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| Pandanales | |
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| Carludovica palmata | |
Scientific classification | |
| Kingdom: | Plantae |
| Clade: | Tracheophytes |
| Clade: | Angiosperms |
| Clade: | Monocots |
| Order: | Pandanales R.Br.exBercht. &J.Presl[1] |
| Type species | |
| Pandanus tectorius Parkinson | |
| Families | |
Pandanales, thepandans orscrew-pines, is anorder offlowering plants placed in themonocotclade in theAngiosperm Phylogeny Group andAngiosperm Phylogeny Websystems. Within the monocots Pandanales are grouped in thelilioid monocots where they are in asister group relationship with theDioscoreales. Historically the order has consisted of a number of differentfamilies in different systems but modern classification of the order is based primarily onmolecular phylogenetics despite diversemorphology which previously placed many of the families in other groupings based on apparent similarity. Members of the order have a subtropical distribution and includestrees,shrubs, andvines as well asherbaceous plants. The order consists of 5 families, 36 genera and about 1,610species.
Pandanales are highly diverse including largearboraceous plants oftropical rainforests andcoastal areas, climbingvines andlianas, as well as very smallachlorophyllous (mycoheterotrophic) andsaprophyticherbaceousforest floor species. This has made it difficult to reliably definesynapomorphies, but the loss oftrimery distinguishes many of them from other lilioid monocots.[2]
The Pandanales order is distinctive with its highly variable and hardly definable floral morphology,[2] especially the number ofstamens and their structure as well as many other characteristics. In some of the members, different interpretations exist regarding the composition and organization of the reproductive structures.
The order includes plants with traits that seem atypical when compared to other groups ofmonocots. A good example is the female reproductive organ and its position relative to other parts of theflower. Some of the species included in the familiesPandanaceae andStemonaceae show flowers formed from only onecarpel, while in theTriuridaceae, a family that lackschlorophyll, the carpels are free from each other. In fact, the Triuridaceae possess the least "typical" flower morphology in the order.[citation needed]
The components of the ordersensu APG have been difficult to place consistently, and historically have been associated with a number of other groupings.[2] TheBentham & Hooker system (1883) had a similar order under the name Nudifloreae, incorporating:
TheWettstein system (1935) placed the order in class Monocotyledones and used a different circumscription, incorporating:
TheCronquist system (1981) placed the order in subclassArecidae in classLiliopsida [=monocotyledons] with only one family:
In the classification system ofDahlgren the Pandanales were in thesuperorder Pandaniflorae (also called Pandananae) with the single family Pandanaceae.
TheAPG III system (2009) places the Pandanales in themonocots. Both the APG III andAPG II systems include five families in this order.[1]Since the morphology of the order varies on such scale, its classification and phylogeny are based on genetic analyses.
Inside the order, some doubt remains about the position of the entirely mycoheterotrophic family Triuridaceae, since it is the only one on which genetic analyses have not yet been applied. With high probability, the family may be sister to theVelloziaceae, but similarities with the familyZingiberaceae (which is a part of a whole different order –Zingiberales) do not exclude the chance for a different phylogeny. The family Velloziaceae on its own is placed at the base of the tree. ThePandanaceae andCyclanthaceae are sister groups, and they form a clade which on its own is sister to theStemonaceae (a family composed of two more clades).
The orderDioscoreales holds sister relationship with Pandanales by diverging from them around 121 million years ago in the mid-Cretaceous. The formation of thecrown groups took place with a difference of 2 million years between the orders - 116 Mya for the Dioscoreales and 114 Mya for the Pandanales.However, thestem group of the Pandanales is much older and goes back to 130 Mya in the earlyCretaceous.[3]
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The composition of the order in APG III and APG II were slightly from that in the 1998APG system, which used the circumscription[1]
APG III includes the following families;
The order contains members mainly distributed in all thetropical andsubtropical regions of the world, both New and Old World (includingAfrica,South America,Australia andAsia).[2] Also, a species is present inChina.
The species are members of various ecological groups, including tropical shrubs, lianas and trees,xerophytic plants,mycoheterotrophs, as well as differentherbaceous representatives.
Several species in this order produce strap-likeleaves used for basketry and mats;Pandanus (Pandanaceae) is used acrossOceania for thatch, basketry, and to make cloth, andCarludovica palmata (Cyclanthaceae) leaves are made intoPanama hats. Other members asStemona are present intraditional Chinese medicine and possess medical properties. Some species are used asinsecticides. Some species ofPandanus are used as ornamentals.Pandanus amaryllifolius is a common foodflavoring inSoutheast Asia andkaruka (Pandanus julianettii) is astaple food inNew Guinea.
Data related toPandanales at Wikispecies
Media related toPandanales at Wikimedia CommonsOrders offlowering plants (APG IV) | ||||||||||||||||||||||||||||||||||||||||||||||||||
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