Magnoliids

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Magnoliids
Asimina triloba - pawpaw - desc-flower.jpg
Flower of Asimina triloba
Scientific classification Red Pencil Icon.png
Kingdom: Plantae
Clade: Tracheophytes
Clade: Angiosperms
Clade: Magnoliids
Type species
Magnolia virginiana
Orders

Canellales
Laurales
Magnoliales
Piperales

Magnoliids (or Magnoliidae or Magnolianae) are a group of flowering plants. Until recently, the group included about 9,000 [1] species, including magnolias, nutmeg, bay laurel, cinnamon, avocado, black pepper, tulip tree and many others. The group is characterized by trimerous flowers, pollen with one pore, and usually branching-veined leaves.

Contents

Some members of the subclass are among the earliest angiosperms and share anatomical similarities with gymnosperms like stamens that resemble the male cone scales of conifers and carpels found on the long flowering axis. [2]

Classification

"Magnoliidae" is the botanical name of a subclass, and "magnoliids" is an informal name that does not conform to the International Code of Nomenclature for algae, fungi, and plants. The circumscription of a subclass will vary with the taxonomic system being used. The only requirement is that it must include the family Magnoliaceae. [3] The informal name "magnoliids" is used by some researchers to avoid the confusion that recently surrounds the name "Magnoliidae." More recently,[ clarification needed ] the group[ clarification needed ] has been redefined under the PhyloCode as a node-based clade comprising the Canellales, Laurales, Magnoliales, and Piperales.[ citation needed ] Chase & Reveal have proposed "Magnoliidae" as the name used for the entire group of flowering plants, and the formal name "Magnolianae" for the group of four orders discussed here. [4]

APG system

The APG III (2009) and its predecessor systems did not originally use formal botanical names above the rank of order. Under those systems, larger clades were usually referred to by informal names, such as "magnoliids" (plural, not capitalized) or "magnoliid complex". The formal name in Linnean nomenclature was specified in a separate APG publication as the existing name "Magnolianae" Takht. (1967). [4] The APG III recognizes a clade within the angiosperms for the magnoliids. The circumscription is:

clade magnoliids
order Canellales
order Laurales
order Magnoliales
order Piperales

Chloranthales

magnoliids

Canellales

Piperales

Laurales

Magnoliales

monocots

Ceratophyllales

eudicots

The current phylogeny and composition of the magnoliids. [5] [6]

The clade includes most of the basal groups of the angiosperms. This clade was formally named Magnoliidae in 2007 under provisions of the PhyloCode . [7]

Cronquist system

Flower of Magnolia obovata, showing multiple petals, stamens, and pistils. Magnolia obovata 02.jpg
Flower of Magnolia obovata , showing multiple petals, stamens, and pistils.

The Cronquist system (1981) used the name Magnoliidae for one of six subclasses (within class Magnoliopsida = dicotyledons). In the original version of this system the circumscription was: [8]

Dahlgren and Thorne systems

Both Dahlgren and Thorne classified the magnoliids (sensu APG) in superorder Magnolianae, rather than as a subclass. [9] In their systems, the name Magnoliidae is used for a much larger group including all dicotyledons. This is also the case in some of the systems derived from the Cronquist system.

Dahlgren divided his Magnolianae into ten orders, more than other systems of the time, and unlike Cronquist and Thorne, he did not include the Piperales. [10] Thorne grouped most of his Magnolianae into two large orders, Magnoliales and Berberidales, although his Magnoliales was divided into suborders along lines similar to the ordinal groupings used by both Cronquist and Dahlgren. Thorne revised his system in 2000, restricting the name Magnoliidae to include only the Magnolianae, Nymphaeanae, and Rafflesianae, and removing the Berberidales and other previously included groups to his subclass Ranunculidae. [11] This revised system diverges from the Cronquist system, but agrees more closely with the circumscription later published under APG II.

Comparison table

Comparison of classification systems is often difficult. Two authors may apply the same name to groups with different composition of members; for example, Dahlgren's Magnoliidae includes all dicots, whereas Cronquists' Magnoliidae is only one of five dicot groups. Two authors may also describe the same group with nearly identical composition, but each may then apply a different name to that group or place the group at a different taxonomic rank. For example, the composition of Cronquist's subclass Magnoliidae is nearly the same as Thorne's (1992) superorder Magnolianae, despite the difference in taxonomic rank.

Because of these difficulties and others, the synoptic table below imprecisely compares the definition of "magnoliid" groups in the systems of four authors. For each system, only orders are named in the table. All orders included by a particular author are listed and linked in that column. When a taxon is not included by that author, but was included by an author in another column, that item appears in unlinked italics and indicates remote placement. The sequence of each system has been altered from its publication in order to pair corresponding taxa between columns.

Comparison of the magnoliids across five systems
APG II system [12]
magnoliids
Cronquist system [8]
Magnoliidae
Dahlgren system [10]
Magnolianae
Thorne system (1992) [9]
Magnolianae
Thorne system (2000) [11]
Magnolianae
Laurales Laurales Laurales Magnoliales Magnoliales
Magnoliales Magnoliales Magnoliales
Annonales
Canellales Winterales
Piperales Lactoridales
Aristolochiales Aristolochiales
Piperales Piperales in Nymphaeanae
unplaced or in basal clades Chloranthales
Illiciales Illiciales
in Rosidae Rafflesiales in Rafflesianaein Rafflesianae
Nymphaeales in Nymphaeanaein Nymphaeanaein Nymphaeanae
Ceratophyllales in Ranunculidae
placed in eudicot clade Nelumbonales Nelumbonales
Ranunculales in Ranunculanae Berberidales
Papaverales
in Dilleniidaein Theanae Paeoniales

Economic uses

The magnoliids is a large group of plants, with many species that are economically important as food, drugs, perfumes, timber, and as ornamentals, among many other uses.

The avocado has been cultivated in the Americas for thousands of years. Persea americana 2.jpg
The avocado has been cultivated in the Americas for thousands of years.

One widely cultivated magnoliid fruit is the avocado (Persea americana), which is believed to have been cultivated in Mexico and Central America for nearly 10,000 years. [13] Now grown throughout the tropics, it probably originates from the Chiapas region of Mexico or Guatemala, where "wild" avocados may still be found. [14] The soft pulp of the fruit is eaten fresh or mashed into guacamole. The ancient peoples of Central America were also the first to cultivate several fruit-bearing species of Annona . [8] These include the custard-apple (A. reticulata), soursop (A. muricata), sweetsop or sugar-apple (A. squamosa), and the cherimoya (A. cherimola). Both soursop and sweetsop now are widely grown for their fruits in the Old World as well. [15]

Some members of the magnoliids have served as important food additives, such as black pepper, bay laurel and cinnamon. Oil of sassafras was formerly used as a key flavoring in both root beer and in sarsaparilla. [16] The primary ingredient responsible for the oil's flavor is safrole, but it is no longer used in either the United States or Canada. Both nations banned the use of safrole as a food additive in 1960 as a result of studies that demonstrated safrole promoted liver damage and tumors in mice. [17] Consumption of more than a minute quantity of the oil causes nausea, vomiting, hallucinations, and shallow rapid breathing. It is very toxic, and can severely damage the kidneys. [18] In addition to its former use as a food additive, safrole from either Sassafras or Ocotea cymbarum is also the primary precursor for synthesis of MDMA (methylenedioxymethamphetamine), commonly known as the drug ecstasy. [19]

Nutmeg fruits are a source of the hallucinogen myristicin. Myris fragr Fr 080112-3294 ltn.jpg
Nutmeg fruits are a source of the hallucinogen myristicin.

Other magnoliids also are known for their narcotic, hallucinogenic, or paralytic properties. The Polynesian beverage kava is prepared from the pulverized roots of Piper methysticum, and has both sedative and narcotic properties. [15] It is used throughout the Pacific in social gatherings or after work to relax. Likewise, some native peoples of the Amazon take a hallucinogenic snuff made from the dried and powdered fluid exuded from the bark of Virola trees. [8] Another hallucinogenic compound, myristicin, comes from the spice nutmeg. [20] As with safrole, ingestion of nutmeg in quantities can lead to hallucinations, nausea, and vomiting, with symptoms lasting several days. [21] A more severe reaction comes from poisoning by rodiasine and demethylrodiasine, the active ingredients in fruit extract from Chlorocardium venenosum . These chemicals paralyze muscles and nerves, resulting in tetanus-like reactions in animals. The Cofán peoples of westernmost Amazon in Colombia and Ecuador use the compound as a poison to tip their arrows in hunting. [22]

Not all the effects of chemical compounds in the magnoliids are detrimental. In previous centuries, sailors would use Winter's Bark from the South American tree Drimys winteri to ward off the vitamin-deficiency of scurvy. [15] Today, benzoyl is extracted from Lindera benzoin (common spicebush) for use as a food additive and skin medicine, due to its anti-bacterial and anti-fungal properties. [23] Drugs extracted from the bark of Magnolia have long been used in traditional Chinese medicine. Scientific investigation of magnolol and honokiol have shown promise for their use in dental health. Both compounds demonstrate effective anti-bacterial activity against the bacteria responsible for bad breath and dental caries. [24] [25] Several members of the family Annonaceae are also under investigation for uses of a group of chemicals called acetogenins. The first acetogenin discovered was uvaricin, which has anti-leukemic properties when used in living organisms. Other acetogenins have been discovered with anti-malarial and anti-tumor properties, and some even inhibit HIV replication in laboratory studies. [26]

Many magnoliid species produce essential oils in their leaves, bark, or wood. The tree Virola surinamensis (Brazilian "nutmeg") contains trimyristin, which is extracted in the form of a fat and used in soaps and candles, as well as in shortenings. [27] Other fragrant volatile oils are extracted from Aniba rosaeodora (bois-de-rose oil), Cinnamomum porrectum , Cinnamomum cassia , and Litsea odorifera for scenting soaps. [28] Perfumes also are made from some of these oils; ylang-ylang comes from the flowers of Cananga odorata , and is used by Arab and Swahili women. [15] A compound called nutmeg butter is produced from the same tree as the spice of that name, but the sweet-smelling "butter" is used in perfumery or as a lubricant rather than as a food.

Magnoliids are also important sources of spices and herbs used to flavor food, including the spices black pepper, cinnamon and nutmeg, and the herb bay laurel.

See also

Related Research Articles

Arecales Order of flowering plants

Arecales is an order of flowering plants. The order has been widely recognised only for the past few decades; until then, the accepted name for the order including these plants was Principes.

Fabales Order of flowering plants in the dicots

The Fabales are an order of flowering plants included in the rosid group of the eudicots in the Angiosperm Phylogeny Group II classification system. In the APG II circumscription, this order includes the families Fabaceae or legumes, Quillajaceae, Polygalaceae or milkworts, and Surianaceae. Under the Cronquist system and some other plant classification systems, the order Fabales contains only the family Fabaceae. In the classification system of Dahlgren the Fabales were in the superorder Fabiflorae with three families corresponding to the subfamilies of Fabaceae in APG II. The other families treated in the Fabales by the APG II classification were placed in separate orders by Cronquist, the Polygalaceae within its own order, the Polygalales, and the Quillajaceae and Surianaceae within the Rosales.

Laurales Order of flowering plants

The Laurales are an order of flowering plants. They are magnoliids, related to the Magnoliales.

Magnoliales Basal order of flowering plants

The Magnoliales are an order of flowering plants.

Dicotyledon Historical grouping of flowering plants

The dicotyledons, also known as dicots, are one of the two groups into which all the flowering plants or angiosperms were formerly divided. The name refers to one of the typical characteristics of the group, namely that the seed has two embryonic leaves or cotyledons. There are around 200,000 species within this group. The other group of flowering plants were called monocotyledons or monocots, typically having one cotyledon. Historically, these two groups formed the two divisions of the flowering plants.

Nymphaeales Order of flowering plants

The Nymphaeales are an order of flowering plants, consisting of three families of aquatic plants, the Hydatellaceae, the Cabombaceae, and the Nymphaeaceae. It is one of the three orders of basal angiosperms, an early-diverging grade of flowering plants. At least 10 morphological characters unite the Nymphaeales. Molecular synapomorphies are also known.

Rosidae

Under the International Code of Nomenclature for algae, fungi, and plants (ICN), Rosidae is a botanical name at the rank of subclass. Circumscription of the subclass will vary with the taxonomic system being used; the only requirement being that it includes the family Rosaceae.

Magnoliopsida

Magnoliopsida is a valid botanical name for a class of flowering plants. By definition the class will include the family Magnoliaceae, but its circumscription can otherwise vary, being more inclusive or less inclusive depending upon the classification system being discussed.

Piperales Order of flowering plants

Piperales is an order of flowering plants. It necessarily includes the family Piperaceae but other taxa have been included or disincluded variously over time. Well-known plants which may be included in this order include black pepper, kava, lizard's tail, birthwort, and wild ginger.

Ranunculales Basal order of flowering plants in the eudicots

Ranunculales is an order of flowering plants. Of necessity it contains the family Ranunculaceae, the buttercup amily, because the name of the order is based on the name of a genus in that family. Ranunculales belongs to a paraphyletic group known as the basal eudicots. It is the most basal clade in this group; in other words, it is sister to the remaining eudicots. Widely known members include poppies, barberries, and buttercups.

Proteales Order of eudicot flowering plants

Proteales is an order of flowering plants consisting of three families. The Proteales have been recognized by almost all taxonomists.

Illiciales Order of flowering plants

Illiciales is an order of flowering plants that is not recognized by the current most widely used system of plant classification, the Angiosperm Phylogeny Group's APG III system. The order was comprised differently in various systems of plant taxonomy, but is composed of 2-4 families of shrubs, trees, and lianas native to Australasia, south eastern Asia, and the southeastern United States. The families all contain species with essential oils, and flowers with a perianth with bracts, sepals, and petals incompletely distinguished from each other and not arranged in definite whorls. The families of the order had been variably placed in other orders in different taxonomies.

Geraniales Order of flowering plants in the rosid subclade of eudicots

Geraniales are a small order of flowering plants, included within the rosid subclade of eudicots. The largest family in the order is Geraniaceae with over 800 species. In addition, the order includes the smaller Francoaceae with about 40 species. Most Geraniales are herbaceous, but there are also shrubs and small trees.

Violales Order of eudicot flowering plants

Violales is a botanical name of an order of flowering plants and takes its name from the included family Violaceae and proposed by Lindley (1853). The name has been used in several systems, although some systems used the name Parietales for similar groupings. In the 1981 version of the influential Cronquist system, order Violales was placed in subclass Dilleniidae with a circumscription consisting of the families listed below. Some classifications such as that of Dahlgren placed the Violales in the superorder Violiflorae.

<i>Austrobaileya</i> Species of plant

Austrobaileya is the sole genus consisting of a single species that constitutes the entire flowering plant family Austrobaileyaceae. The species Austrobaileya scandens grows naturally only in the Wet Tropics rainforests of northeastern Queensland, Australia.

Nelumbonaceae Family of flowering plants

Nelumbonaceae is a family of aquatic flowering plants. Nelumbo is the sole extant genus, containing Nelumbo lutea, native to North America, and Nelumbo nucifera, widespread in Asia. At least four other genera, Nelumbites, Exnelumbites, Paleonelumbo, and Nelumbago, are known from fossils.

Asterids Clade of Eudicot Angiosperms

In the APG IV system (2016) for the classification of flowering plants, the name asterids denotes a clade. Well known plants in this clade include the common daisy, forget-me-nots, nightshades, the common sunflower, petunias, yacon, morning glory, sweet potato, coffee, lavender, lilac, olive, jasmine, honeysuckle, ash tree, teak, snapdragon, sesame, psyllium, garden sage, table herbs such as mint, basil, and rosemary, and rainforest trees such as Brazil nut.

Chloranthaceae Family of flowering plants

Chloranthaceae is a family of flowering plants (angiosperms), the only family in the order Chloranthales. It is not closely related to any other family of flowering plants, and is among the early-diverging lineages in the angiosperms. They are woody or weakly woody plants occurring in Southeast Asia, the Pacific, Madagascar, Central and South America, and the West Indies. The family consists of four extant genera, totalling about 77 known species according to Christenhusz and Byng in 2016. Some species are used in traditional medicine. The type genus is Chloranthus. The fossil record of the family, mostly represented by pollen such as Clavatipollenites, extends back to the dawn of the history of flowering plants in the Early Cretaceous, and have been found on all continents.

Trimeniaceae Family of flowering plants

Trimeniaceae is a family of flowering plants recognized by most taxonomists, at least for the past several decades. It is a small family of one genus, Trimenia, with eight known species of woody plants, bearing essential oils. The family is subtropical to tropical and found in Southeast Asia, eastern Australia and on several Pacific Islands.

Magnoliidae <i>sensu</i> Chase & Reveal

Magnoliidae is a subclass of Equisetopsida in the sense used by Mark W. Chase and James L. Reveal in their 2009 article "A phylogenetic classification of the land plants to accompany APG III." This subclass comprises the angiosperms or flowering plants.

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