stamens 3, anthers sometimes vestigial. Ovary glabrous. Caryopsis oblong to fusiform, triangular to oval in cross section, sometimes grooved, free or adhering to the palea. 2n = 14–266. x = 7.

<==Poa
    |--P. acicularifolia W27
    |--P. aitchisonii Boiss. 1884 SS05
    |--P. alpigena O88
    |    |--P. a. ssp. alpigena O88
    |    `--P. a. ssp. staintonii O88
    |--P. ampla SF98
    |--P. anceps [incl. P. anceps var. elata, P. anceps var. foliosa non Festuca foliosa] C06
    |    |--P. a. var. anceps An27
    |    |--P. a. var. condensata Cheeseman 1906 C06
    |    |--P. a. var. debilis An27
    |    |--P. a. var. densiflora An27
    |    `--P. a. var. gracilis Cheeseman 1906 C06
    |--P. angustifolia K09
    |--P. annua GR98
    |--P. arnoldii O88
    |--P. astoni Petrie 1906 C06
    |--P. attenuata Trin. 1835 SS05
    |--P. autumnalus SF98
    |--P. bonariensis S06
    |--P. breviglumis W91
    |--P. bulbosa Linnaeus 1753 PL04
    |    |--P. b. var. bulbosa O88
    |    `--P. b. var. vivipara O88
    |--P. caespitosa [incl. P. laevis var. filifolia, P. australis var. laevis] C06
    |    |--P. c. var. caespitosa C06
    |    |--P. c. var. australis C06
    |    `--P. c. var. leioclada Hackel in Cheeseman 1906 C06
    |--P. calliopsis O88
    |--P. celsa W91
    |--P. chathamica Petrie 1902 C06
    |--P. cheesemanii Hackel 1903 C06
    |--P. ciliaris C55b
    |--P. clelandii B00b
    |--P. colensoi W91
    |    |--P. c. var. colensoi C06
    |    `--P. c. var. intermedia Cheeseman 1906 C06
    |--P. compressa C55b
    |--P. cookii SBG97
    |--P. dipsacea Petrie 1894 C06
    |--P. drummondiana OS04
    |--P. eleanorae O88
    |--P. ensiformis B00b
    |--P. eragrostis C55a
    |--P. exigua An27
    |--P. falconeri O88
    |--P. fawcettiae B00a
    |--P. flabellata [incl. Dactylis caespitosa] C06
    |--P. foliosa [=Festuca foliosa] C06
    |--P. fuegiana D03
    |--P. grisebachii Fries 1905 S06
    |--P. gunnii B00b
    |--P. hamiltoni Kirk 1895 C06
    |--P. hiemata B00a
    |--P. himalayana O88
    |--P. hirtiglumis O88
    |--P. holciformis S06
    |--P. hookeri B00b
    |--P. imbecilla [=Eragrostis imbecilla] C06
    |    |--P. i. var. imbecilla C06
    |    `--P. i. var. matthewsii (Petrie) Hackel in Cheeseman 1906 C06 (see below for synonymy)
    |--P. imperialis O88
    |--P. inconspicua Veldkamp in Royen 1979 GR98
    |--P. incrassata Petrie 1902 C06
    |--P. infirma H59
    |--P. kanaii Rajbh. 1988 SS05
    |--P. kirkii [incl. P. purpurea Kirk 1877 (n. n.)] C06
    |    |--P. k. var. kirkii C06
    |    |--P. k. var. collinsii Hackel in Cheeseman 1906 [=P. collinsii Kirk ex Petrie 1896 (n. n.)] C06
    |    `--P. k. var. mackayi (Buchanan) Hackel in Cheeseman 1906 C06
    |--P. labillardieri B00a
    |--P. langtangensis O88
    |--P. lanuginosa S06
    |--P. ligularis RJ11
    |--P. lindsayi C06
    |--P. litorosa Cheeseman 1906 [=Festuca scoparia non Poa scoparia] C06
    |--P. ludens O88
    |--P. maia W91
    |--P. maniototo Petrie 1890 C06
    |--P. maroccana GR98
    |--P. morrisii B00b
    |--P. myriantha Hackel in Stuckert 1906 S06
    |--P. nemoralis O88
    |    |--P. n. var. nemoralis D03
    |    `--P. n. var. magellanica D03
    |--P. novae-zealandiae Hack. 1903 C06
    |    |--P. n. var. novae-zealandiae C06
    |    `--P. n. var. subvestita Hack. 1903 C06
    |--P. pagophila O88
    |--P. palustris VB02
    |--P. × perinconspicua Scholz in Greuter & Raus 1998 (see below for synonymy) GR98
    |--P. poiformis P82
    |--P. polycolea O88
    |--P. polyphylla Hack. 1903 C06
    |--P. poophagorum O88
    |--P. pratensis LNB03
    |--P. pusilla Berggr. 1877 [incl. P. anceps var. minima] C06
    |--P. pygmaea W27
    |--P. queenslandica B00a
    |--P. ramosissima C06
    |--P. rodwayi B00b
    |--P. saxicola MB08
    |--P. scaberula D03
    |--P. sclerophylla Berggr. 1877 [incl. P. albida, P. anceps var. alpina] C06
    |--P. secunda CL86
    |--P. seticulmis Petrie 1902 C06
    |--P. sieberiana B00a
    |--P. sikkimensis O88
    |--P. stapfiana O88
    |--P. tenera B00a
    |--P. trivialis LNB03
    `--P. uniflora An27

Poa imbecilla var. matthewsii (Petrie) Hackel in Cheeseman 1906 C06 [=P. matthewsii Petrie 1902 C06; incl. P. anceps var. breviculmis An27, C06]

Poa × perinconspicua Scholz in Greuter & Raus 1998 [P. maroccana × P. infirma; =P. × inconspicua Scholz 1995 non Veldkamp in Royen 1979] GR98

*Type species of generic name indicated

REFERENCES

[A27] Andersen, J. C. 1927. Popular names of New Zealand plants. Transactions and Proceedings of the New Zealand Institute 57: 905–977.

[B00a] Braby, M. F. 2000a. Butterflies of Australia: their identification, biology and distribution vol. 1. CSIRO Publishing: Collingwood (Victoria).

[B00b] Braby, M. F. 2000b. Butterflies of Australia: their identification, biology and distribution vol. 2. CSIRO Publishing: Collingwood (Victoria).

[C55a] Candolle, A. de. 1855a. Géographie Botanique Raisonée: Ou exposition des faits principaux et des lois concernant la distribution géographique des plantes de l’époque actuelle vol. 1. Librairie de Victor Masson: Paris.

[C55b] Candolle, A. de. 1855b. Géographie Botanique Raisonée: Ou exposition des faits principaux et des lois concernant la distribution géographique des plantes de l’époque actuelle vol. 2. Librairie de Victor Masson: Paris.

[C06] Cheeseman, T. F. 1906. Manual of the New Zealand Flora. John Mackay, Government Printer: Wellington.

[CL86] Collins, E. I., & R. W. Lichvar. 1986. Vegetation inventory of current and historic black-footed ferret habitat in Wyoming. Great Basin Naturalist Memoirs 8: 85–93.

[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).

[GR98] Greuter, W., & T. Raus (eds.) 1998. Med-Checklist Notulae, 17. Willdenowia 28: 163–174.

[H59] Healy, A. J. 1959. Contributions to a knowledge of the adventive flora of New Zealand, no. 7. Transactions of the Royal Society of New Zealand 86 (1): 113–118.

[K09] Köhler, G. 2009. Heuschrecken (Saltatoria) und Ohrwürmner (Dermaptera) im Immissionsgebiet des Düngemittelwerkes Steudnitz/Thüringen—eine Langzeitstudie (1978–2001). Mauritiana 20 (3): 601–646.

[LNB03] Ledeganck, P., I. Nijs & L. Beyens. 2003. Plant functional group diversity promotes soil protist diversity. Protist 154 (2): 239–249.

[MB08] Maiden, J. H., & E. Betche. 1908. Notes from the Botanic Gardens, Sydney. No. 13. Proceedings of the Linnean Society of New South Wales 33: 304–319.

[OS04] Obbens, F. J., & L. W. Sage. 2004. Vegetation and flora of a diverse upland remnant of the Western Australian wheatbelt (Nature Reserve A21064). Journal of the Royal Society of Western Australia 87 (1): 19–28.

[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.

[P82] Pickard, J. 1982. Catastrophic disturbance and vegetation on Little Slope, Lord Howe Island. Australian Journal of Ecology 7: 161–170.

[PL04] Pohl, G., & I. Lenski. 2004. Zur Verbreitung und Vergesellschaftung von Pennisetum orientale Rich. in Nordeuböa (Griechenland) (Poaceae, Paniceae). Senckenbergiana Biologica 83 (2): 209–223.

[RJ11] Rising, J. D., A. Jaramillo, J. L. Copete, P. G. Ryan & S. C. Madge. 2011. Family Emberizidae (buntings and New World sparrows). In: Hoyo, J. del, A. Elliott & D. A. Christie (eds) Handbook of the Birds of the World vol. 16. Tanagers to New World Blackbirds pp. 428–683. Lynx Edicions: Barcelona.

[SF98] Saikkonen, K., S. H. Faeth, M. Helander & T. J. Sullivan. 1998. Fungal endophytes: a continuum of interactions with host plants. Annual Review of Ecology and Systematics 29: 319–343.

[SS05] Srivastava, S. K., & K. C. Sekar. 2005. Contribution to the flora of Himachal Pradesh from Pin Valley National Park. Bulletin of the Botanical Survey of India 47 (1–4): 159–162.

[SBG97] Starý, J., W. Block & P. Greenslade. 1997. Oribatid mites (Acari: Oribatida) of sub-Antarctic Heard Island. Journal of Natural History 31: 545–553.

[S06] Stuckert, T. 1906. Segunda contribución al conocimiento de las gramináceas Argentinas. Anales del Museo Nacional de Buenos Aires, serie 3, 6: 408–555.

[VB02] Vijay, S. K., & T. N. Bhardwaja. 2002. Vegetation and phenodynamics of wetlands of central Rajasthan. Journal of the Bombay Natural History Society 99 (3): 573–581.

[W27] Wall, A. 1927. Some problems of distribution of indigenuous plants in New Zealand. Transactions and Proceedings of the New Zealand Institute 57: 94–105.

[W91] Williams, P. A. 1991. Subalpine and alpine vegetation of granite ranges in western Nelson, New Zealand. New Zealand Journal of Botany 29: 317–330.

Last updated: 30 November 2017.