|Common wheat (Triticum aestivum)|
|About 1,050 genera|
The Poales are a large
The flowers are typically small, enclosed by bracts, and arranged in inflorescences (except in three species of the genus Mayaca, which possess very reduced, one-flowered inflorescences). The flowers of many species are wind pollinated; the seeds usually contain starch.
- Restionaceae (including Centrolepidaceae)
Evolution and phylogeny
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 phylogenetic position of Poales within the commelinids was difficult to resolve, but an analysis using complete chloroplast DNA found support for Poales as sister group of Commelinales plus Zingiberales. Major lineages within the Poales have been referred to as bromeliad, cyperid, xyrid, graminid, and restiid clades. A phylogenetic analysis resolved most relationships within the order but found weak support for the monophyly of the cyperid clade. The relationship between Centrolepidaceae and Restoniaceae within the restiid clade remains unclear; the first may actually be embedded in the latter.
The four most species-rich families in the order are:
- Poaceae: 12,070 species
- Cyperaceae: 5,500 species
- Bromeliaceae: 3,170 species
- Eriocaulaceae: 1,150 species
Typha latifolia, Typhaceae
Carex demissa, Cyperaceae
Xyris complanata, Xyridaceae
Elegia capensis, Restionaceae
Foxtail millet, Poaceae
Cyperales was a name for an order of
- order Cyperales
- family Cyperaceae
- family Poaceae (or Gramineae)
The APG system now assigns the plants involved to the order Poales.
Eriocaulales is a
- order Eriocaulales
- family Eriocaulaceae
The APG IV system now assigns these plants to the order Poales.
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 the starch staples barley, maize, millet, rice, and wheat as well as bamboos (mostly used structurally, like wood, but somewhat as vegetables), and a few "seasonings" like sugarcane and lemongrass. Graminoids, especially the grasses, are typically dominant in open (low moisture but not yet arid, or also fire climax) habitats like prairie/steppe and savannah and thus form a large proportion of the forage of grazing livestock. Possibly due to pastoral nostalgia or simply a desire for open areas for play, they dominate most Western yards as lawns, which consume vast sums of money in upkeep (artificial grazing—mowing—for aesthetics and to keep the allergenic flowers suppressed, irrigation, and fertilizer). Many Bromeliaceae are used as ornamental plants (and one, the pineapple, is internationally grown in the tropics for fruit). Many wetland species of sedges, rushes, grasses, and cattails are important habitat plants for waterfowl, are used in weaving chair seats, and (especially cattails) were important pre-agricultural food sources for man. Two sedges, chufa (Cyperus esculentus, also a significant weed) and water chestnut (Eleocharis dulcis) are still at least locally important wetland starchy root crops.
- Bremer, K (2002). "Gondwanan Evolution of the Grass Alliance of Families (Poales)". Evolution. 56 (7): 1374–1387. PMID 12206239.
- 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; Rudall, Paula J. (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, United States