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Xyridaceae The Poales is a cosmopolitan order of monocotyledonous flowering plants. The order includes Family Poaceae (grasses) and allied families. By far, the most economically important family is the Poaceae — the grass or corn family, which includes barley, maize, millet, rice, and wheat.
The order consists mostly of herbs and herbaceous plants, rarely shrubs or lianas. Flowers have bracts and are usually small, arranged into inflorescences of various forms (except for genus Mayaca , which has solitary terminal flowers). Seeds usually contain starch.
One of most prominent features of many families inside Poales is the wind pollination, to which they are perfectly fit.
According to the modern perception, Poales consist of eighteen families with about 850 genera and over 20000 species. The most important families in the order are Poaceae (12000 species), Cyperaceae (5000 sp.), Bromeliaceae (1400 sp.) and Eriocaulaceae (1150 sp.)
Today Poales are one of the most successful groups of plants, and its ecological and economical importance far exceeds that of any other herbs. Modern estimates (Bremer, 2000) place its origin in the South America, nearly 115 millions of years ago (in the middle Cretaceous). The earliest known fossils include pollen and fruits and are dated to the late Cretaceous.
This group basically corresponds to the Order Restionales in Cronquist's (1981) classification, except that he placed the grasses in the Order Cyperales. Since then it has generally been agreed that the Poaceae belong here, however, and in fact a few authors have removed the Restionaceae instead.
The Angiosperm Phylogeny Group's classification system includes several familes in order Poales that, in other classification systems, constitute separate orders (i.e. Bromeliales, Cyperales, Hydatellales, and Juncales).
- Bremer, Kåre (2000). Gondwanan Evolution of the Grass Alliance of Families (Poales). Evolution 56, 1374-1387. (Available online: Abstract | Full text (HTML) | Full text (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.
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