Poales

Poales Temporal range: Late Cretaceous - Recent (but see text) 66–0Ma PreЄ Є O S D C P T J K Pg N
Common wheat (Triticum aestivum)
Scientific classification
Kingdom:	Plantae
(unranked):	Angiosperms
(unranked):	Monocots
(unranked):	Commelinids
Order:	Poales Small
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 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. It uses this circumscription:

• order Poales

  family Anarthriaceae

  family Bromeliaceae

  family Centrolepidaceae

  family Cyperaceae

  family Ecdeiocoleaceae

  family Eriocaulaceae

  family Flagellariaceae

  family Joinvilleaceae

  family Juncaceae

  family Mayacaceae

  family Poaceae

  family Rapateaceae

  family Restionaceae

  family Thurniaceae

  family Typhaceae

  family Xyridaceae

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.

Setaria verticillata from family Poaceae

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).

Billbergia pyramidalis of family Bromeliaceae

[edit] Uses

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

[edit] References

Wikimedia Commons has media related to: Poales

Wikispecies has information related to: Poales

• 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.

[edit] External links

• NCBI Taxonomy Browser
• APWeb