Poales
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| Missing image N_Pens_D9420.JPG Fountain grass on lava flow | ||||||||
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Anarthriaceae |
The Poales is a cosmopolitan order of monocotyledonous flowering plants. The order includes the very large family of grasses (Family Poaceae) and other allied families, and consists mostly of herbaceous plants, rarely shrubs or lianas. Flowers are typically small, enclosed by bracts, and arranged in an inflorescence (except in the genus, Mayaca, with solitary terminal flowers). The flowers are wind pollinated; seeds usually contain starch.
According to the most modern perceptions, Poales consists of eighteen families with about 850 genera and over 20,000 species. The largest families in the order are Poaceae (12,000 species), Cyperaceae (5,000 species), Bromeliaceae (1,400 species), and Eriocaulaceae (1,150 species). By far, the most economically important family is the Poaceae, which includes barley, maize, millet, rice, and wheat.
Today Poales are considered one of the more successful groups of plants on the planet. The ecological and economical importance of many species exceeds that of most other herbs. Estimates place the origin of the Poales in South America nearly 115 millions of years ago. The earliest known fossils include pollen and fruits that have been dated to the late Cretaceous (Bremer, 2000).
Classification
The Poales basically corresponds to the Order Restionales in Cronquist's (1981) classification, except that he placed the grasses in the Order Cyperales. Since then, it is generally agreed that the Poaceae belong here, however, and in fact a few authors have even removed the Restionaceae from the order. The Angiosperm Phylogeny Group's classification system includes several familes within the Order Poales that, in other classification schemes, constitute separate orders (i.e., Bromeliales, Cyperales, Hydatellales, and Juncales).
References
- Bremer, Kåre (2000). Gondwanan Evolution of the Grass Alliance of Families (Poales). Evolution 56, 1374-1387. (Available online: Abstract (http://www.bioone.org/bioone/?request=get-abstract&issn=0014-3820&volume=056&issue=07&page=1374) | Full text (HTML) (http://www.bioone.org/bioone/?request=get-document&issn=0014-3820&volume=056&issue=07&page=1374) | Full text (PDF) (http://www.bioone.org/pdfserv/i0014-3820-056-07-1374.pdf))
- W. S. Judd, 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 0878934030.
- J. K. Small (1903). Flora of the Southeastern United States, 48. New York, U. S. A.da:Græs-ordenen (Poales)
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