Poa

Kentuck 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.

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 FST81
    |    |--P. a. var. anceps An27
    |    |--P. a. var. breviculmis An27
    |    |--P. a. var. debilis An27
    |    |--P. a. var. densiflora An27
    |    `--P. a. var. elata An27
    |--P. annua GR98
    |--P. arnoldii O88
    |--P. astonii R85
    |--P. attenuata Trin. 1835 SS05
    |--P. autumnalus SF98
    |--P. breviglumis W91
    |--P. bulbosa Linnaeus 1753 PL04
    |    |--P. b. var. bulbosa O88
    |    `--P. b. var. vivipara O88
    |--P. caespitosa An27
    |--P. calliopsis O88
    |--P. celsa W91
    |--P. chathamica An27
    |--P. ciliaris C55b
    |--P. colensoi W91
    |    |--P. c. var. colensoi An27
    |    `--P. c. var. intermedia An27
    |--P. compressa C55b
    |--P. dipsacea Al27
    |--P. drummondiana OS04
    |--P. eleanorae O88
    |--P. eragrostis C55a
    |--P. exigua An27
    |--P. falconeri O88
    |--P. flabellata R85
    |--P. foliosa [=P. anceps var. foliosa] An27
    |--P. fuegiana D03
    |--P. himalayana O88
    |--P. hirtiglumis O88
    |--P. imbecilla An27
    |--P. imperialis O88
    |--P. inconspicua Veldkamp in Royen 1979 GR98
    |--P. infirma H59
    |--P. kanaii Rajbh. 1988 SS05
    |--P. kirkii An27
    |    |--P. k. var. kirkii An27
    |    `--P. k. var. mackayi An27
    |--P. langtangensis O88
    |--P. landsayi An27
    |--P. litorosa WH02
    |--P. ludens O88
    |--P. maia W91
    |--P. maroccana GR98
    |--P. nemoralis O88
    |    |--P. n. var. nemoralis D03
    |    `--P. n. var. magellanica D03
    |--P. novae-zealandiae W91
    |--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. poophagorum O88
    |--P. pratensis LNB03
    |--P. pusilla An27
    |--P. pygmaea W27
    |--P. scaberula D03
    |--P. sclerophylla An27
    |--P. secunda CL86
    |--P. sikkimensis O88
    |--P. stapfiana O88
    |--P. subvestita W91
    |--P. trivialis LNB03
    `--P. uniflora An27

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

[Al27] Allan, H. H. 1927. The vegetation of Mount Peel, Canterbury, New Zealand. Part 2. – The grassland and other herbaceous communities. Transactions and Proceedings of the New Zealand Institute 57: 73-89.

[An27] Andersen, J. C. 1927. Popular names of New Zealand plants. Transactions and Proceedings of the New Zealand Institute 57: 905-977.

[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.

[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 Reports of the Princeton University Expeditions to Patagonia, 1896-1899, vol. 8 – Botany (W. B. Scott, ed.) pp. 1-34. The University: Princeton (New Jersey).

[FST81] Falla, R. A., R. B. Sibson & E. G. Turbott. 1981. Collins Guide to the Birds of New Zealand and Outlying Islands 2nd ed. with addenda. Collins: Auckland.

[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.

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

[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 The Himalayan Plants vol. 1 (H. Ohba & S. B. Malla, eds) 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.

[R85] Robertson, C. J. R. (ed.) 1985. Reader’s Digest Complete Book of New Zealand Birds. Reader’s Digest: Sydney.

[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.

[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.

[WH02] Worthy, T. H., & R. N. Holdaway. 2002. The Lost World of the Moa: Prehistoric life of New Zealand. Indiana University Press: Bloomington (Indiana).

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