Poales

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Poales
Temporal range: Late Cretaceous - Recent (but see text) 66–0Ma
Wheat field.jpg
Common wheat (Triticum aestivum)
Scientific classification
Kingdom: Plantae
(unranked): Angiosperms
(unranked): Monocots
(unranked): Commelinids
Order: Poales
Small[1]
families

See text

The Poales are a large order of flowering plants in the monocotyledons, and includes families of plants such as the grasses, bromeliads, and sedges. Sixteen plant families are currently recognized by botanists to be part of Poales.

The earliest fossils attributed to the Poales date to the late Cretaceous period about 66 million years ago, though some studies (e.g., Bremer, 2002) suggest the origin of the group may extend to nearly 115 million years ago, likely in South America. The earliest known fossils include pollen and fruits. The flowers are typically small, enclosed by bracts, and arranged in inflorescences (except in the genus Mayaca, with solitary terminal flowers). The flowers of many species are wind pollinated; the seeds usually contain starch. The APG III system (2009) accepts the order and places it in a clade called commelinids, in the monocots.[1] It uses this circumscription:[1]

The earlier APG system (1998) adopted the same placement, although it used the spelling "commelinoids", and used the following circumscription (i.e., it did not include the plants in families Bromeliaceae and Mayacaceae in the order):

  • order Poales
    family Anarthriaceae
    family Centrolepidaceae
    family Cyperaceae
    family Ecdeiocoleaceae
    family Eriocaulaceae
    family Flagellariaceae
    family Hydatellaceae (now transferred out of the monocots; recently discovered to be an 'early-diverging' lineage of flowering plants.)
    family Joinvilleaceae
    family Juncaceae
    family Poaceae
    family Prioniaceae
    family Restionaceae
    family Sparganiaceae (now included in family Typhaceae)
    family Thurniaceae
    family Typhaceae
    family Xyridaceae

The morphology-based Cronquist system did not include an order named Poales, assigning these families to the orders Bromeliales, Cyperales, Hydatellales, Juncales, Restionales and Typhales.

In early systems, an order including the grass family did not go by the name Poales but by a descriptive botanical name such as Graminales in the Engler system (update of 1964) and in the Hutchinson system (first edition, first volume, 1926), Glumiflorae in the Wettstein system (last revised 1935) or Glumaceae in the Bentham & Hooker system (third volume, 1883).

Uses[edit]

The Poales are the most economically important order of monocots and possibly the most important order of plants in general. Within the order, by far the most important family economically is the family of grasses (Poaceae, syn. Gramineae), which includes barley, maize, millet, rice, and wheat. It is also the largest family in the order, far outnumbering the other families:

  • Poaceae: 12,070 species
  • Cyperaceae: 5,500 species
  • Bromeliaceae: 3,170 species
  • Eriocaulaceae: 1,150 species

References[edit]

  1. ^ a b c Angiosperm Phylogeny Group (2009). "An update of the Angiosperm Phylogeny Group classification for the orders and families of flowering plants: APG III" (PDF). Botanical Journal of the Linnean Society 161 (2): 105–121. doi:10.1111/j.1095-8339.2009.00996.x. Retrieved 2013-07-06. 
  • Bremer, K. (2002). Gondwanan Evolution of the Grass Alliance of Families (Poales). Evolution 56: 1374-1387. [Available online: Abstract ]
  • Judd, W. S., C. S. Campbell, E. A. Kellogg, P. F. Stevens, M. J. Donoghue (2002). Plant Systematics: A Phylogenetic Approach, 2nd edition. pp. 276–292 (Poales). Sinauer Associates, Sunderland, Massachusetts. ISBN 0-87893-403-0 .
  • Linder, H. Peter and Paula J. Rudall. 2005. Evolutionary History of the Poales. Annual Review of Ecology, Evolution, and Systematics 36: 107-124.
  • Small, J. K. (1903). Flora of the Southeastern United States, 48. New York, U.S.A.

External links[edit]