Pandanales, the pandans or screw-pines, is an

order Order, ORDER or Orders may refer to: * A socio-political or established or existing order, e.g. World order, Ancien Regime, Pax Britannica * Categorization, the process in which ideas and objects are recognized, differentiated, and understood ...

flowering plant Flowering plants are plants that bear flowers and fruits, and form the clade Angiospermae (). The term angiosperm is derived from the Ancient Greek, Greek words (; 'container, vessel') and (; 'seed'), meaning that the seeds are enclosed with ...

s placed in the

monocot Monocotyledons (), commonly referred to as monocots, (Lilianae ''sensu'' Chase & Reveal) are flowering plants whose seeds contain only one Embryo#Plant embryos, embryonic leaf, or cotyledon. A monocot taxon has been in use for several decades, but ...

clade In biology, a clade (), also known as a Monophyly, monophyletic group or natural group, is a group of organisms that is composed of a common ancestor and all of its descendants. Clades are the fundamental unit of cladistics, a modern approach t ...

in the

Angiosperm Phylogeny Group The Angiosperm Phylogeny Group (APG) is an informal international group of systematic botanists who collaborate to establish a consensus on the taxonomy of flowering plants (angiosperms) that reflects new knowledge about plant relationships disc ...

and Angiosperm Phylogeny Web

systems A system is a group of interacting or interrelated elements that act according to a set of rules to form a unified whole. A system, surrounded and influenced by its environment, is described by its boundaries, structure and purpose and is exp ...

. Within the monocots Pandanales are grouped in the

lilioid monocots Lilioid monocots (lilioids, liliid monocots, petaloid monocots, petaloid lilioid monocots) is an informal name used for a grade (biology), grade (grouping of taxa with common characteristics) of five monocot order (biology), orders (Petrosavial ...

where they are in a

sister group In phylogenetics, a sister group or sister taxon, also called an adelphotaxon, comprises the closest relative(s) of another given unit in an evolutionary tree. Definition The expression is most easily illustrated by a cladogram: Taxon A and ...

relationship with the Dioscoreales. Historically the order has consisted of a number of different

families Family (from ) is a group of people related either by consanguinity (by recognized birth) or affinity (by marriage or other relationship). It forms the basis for social order. Ideally, families offer predictability, structure, and safety as ...

in different systems but modern classification of the order is based primarily on

molecular phylogenetics Molecular phylogenetics () is the branch of phylogeny that analyzes genetic, hereditary molecular differences, predominantly in DNA sequences, to gain information on an organism's evolutionary relationships. From these analyses, it is possible to ...

despite diverse

morphology Morphology, from the Greek and meaning "study of shape", may refer to: Disciplines *Morphology (archaeology), study of the shapes or forms of artifacts *Morphology (astronomy), study of the shape of astronomical objects such as nebulae, galaxies, ...

which previously placed many of the families in other groupings based on apparent similarity. Members of the order have a subtropical distribution and includes

trees In botany, a tree is a perennial plant with an elongated stem, or trunk, usually supporting branches and leaves. In some usages, the definition of a tree may be narrower, e.g., including only woody plants with secondary growth, only p ...

shrubs A shrub or bush is a small to medium-sized perennial woody plant. Unlike herbaceous plants, shrubs have persistent woody stems above the ground. Shrubs can be either deciduous or evergreen. They are distinguished from trees by their multiple ...

, and vines as well as

herbaceous Herbaceous plants are vascular plants that have no persistent woody stems above ground. This broad category of plants includes many perennials, and nearly all annuals and biennials. Definitions of "herb" and "herbaceous" The fourth edition of ...

plants. The order consists of 5 families, 36 genera and about 1,610

species A species () is often defined as the largest group of organisms in which any two individuals of the appropriate sexes or mating types can produce fertile offspring, typically by sexual reproduction. It is the basic unit of Taxonomy (biology), ...

Description

Pandanales are highly diverse including large arboraceous plants of tropical rainforests and coastal areas, climbing vines and lianas, as well as very small achlorophyllous (mycoheterotrophic) and

saprophytic Saprotrophic nutrition or lysotrophic nutrition is a process of chemoheterotrophic extracellular digestion involved in the processing of decayed (dead or waste) organic matter. It occurs in saprotrophs, and is most often associated with fungi ...

forest floor The forest floor, also called detritus or wikt:duff#Noun 2, duff, is the part of a forest ecosystem that mediates between the living, aboveground portion of the forest and the mineral soil, principally composed of dead and decaying plant matter ...

species. This has made it difficult to reliably define

synapomorphies In phylogenetics, an apomorphy (or derived trait) is a novel character or character state that has evolved from its ancestral form (or plesiomorphy). A synapomorphy is an apomorphy shared by two or more taxa and is therefore hypothesized to ...

, but the loss of trimery distinguishes many of them from other lilioid monocots. The Pandanales order is distinctive with its highly variable and hardly definable floral morphology, especially the number of

stamens The stamen (: stamina or stamens) is a part consisting of the male reproductive organs of a flower. Collectively, the stamens form the androecium., p. 10 Morphology and terminology A stamen typically consists of a stalk called the filamen ...

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 of

monocots Monocotyledons (), commonly referred to as monocots, ( Lilianae '' sensu'' Chase & Reveal) are flowering plants whose seeds contain only one embryonic leaf, or cotyledon. A monocot taxon has been in use for several decades, but with various ranks a ...

. A good example is the female reproductive organ and its position relative to other parts of the

flower Flowers, also known as blooms and blossoms, are the reproductive structures of flowering plants ( angiosperms). Typically, they are structured in four circular levels, called whorls, around the end of a stalk. These whorls include: calyx, m ...

. Some of the species included in the families

Pandanaceae Pandanaceae is a family of flowering plants native to the tropics and subtropics of the Old World, from West Africa to the Pacific. It contains 982 known species in five genera, of which the type genus, ''Pandanus'', is the most important, with s ...

and Stemonaceae show flowers formed from only one

carpel Gynoecium (; ; : gynoecia) is most commonly used as a collective term for the parts of a flower that produce ovules and ultimately develop into the fruit and seeds. The gynoecium is the innermost whorl of a flower; it consists of (one or more ...

, while in the Triuridaceae, a family that lacks

chlorophyll Chlorophyll is any of several related green pigments found in cyanobacteria and in the chloroplasts of algae and plants. Its name is derived from the Greek words (, "pale green") and (, "leaf"). Chlorophyll allows plants to absorb energy ...

, the carpels are free from each other. In fact, the Triuridaceae possess the least "typical" flower morphology in the order.

Taxonomy

History

The components of the order ''sensu'' APG have been difficult to place consistently, and historically have been associated with a number of other groupings. The Bentham & Hooker system (1883) had a similar order under the name Nudifloreae, incorporating: * Pandaneae * Cyclanthaceae * Typhaceae *

Aroideae Aroideae is a subfamily of flowering plants in the family (biology), family Araceae. It is the largest subfamily in Araceae and consists of about 72 genera, and 2,300 species. Many Aroideae have spiny pollen grains without a sporopollenin outer e ...

Lemnaceae Lemnoideae is a subfamily of flowering aquatic plants, known as duckweeds, water lentils, or water lenses. They float on or just beneath the surface of still or slow-moving bodies of fresh water and wetlands. Also known as bayroot, they arose fr ...

The

Wettstein system A list of systems of plant taxonomy, system of plant taxonomy, the Wettstein system recognised the following main groups, according to Richard Wettstein's ''Handbuch der Systematischen Botanik'' (1901–1924). 3rd edition (1924) Outline Syn ...

(1935) placed the order in class Monocotyledones and used a different circumscription, incorporating: *

* Sparganiaceae * Typhaceae The

Cronquist system The Cronquist system is a list of systems of plant taxonomy, taxonomic classification system of angiosperms, flowering plants. It was developed by Arthur Cronquist in a series of monographs and texts, including ''The Evolution and Classification of ...

(1981) placed the order in subclass

Arecidae Arecidae is a botanical name at the rank of subclass. Circumscription of the subclass will vary with the taxonomic system being used (there are many such systems); the only requirement being that it includes the family Arecaceae. Arecidae in ...

in class Liliopsida monocotyledonswith only one family: *

In the classification system of Dahlgren the Pandanales were in the

superorder Order () is one of the eight major hierarchical taxonomic ranks in Linnaean taxonomy. It is classified between family and class. In biological classification, the order is a taxonomic rank used in the classification of organisms and recognized ...

Pandaniflorae (also called Pandananae) with the single family Pandanaceae.

Angiosperm Phylogeny Group

The

APG III system 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 f ...

(2009) places the Pandanales in the

. Both the APG III and APG II systems include five families in this order. 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 the Velloziaceae, but similarities with the family

Zingiberaceae Zingiberaceae () or the ginger family is a family of flowering plants made up of about 50 genera with a total of about 1600 known species of aromatic perennial herbs with creeping horizontal or tuberous rhizomes distributed throughout tropical ...

(which is a part of a whole different order –

Zingiberales The Zingiberales are flowering plants forming one of four orders in the commelinids clade of monocots, together with its sister order, Commelinales. The order includes 68 genera and 2,600 species. Zingiberales are a unique though morpholog ...

) do not exclude the chance for a different phylogeny. The family Velloziaceae on its own is placed at the base of the tree. The

and Cyclanthaceae are sister groups, and they form a clade which on its own is sister to the Stemonaceae (a family composed of two more clades).

Evolution

The order Dioscoreales holds sister relationship with Pandanales by diverging from them around 121 million years ago in the mid-

Cretaceous The Cretaceous ( ) is a geological period that lasted from about 143.1 to 66 mya (unit), million years ago (Mya). It is the third and final period of the Mesozoic Era (geology), Era, as well as the longest. At around 77.1 million years, it is the ...

. The formation of the

crown group In phylogenetics, the crown group or crown assemblage is a collection of species composed of the living representatives of the collection, the most recent common ancestor of the collection, and all descendants of the most recent common ancestor ...

s took place with a difference of 2 million years between the orders - 116 Mya for the Dioscoreales and 114 Mya for the Pandanales. However, the stem group of the Pandanales is much older and goes back to 130 Mya in the early

.Merckx. Diversification of myco-heterotrophic angiosperms: Evidence from Burmanniaceae. BMC Evolutionary Biology 2008
/ref>

Phylogeny

Subdivision

The composition of the order in APG III and APG II were slightly from that in the 1998

APG system The APG system (Angiosperm Phylogeny Group 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 ...

, which used the circumscription * Cyclanthaceae *

* Stemonaceae * Velloziaceae APG III includes the following families; * Cyclanthaceae *

* Stemonaceae * Triuridaceae * Velloziaceae

Distribution

The order contains members mainly distributed in all the

tropical The tropics are the regions of Earth surrounding the equator, where the sun may shine directly overhead. This contrasts with the temperate or polar regions of Earth, where the Sun can never be directly overhead. This is because of Earth's ax ...

and

subtropical The subtropical zones or subtropics are geographical zone, geographical and Köppen climate classification, climate zones immediately to the Northern Hemisphere, north and Southern Hemisphere, south of the tropics. Geographically part of the Ge ...

regions of the world, both New and Old World (including

Africa Africa is the world's second-largest and second-most populous continent after Asia. At about 30.3 million km2 (11.7 million square miles) including adjacent islands, it covers 20% of Earth's land area and 6% of its total surfac ...

South America South America is a continent entirely in the Western Hemisphere and mostly in the Southern Hemisphere, with a considerably smaller portion in the Northern Hemisphere. It can also be described as the southern Subregion#Americas, subregion o ...

Australia Australia, officially the Commonwealth of Australia, is a country comprising mainland Australia, the mainland of the Australia (continent), Australian continent, the island of Tasmania and list of islands of Australia, numerous smaller isl ...

and

Asia Asia ( , ) is the largest continent in the world by both land area and population. It covers an area of more than 44 million square kilometres, about 30% of Earth's total land area and 8% of Earth's total surface area. The continent, which ...

). Also, a species is present in

China China, officially the People's Republic of China (PRC), is a country in East Asia. With population of China, a population exceeding 1.4 billion, it is the list of countries by population (United Nations), second-most populous country after ...

Ecology

The species are members of various ecological groups, including tropical shrubs, lianas and trees,

xerophytic A xerophyte () is a species of plant that has adaptations to survive in an environment with little liquid water. Examples of xerophytes include cactus, cacti, pineapple and some gymnosperm plants. The morphology (biology), morphology and physiology ...

plants, mycoheterotrophs, as well as different

representatives.

Uses

Several species in this order produce strap-like

leaves A leaf (: leaves) is a principal appendage of the stem of a vascular plant, usually borne laterally above ground and specialized for photosynthesis. Leaves are collectively called foliage, as in "autumn foliage", while the leaves, stem, ...

used for basketry and mats; ''

Pandanus ''Pandanus'' is a genus of monocots with about 578 accepted species. They are palm-like, dioecious trees and shrubs native to the Old World tropics and subtropics. Common names include pandan, screw palm and screw pine. The genus is classified ...

'' (Pandanaceae) is used across

Oceania Oceania ( , ) is a region, geographical region including Australasia, Melanesia, Micronesia, and Polynesia. Outside of the English-speaking world, Oceania is generally considered a continent, while Mainland Australia is regarded as its co ...

for thatch, basketry, and to make cloth, and '' Carludovica palmata'' (Cyclanthaceae) leaves are made into Panama hats. Other members as '' Stemona'' are present in

traditional Chinese medicine Traditional Chinese medicine (TCM) is an alternative medicine, alternative medical practice drawn from traditional medicine in China. A large share of its claims are pseudoscientific, with the majority of treatments having no robust evidence ...

and possess medical properties. Some species are used as

insecticide Insecticides are pesticides used to kill insects. They include ovicides and larvicides used against insect eggs and larvae, respectively. The major use of insecticides is in agriculture, but they are also used in home and garden settings, i ...

s. Some species of ''Pandanus'' are used as ornamentals. '' Pandanus amaryllifolius'' is a common food

flavoring A flavoring (or flavouring), also known as flavor (or flavour) or flavorant, is a food additive that is used to improve the taste or smell of food. It changes the perceptual impression of food as determined primarily by the chemoreceptors of ...

Southeast Asia Southeast Asia is the geographical United Nations geoscheme for Asia#South-eastern Asia, southeastern region of Asia, consisting of the regions that are situated south of China, east of the Indian subcontinent, and northwest of the Mainland Au ...

and

karuka The karuka (''Pandanus julianettii'', also called karuka nut and ''Pandanus'' nut) is a species of tree in the screwpine family (Pandanaceae) and an important regional food crop in New Guinea. The nuts are more nutritious than coconuts, and ar ...

(''Pandanus julianettii'') is a

staple food A staple food, food staple, or simply staple, is a food that is eaten often and in such quantities that it constitutes a dominant portion of a standard diet for an individual or a population group, supplying a large fraction of energy needs an ...

New Guinea New Guinea (; Hiri Motu: ''Niu Gini''; , fossilized , also known as Papua or historically ) is the List of islands by area, world's second-largest island, with an area of . Located in Melanesia in the southwestern Pacific Ocean, the island is ...

References

Bibliography

* *

External links

Merckx V. Cretaceous Origins of Myco-Heterotrophic Lineages in Dioscoreales. 2010

* ttp://www.mobot.org/MOBOT/Research/APweb/orders/pandanalesweb.htm#Pandanales Angiosperm Phylogeny Web: Pandanales
Berry, PE. Pandanales. Encyclopædia Britannica 2016
* * {{Authority control Angiosperm orders Extant Aptian first appearances