Magnolia Sieboldii 'Colossus'

''Magnolia'' is a large genus of about 210 to 340The 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. flowering plant species in the subfamily Magnolioideae of the family Magnoliaceae. It is named after French botanist Pierre Magnol.

''Magnolia'' is an ancient genus. Appearing before bees evolved, the flowers are theorized to have evolved to encourage pollination by beetles.
To avoid damage from pollinating beetles, the carpels of ''Magnolia'' flowers are extremely tough. Fossilized specimens of '' M. acuminata'' have been found dating to 20 million years ago, and fossils of plants identifiably belonging to the Magnoliaceae date to 95 million years ago. Another aspect of ''Magnolia'' considered to represent an ancestral state is that the flower bud is enclosed in a bract rather than in sepals; the perianth parts are undifferentiated and called tepals rather than distinct sepals and petals. ''Magnolia'' shares the tepal characteristic with several other flowering plants near the base of the flowering plant lineage such as ''Amborella'' and ''Nymphaea'' (as well as with many more recently derived plants such as '' Lilium'').

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.

Description

Magnolias are spreading, evergreen or deciduous trees or shrubs, characterised by large fragrant flowers which may be bowl-shaped or star-shaped, in shades of white, pink, purple, green or yellow. In deciduous species the blooms often appear before the leaves, in spring. Cone-like fruits are often produced in autumn.

As with all Magnoliaceae, the perianth is undifferentiated, with 9–15 tepals in three or more whorls. The flowers are bisexual with numerous adnate carpels and stamens are arranged in a spiral fashion on the elongated receptacle. The fruit dehisces along the dorsal sutures of the carpels. The pollen is monocolpate, and the embryo development is of the Polygonum type.

Taxonomists, including James E. Dandy in 1927, have long had an interest in observing fruits of Magnoliaceae and have often used the differences, or perceived differences, in fruit characters to justify systems for classification.

Taxonomy

History

Early

The name ''Magnolia'' first appeared in 1703 in the ''Genera''Plumier, C. (1703) ''Nova plantarum Americanarum genera''. Paris. ew genera of American plants of Charles Plumier (1646–1704), for a flowering tree from the island of Martinique (''talauma''). It was named after the French botanist Pierre Magnol. 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'' and of Mark Catesby's ''Natural History of Carolina, Florida and the Bahama Islands''. 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. The species that Plumier originally named ''Magnolia'' was later described as ''Annona dodecapetala'' by Lamarck, and has since been named ''Magnolia plumieri'' and ''Talauma plumieri'' (and still a number of other names) but is now known as ''Magnolia dodecapetala''.Under the rule of priority, the first name that is validly published in Linnaeus' ''Species Plantarum'' (1 May 1753) 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 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).

Carl 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''. There he described a monotypic genus, with the sole species being '' Magnolia virginiana''. Since Linnaeus never saw a 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'' var. ''fœtida'', the taxon now known as '' Magnolia grandiflora''. Under ''Magnolia virginiana'' Linnaeus described five varieties (''glauca'', ''fœtida'', ''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.''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. ''fœtida'' was renamed '' Magnolia grandiflora'', which is legitimate as the epithet ''fœtida'' 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.

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'', ''Magnolia liliiflora'',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's 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. ''Magnolia coco'' and ''Magnolia figo''.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''. 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.

Recent

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

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. 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.

As nomenclature is supposed to reflect relationships, the situation with the species names in ''Michelia'' and ''Magnolia'' subgenus ''Yulania'' was undesirable. Taxonomically, three choices are available:

# to join ''Michelia'' and ''Yulania'' species in a common genus, not being ''Magnolia'' (for which the name ''Michelia'' has priority);
# to raise subgenus ''Yulania'' to generic rank, leaving ''Michelia'' names and subgenus ''Magnolia'' names untouched, or;
# to join ''Michelia'' with genus ''Magnolia'' into genus ''Magnolia'' s.l. (a big genus).

''Magnolia'' subgenus ''Magnolia'' cannot be renamed because it contains ''M. 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

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