Magnolia

Magnolia
Magnolia x wieseneri
Magnolia x wieseneri
Scientific classification
Kingdom: Plantae
(unranked): Angiosperms
(unranked): Magnoliids
Order: Magnoliales
Family: Magnoliaceae
Genus: Magnolia
L.
Species

See text

Magnolia is a large genus of about 210[1] flowering plant species in the subclass Magnolioideae of the family Magnoliaceae.

The natural range of Magnolia species is a disjunct distribution, with a main center in east and southeast Asia and a secondary center in eastern North America, Central America, the West Indies, and some species in South America. Today many species of Magnolia and an ever-increasing number of hybrids can also be found as ornamentals in large parts of North America, Europe, Australia and New Zealand. The genus is named after French botanist Pierre Magnol. Known as kepelan in Indonesia, this wood is used for making furniture and carved panels and never for statues.

Magnolia is an ancient genus. Having evolved before bees appeared, the flowers developed to encourage pollination by beetles. As a result, the carpels of Magnolia flowers are tough, to avoid damage by eating and crawling beetles. Fossilised specimens of M. acuminata have been found dating to 20 million years ago, and of plants identifiably belonging to the Magnoliaceae dating to 95 million years ago. Another primitive aspect of Magnolias is their lack of distinct sepals or petals. The term tepal has been coined to refer to the intermediate element that Magnolia has instead. Magnolias are used as food plants by the larvae of some Lepidoptera species, including Giant Leopard Moth.

Magnolia grandiflora is the official state flower of both Mississippi and Louisiana. For this reason, it has become a symbol of support for the regions most heavily damaged by Hurricane Katrina in the late summer of 2005 (for example, presenters at the 2005 Emmy Awards on September 18, 2005, wore magnolias on their lapels, as did host Ellen DeGeneres, a New Orleans native). The flower's abundance in Mississippi is reflected in its nickname of "Magnolia State". The magnolia is also the official state tree of Mississippi.

One of the oldest nicknames for Houston, Texas, U.S.A. is "The Magnolia City" due to the abundance of magnolias growing along Buffalo Bayou.

Contents

Origin of the name Magnolia

In 1703 Charles Plumier (1646-1704) described a flowering tree from the island of Martinique in his Genera[2]. He gave the species, known locally as 'Talauma', the genus name Magnolia, after Pierre Magnol. The English botanist William Sherard, who studied botany in Paris under Joseph Pitton de Tournefort, a pupil of Magnol, was most probably the first after Plumier to adopt the genus name Magnolia. He was at least responsible for the taxonomic part of Johann Jacob Dillenius's Hortus Elthamensis[3] and of Mark Catesby's famous Natural history of Carolina[4]. These were the first works after Plumier's Genera that used the name Magnolia, this time for some species of flowering trees from temperate North America.

Carolus Linnaeus, who was familiar with Plumier's Genera, adopted the genus name Magnolia in 1735 in his first edition of Systema naturae, without a description but with a reference to Plumier's work. In 1753, he took up Plumier's Magnolia in the first edition of Species plantarum. Since Linnaeus never saw an herbarium specimen (if there ever was one) of Plumier's Magnolia and had only his description and a rather poor picture at hand, he must have taken it for the same plant which was described by Catesby in his 1730 Natural History of Carolina. He placed it in the synonymy of Magnolia virginiana variety foetida, the taxon now known as Magnolia grandiflora.

The species that Plumier originally named Magnolia was later described as Annona dodecapetala by Lamarck[5], and has since been named Magnolia plumieri and Talauma plumieri (and still a number of other names) but is now known as Magnolia dodecapetala[6].

Early references and descriptions

Magnolias have long been known and used in China. References to their medicinal qualities go back to as early as 1083[7]. After the Spanish conquest of Mexico, Philip II commissioned his court physician Francisco Hernandez in 1570 to undertake a scientific expedition. Hernandez made numerous descriptions of plants, accompanied by drawings, but publication was delayed and hampered by a series of accidents. Between 1629 and 1651 the material was re-edited by members of the Accademia dei Lincei and issued (1651) in three editions as Nova plantarum historia Mexicana.

This work contains a drawing of a plant under the vernacular name Eloxochitl, that is most likely Magnolia macrophylla subsp. dealbata. It is possibly the first-ever description of a Magnolia that was seen in the Western World[8]. It is unclear whether there are early descriptions made by English or French missionaries who were sent to North America, but the first introduction of a Magnolia into Europe is well documented. It was the missionary and plant collector John Banister (1654-1693) who sent back Laurus tulipifera, foliis subtus ex cinereo aut argenteo purpurascentibus[9] from Virginia in 1688, to Henry Compton, the Bishop of London. This species is now known as Magnolia virginiana (Sweetbay magnolia). Thus, a plant collector had shipped the first Magnolia from North America to Europe before Charles Plumier discovered his Talauma on Martinique and gave it the name Magnolia[10].

Nomenclature and classification

When Linnaeus took up Magnolia in his Species plantarum (1753), he created a lemma of only one species: Magnolia virginiana. Under that species he described five varieties (glauca, foetida, grisea, tripetala and acuminata). In the tenth edition of Systema naturae (1759), he merged grisea with glauca, and raised the four remaining varieties to species status[11].

By the end of the 18th century, botanists and plant hunters exploring Asia began to name and describe the Magnolia species from China and Japan. The first Asiatic species to be described by western botanists were Magnolia denudata and Magnolia liliiflora[12], and Magnolia coco and Magnolia figo[13]. Soon after that, in 1794, Carl Peter Thunberg collected and described Magnolia obovata from Japan and at roughly the same time Magnolia kobus was also first collected[14].

With the number of species increasing, the genus was divided into the two subgenera Magnolia and Yulania. Magnolia contains the American evergreen species Magnolia grandiflora, which is of horticultural importance, especially in the United States, and Magnolia virginiana, the type species. Yulania contains several deciduous Asiatic species, such as Magnolia denudata and Magnolia kobus, which have become horticulturally important in their own right and as parents in hybrids. Classified in Yulania, is also the American deciduous Magnolia acuminata (Cucumber tree), which has recently attained greater status as the parent which is responsible for the yellow flower colour in many new hybrids.

Relations in the family Magnoliaceae have been puzzling taxonomists for a long time. Because the family is quite old and has survived many geological events (such as ice ages, mountain formation and continental drift), its distribution has become scattered. Some species or groups of species have been isolated for a long time, while others could stay in close contact. To create divisions in the family (or even within the genus Magnolia), solely based upon morphological characters, has proven to be a nearly impossible task[15].

By the end of the 20th century, DNA sequencing had become available as a method of large scale research on phylogenetic relationships. Several studies, including studies on many species in the family Magnoliaceae, were carried out to investigate relationships[16][17][18]. What these studies all revealed was that genus Michelia and Magnolia subgenus Yulania were far more closely allied to each other than either one of them was to Magnolia subgenus Magnolia. These phylogenetic studies were supported by morphological data[19].

As nomenclature is supposed to reflect relationships, the situation with the species names in Michelia and Magnolia subgenus Yulania was undesirable. Taxonomically there are three choices; 1: to join Michelia and Yulania species in a common genus, not being Magnolia (for which the name Michelia has priority); 2: to raise subgenus Yulania to generic rank, leaving Michelia names and subgenus Magnolia names untouched; or 3: to join Michelia with genus Magnolia into genus Magnolia s.l. (a big genus). Magnolia subgenus Magnolia can not be renamed because it contains Magnolia virginiana, the type species of the genus and of the family. Not many Michelia species have so far become horticulturally or economically important, apart for their wood. Both subgenus Magnolia and subgenus Yulania include species of major horticultural importance, and a change of name would be very undesirable for many people, especially in the horticultural branch. In Europe, Magnolia even is more or less a synonym for Yulania, since most of the cultivated species on this continent have Magnolia (Yulania) denudata as one of their parents. Most taxonomists who acknowledge close relations between Yulania and Michelia therefore support the third option and join Michelia with Magnolia.

The same goes, mutatis mutandis, for the (former) genera Talauma and Dugandiodendron, which are then placed in subgenus Magnolia, and genus Manglietia, which could be joined with subgenus Magnolia or may even earn the status of an extra subgenus. Elmerrillia seems to be closely related to Michelia and Yulania, in which case it will most likely be treated in the same way as Michelia is now. The precise nomenclatural status of small or monospecific genera like Kmeria, Parakmeria, Pachylarnax, Manglietiastrum, Aromadendron, Woonyoungia, Alcimandra, Paramichelia and Tsoongiodendron remains uncertain. Taxonomists who merge Michelia into Magnolia tend to merge these small genera into Magnolia s.l. as well. At present, western botanists tend toward a big Magnolia genus, whereas many Chinese botanists still recognize the different small genera.

Selected species of Magnolia

Note: the following list only includes temperate species; many other species occur in tropical areas. For a full list, see the Magnolia Society list

Uses

In general, Magnolia is a genus which has attracted a lot of horticultural interest. Hybridisation has been immensely successful in combining the best aspects of different species to give plants which flower at an earlier age than the species themselves, as well as having more impressive flowers. One of the most popular garden magnolias is a hybrid, M. x soulangeana (Saucer magnolia; hybrid M. liliiflora x M. denudata).

Medicinal uses

The bark from M. officinalis has long been used in traditional Chinese medicine, where it is known as hou po (厚朴). In Japan, kōboku, M. obovata has been used in a similar manner. The aromatic bark contains magnolol and honokiol, two polyphenolic compounds that have demonstrated anti-anxiety and anti-angiogenic properties. Magnolia bark also has been shown to reduce allergic and asthmatic reactions.[20][21]

Magnolia has attracted the interest of the dental research community because magnolia bark extract inhibits many of the bacteria responsible for caries and periodontal disease.[22][23] In addition, the constituent magnolol interferes with the action of glucosyltransferase, an enzyme needed for the formation of bacterial plaque.[24][25]

Danger of extinction

On January 18, 2008, the Botanic Gardens Conservation International (representing botanic gardens in 120 countries) stated that "400 medicinal plants are at risk of extinction, from over-collection and deforestation, threatening the discovery of future cures for disease." These included Yew trees (the bark is used for cancer drugs, paclitaxel); Hoodia (from Namibia, source of weight loss drugs); and half of all Magnolias (used as Chinese medicine for 5,000 years to fight cancer, dementia and heart disease); and Autumn crocus (for gout).[26] The WHO estimates that as many as 80% of the world's population depend on traditional medicine for their primary health care needs.[27]

Gallery

References

  1. ↑ The number of species in the genus Magnolia depends on the taxonomic view that one takes up. Recent molecular and morphological research shows that former genera Talauma, Dugandiodendron, Manglietia, Michelia, Elmerrillia, Kmeria, Parakmeria, Pachylarnax (and a small number of monospecific genera) all belong within the same genus, Magnolia s.l. (s.l. = sensu lato: 'in a broad sense', as opposed to s.s. = sensu stricto: 'in a narrow sense'). The genus Magnolia s.s. contains about 120 species. See the section Nomenclature and classification in this article.
  2. ↑ Plumier, C. (1703) Nova plantarum Americanarum genera. Paris. [New genera of American plants].
  3. ↑ Dillenius, J.J. (1732), Hortus Elthamensis, seu plantarum rariorum quas in horto suo Elthami in Cantio coluit vir ornamentissimus et praestantissimus Jacobus Sherard. London [The garden of Eltham, or rather about the rare plants that the most distinguished and prominent man Jacob Sherard grows in his garden in Eltham in Kent].
  4. ↑ Catesby, M. (1730), The Natural History of Carolina, Florida and the Bahama Islands, containing the figures of birds, beasts, fishes, serpents, insects and plants, Vol. 1. London.
  5. ↑ Lamarck, J.B.P.A. de (1786), Encyclopédie Méthodique Botanique, tome second: 127. Paris.
  6. ↑ Under the rule of priority, the first name that is validly published in Linnaeus' Species plantarum (1 May1753) or any other work of any other botanist after that, takes precedence over later names. Plumier's name was not a binomen and moreover published before Species plantarum, so it has no status. The first binomen that was published after 1753 was Lamarck's Annona dodecapetala (1786). Magnolia plumieri (1788) was published on a later date by Schwartz, and is treated as a later synonym, as are Magnolia fatiscens (1817; Richard), Talauma caerulea (Jaume St-Hilaire 1805) and Magnolia linguifolia (1822).
  7. ↑ Treseder (p. 9) quotes the "Cheng Lei Pen Tshao" (Reclassified Pharmaceutical Natural History).
  8. ↑ Treseder, N.G. (1978), Magnolias: 9-13.
  9. ↑ Laurel-leaved tulip tree, with leaves of which the under sides from ash grey or silvery grey turn into purplish.
  10. ↑ Treseder, N.G. (1978), Magnolias: 14.
  11. ↑ Magnolia glauca has the same type specimen as Magnolia virginiana and as the latter is the first valid name, the species is now called Magnolia virginiana (Sweetbay magnolia). Var. foetida was renamed Magnolia grandiflora, which is legitimate as the epithet foetida only has priority in its rank of variety. Magnolia grandiflora is the Southern magnolia. Magnolia tripetala (Umbrella magnolia) and Magnolia acuminata (Cucumber tree) are still recognized as species.
  12. ↑ Under these names the species were described by Desrousseaux in Lamarck's Encyclopédie Méthodique Botanique, tome troisieme (1792): 675. In the beginning of the 20th century, descriptions which seemed to represent the same species, were found in a work of the French naturalist P.J. Buc'hoz, Plantes nouvellement découvertes (1779), under the names Lassonia heptapeta and Lassonia quinquepeta. In 1934, the English botanist J.E. Dandy argued that these names had priority over the names by which both species had been known for over a century and hence from then on Magnolia denudata had to be named Magnolia heptapeta, Magnolia liliiflora should be changed into Magnolia quinquepeta. After a lengthy debate, specialist taxonomists decided that the Buc'hoz names were based on chimaeras (pictures constructed of elements of different species), and as Buc'hoz did not cite or preserve herbarium specimens, his names were ruled not to be acceptable.
  13. ↑ These species were published as Liriodendron coco and Liriodendron figo by J. de Loureiro in Flora Cochinchinensis (1790) and later (1817) transferred to Magnolia by A. P. de Candolle. Magnolia figo was soon after transferred to the genus Michelia.
  14. ↑ Magnolia kobus only received its name in 1814, when it was validly published by A.P. de Candolle. There has been much confusion about earlier attempts to validly publish this species, especially because descriptions and type specimens did not match.
  15. ↑ In 1927 J.E. Dandy accepted 10 genera in The genera of Magnoliaceae, Kew Bulletin 1927: 257-264. In 1984 Law Yuh-Wu proposed 15 in A preliminary study on the taxonomy of the family Magnoliaceae, Acta Phytotaxonomica Sinica 22: 89-109; in 2004 even 16, in Magnolias of China. This is not just about grouping some genera together where others do not; authors often choose different boundaries.
  16. ↑ Azuma, H., L.B. Thien & S. Kawano (1999), Molecular phylogeny of Magnolia (Magnoliaceae) inferred from cpDNA sequences and evolutionary divergence of the floral scents. Journal of Plant Research 112(1107): 291-306.
  17. ↑ Azuma, H., García-Franco, J.G., Rico-Gray, V., and Thien, L.B. (2001). Molecular phylogeny of the Magnoliaceae: the biogeography of tropical and temperate disjunctions. American Journal of Botany. 88: 2275-2285.
  18. ↑ Kim, S. et al. (2001), Phylogenetic relationships in family Magnoliaceae inferred from ndhF sequences. American Journal of Botany. 88(4): 717-728.
  19. ↑ Figlar, R.B. (2000), Proleptic branch initiation in Michelia and Magnolia subgenus Yulania provides basis for combinations in subfamily Magnolioideae. In: Liu Yu-hu et al., Proceedings of the International Symposium on the Family Magnoliaceae: 14-25, Science Press, Beijing.
  20. ↑ SupplementWatch library entry on Magnolia Bark
  21. ↑ Guangsong Pharmaceutical page on Magnolia Bark Extract
  22. ↑ "Compressed mints and chewing gum containing magnolia bark extract are effective against bacteria responsible for oral malodor.". J Agric Food Chem. 55 (23): 9465–9. 2007 November 14 Epub 2007 October 20. PMID : 17949053. 
  23. ↑ "Antimicrobial activity of magnolol and honokiol against periodontopathic microorganisms.". Planta Med.;(): 64 (4): 367–9. 1998 May. PMID : 9619121. 
  24. ↑ "The inhibitory effect of magnolol from Magnolia officinalis on glucosyltransferase.". Arch Oral Biol.;():. 51 (10): 899–905. 2006 October Epub 2006 June 22. PMID : 16797479. 
  25. ↑ "Effects of Magnolol and Honokiol on the activities of streptococcal glucosyltransferases both in solution and adsorbed on an experimental pellicle.". Lett Appl Microbiol. 39 (5): 459–65. 2004. PMID : 15482438. 
  26. ↑ Hawkins, B., (2008). "Plants for life: Medicinal plant conservation and botanic gardens". Botanic Gardens Conservation International, Richmond, U.K.
  27. ↑ "Guidelines on the Conservation of Medicinal Plants." (1993) Published by The International Union for Conservation of Nature and Natural Resources (IUCN), Gland, Switzerland, in partnership with The World Health Organization (WHO), Geneva, Switzerland, and World Wide Fund for Nature, Gland, Switzerland.

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