Poales

Last updated

Poales
Temporal range: Late Cretaceous - Recent (but see text) 66–0  Ma
Zboze.jpg
Common wheat (Triticum aestivum)
Scientific classification Red Pencil Icon.png
Kingdom: Plantae
Clade: Tracheophytes
Clade: Angiosperms
Clade: Monocots
Clade: Commelinids
Order: Poales
Small [1]
Families

See text

Diversity
About 1,050 genera[ citation needed ]

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.

Contents

Description

Billbergia pyramidalis of family Bromeliaceae Billbergia pyramidalis in Hyderabad Nursery W IMG 0425.jpg
Billbergia pyramidalis of family Bromeliaceae

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.

Taxonomy

The APG III system (2009) accepts the order within a monocot clade called commelinids, and accepts the following 16 families: [1]

The earlier APG system (1998) adopted the same placement of the order, although it used the spelling "commelinoids". It did not include the Bromeliaceae and Mayaceae, but had the additional families Prioniaceae (now included in Thurniaceae), Sparganiaceae (now in Typhaceae), and Hydatellaceae (now transferred out of the monocots; recently discovered to be an 'early-diverging' lineage of flowering plants).

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).

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. [2] 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. [3] The relationship between Centrolepidaceae and Restoniaceae within the restiid clade remains unclear; the first may actually be embedded in the latter. [3] [4]

Commelinales

Zingiberales

Poales
Bromeliad clade

Bromeliaceae

Typhaceae

Cyperid clade

Mayacaceae

Rapateaceae

Thurniaceae

Cyperaceae

Juncaceae

Xyrid clade

Eriocaulaceae

Xyridaceae

Graminid clade

Flagellariaceae

Poaceae

Ecdeiocoleaceae

Joinvilleaceae

Restiid clade

Anarthriaceae

Centrolepidaceae

Restionaceae

Diversity

The four most species-rich families in the order are:

Historic taxonomy

Cyperales

Cyperus javanicus Cyperus javanicus closeup.jpg
Cyperus javanicus

Cyperales was a name for an order of flowering plants. As used in the Engler system (update, of 1964) and in the Wettstein system it consisted of only the single family. In the Cronquist system it is used for an order (placed in subclass Commelinidae ) and circumscribed as (1981): [5]

The APG system now assigns the plants involved to the order Poales.

Eriocaulales

Eriocaulon decangulare Eriocaulon decangulare (1832).jpg
Eriocaulon decangulare

Eriocaulales is a botanical name for an order of flowering plants. The name was published by Takenoshin Nakai. In the Cronquist system the name was used for an order placed in the subclass Commelinidae . The order consisted of one family only (1981):

The APG IV system now assigns these plants to the order Poales.


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 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.

Related Research Articles

Restionales order of plants

Restionales is a botanical name for an order of flowering plants. In the Cronquist system it is used for an order and circumscribed as:

Juncales

Juncales is a botanical name for an order of flowering plants. In the Engler system and in the Cronquist system it is circumscribed as:

Hydatellales is a botanical name for an order of flowering plants. In the Cronquist system, 1981, the name was used for an order placed in the subclass Commelinidae in class Liliopsida [=monocotyledons]. The order consisted of one family only:

Monocotyledon Important clade of flowering plants

Monocotyledons, commonly referred to as monocots, are grass and grass-like flowering plants (angiosperms), the seeds of which typically contain only one embryonic leaf, or cotyledon. They constitute one of the major groups into which the flowering plants have traditionally been divided, the rest of the flowering plants having two cotyledons and therefore classified as dicotyledons, or dicots.

LiliopsidaBatsch is a botanical name for the class containing the family Liliaceae. It is considered synonymous with the name monocotyledon. Publication of the name is credited to Scopoli : see author citation (botany). This name is formed by replacing the termination -aceae in the name Liliaceae by the termination -opsida.

The Cronquist system is a taxonomic classification system of flowering plants. It was developed by Arthur Cronquist in a series of monographs and texts, including The Evolution and Classification of Flowering Plants and An Integrated System of Classification of Flowering Plants (1981).

Restionaceae

The Restionaceae, also called restiads and restios, are a family of flowering plants native to the Southern Hemisphere; they vary from a few centimeters to 3 meters in height. Following the APG IV (2016): the family now includes the former families Anarthriaceae, Centrolepidaceae and Lyginiaceae, and as such includes 51 genera with 572 known species. Based on evidence from fossil pollens, the Restionaceae likely originated more than 65 million years ago during the Late Cretaceous period, when the southern continents were still part of Gondwana.

Typhaceae

The Typhaceae are a family of flowering plants, sometimes called the cattail family. The botanical name for the family has been recognized by most taxonomists.

Xyridaceae

The Xyridaceae are a family of flowering plants. The botanical name has been recognized by many taxonomists and is known as the yellow-eyed grass family.

Sparganiaceae

Sparganiaceae is the botanical name for a family of flowering plants. Such a family was previously recognized by most taxonomists.

Thurniaceae

The Thurniaceae are a family of flowering plants composed of two genera with four species. The botanical name has been recognized by most taxonomists.

The APG system of plant classification is the first version of a modern, mostly molecular-based, system of plant taxonomy. Published in 1998 by the Angiosperm Phylogeny Group, it was replaced by the improved APG II in 2003, APG III system in 2009 and APG IV system in 2016.

Commelinids

In plant taxonomy, commelinids is an APG IV system named clade within the monocots within the angiosperms, distinguished by cell walls containing ferulic acid.

Rapateaceae

The Rapateaceae are a family of flowering plants. The botanical name has been recognized by most taxonomists.

The Kubitzki system is a system of plant taxonomy devised by Klaus Kubitzki, and is the product of an ongoing survey of vascular plants, entitled The Families and Genera of Vascular Plants, and extending to 15 volumes in 2018. The survey, in the form of an encyclopedia, is important as a comprehensive, multivolume treatment of the vascular plants, with keys to and descriptions of all families and genera, mostly by specialists in those groups. The Kubitzki system served as the basis for classification in Mabberley's Plant-Book, a dictionary of the vascular plants. Mabberley states, in his Introduction on page xi of the 2008 edition, that the Kubitzki system "has remained the standard to which other literature is compared".

A system of plant taxonomy, the Bessey system was published by Charles Bessey in 1915.

Anarthriaceae

The Anarthriaceae are a family of three genera, Anarthria, Hopkinsia and Lyginia of flowering plants, now included in Restionaceae following APG IV (2016). The family is accepted in the Angiosperm Phylogeny Group's classification system, APG III system, but is not considered a separate family in many other taxonomic systems. The three genera are herbaceous but differ greatly in characteristics.

Centrolepidaceae

Centrolepidaceae are a family of flowering plants now included in Restionaceae following APG IV (2016). The botanical name has been recognized by most taxonomists.

Joinvilleaceae

The Joinvilleaceae are a family of flowering plants with a single genus including four species. The APG II system, of 2003 assigns it to the order Poales in the clade commelinids in the monocots. The family consists of one genus with four currently accepted species, distributed from the Malay Peninsula to the Caroline Islands and high islands in the Pacific Ocean. It is evolutionarily significant as a relictual group closely related to grasses. They closely resemble large grass plants, in both general appearance and microanatomy, but possess fleshy fruits.

The APG III system of flowering plant classification is the third version of a modern, mostly molecular-based, system of plant taxonomy being developed by the Angiosperm Phylogeny Group (APG). Published in 2009, it was superseded in 2016 by a further revision, the APG IV system.

References

  1. 1 2 Angiosperm Phylogeny Group (2009). "An update of the Angiosperm Phylogeny Group classification for the orders and families of flowering plants: APG III". Botanical Journal of the Linnean Society. 161 (2): 105–121. doi: 10.1111/j.1095-8339.2009.00996.x . Archived from the original (PDF) on 2017-05-25. Retrieved 2013-07-06.
  2. Barrett, Craig F.; Baker, William J.; Comer, Jason R.; Conran, John G.; Lahmeyer, Sean C.; Leebens-Mack, James H.; Li, Jeff; Lim, Gwynne S.; Mayfield-Jones, Dustin R.; Perez, Leticia; Medina, Jesus; Pires, J. Chris; Santos, Cristian; Wm. Stevenson, Dennis; Zomlefer, Wendy B.; Davis, Jerrold I. (2015). "Plastid genomes reveal support for deep phylogenetic relationships and extensive rate variation among palms and other commelinid monocots". New Phytologist. 209 (2): 855–870. doi: 10.1111/nph.13617 . ISSN   0028-646X. PMID   26350789.
  3. 1 2 Bouchenak-Khelladi, Yanis; Muasya, A. Muthama; Linder, H. Peter (2014). "A revised evolutionary history of Poales: origins and diversification". Botanical Journal of the Linnean Society. 175 (1): 4–16. doi: 10.1111/boj.12160 . ISSN   0024-4074. Open Access logo PLoS transparent.svg
  4. Briggs, Barbara G.; Marchant, Adam D.; Perkins, Andrew J. (2014). "Phylogeny of the restiid clade (Poales) and implications for the classification of Anarthriaceae, Centrolepidaceae and Australian Restionaceae". Taxon. 63 (1): 24–46. doi:10.12705/631.1. ISSN   0040-0262.
  5. D.J. Mabberley. 2000. The Plant-Book, 2nd ed. Cambridge University Press, Cambridge, UK, 858 p. [H. Pfefferkorn/H. Pfefferkorn/H. Pfefferkorn]

Bibliography