Difference between revisions of "Ginkgo biloba"

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{{Taxobox
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{{SPlantbox
| color = lightgreen
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|familia=Ginkgoaceae
| name = ''Ginkgo''
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|genus=Ginkgo
| fossil_range = [[Permian]] - Recent
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|species=biloba
| status = EN
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|common_name=Ginkgo, Maidenhair Tree
| status_system = iucn2.3
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|habit=tree
| status_ref = <ref name="iucn">{{IUCN2006|assessors=Sun|year=1998|id=32353|title=Ginkgo biloba|downloaded=11 May 2006}} Listed as Endangered (EN B1+2c v2.3) </ref>
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|Min ht box=35
| image = Gingko-Blaetter.jpg
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|Min ht metric=ft
| image_width = 240px
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|Max ht box=80
| image_caption = Ginkgo leaf
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|Max ht metric=ft
| regnum = [[Plant]]ae
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|height_ref=Complete Landscaping - ISBN 9780376009272
| divisio = '''Ginkgophyta'''
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|poisonous=can be toxic
| classis = '''Ginkgoopsida'''
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|poison_ref=Wikipedia
| ordo = '''Ginkgoales'''
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|lifespan=perennial
| familia = '''Ginkgoaceae'''
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|exposure=sun
| genus = '''''Ginkgo'''''
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|water=moist, moderate
| species = '''''G. biloba'''''
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|water_ref=Complete Landscaping - ISBN 9780376009272
| binomial = ''Ginkgo biloba''
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|features=deciduous, flowers, fall color
| binomial_authority = [[Carolus Linnaeus|L.]]
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|flower_season=mid spring, late spring
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|Temp Metric=°F
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|min_zone=4
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|usda_ref=Complete Landscaping - ISBN 9780376009272
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|max_zone=8.5
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|image=Gingko-Blaetter.jpg
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|image_width=240
 +
|image_caption=Ginkgo leaf
 
}}
 
}}
Ginkgo (Chinese name). Syn., Salisburia. Ginkgoaceae, one of the segregates from the Coniferae. One species in northern China and Japan, the sole remainder of a more numerous tribe in geologic time; now widespread as a street and park tree and also prized for the edible seeds.
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'''Ginkgo''' ('''''Ginkgo biloba''''') also spelled '''gingko''', also known as the '''Maidenhair Tree''' after ''[[Adiantum]]'', is a unique [[species]] of [[tree]] with no close living relatives. It is one of the best-known examples of a [[living fossil]], because Ginkgoales other than ''G. biloba'' are not known from the fossil record after the [[Pliocene]].<ref name=ZhouZheng>Palaeobiology: The missing link in Ginkgo evolution, journal: Nature, volume 423, page 821</ref><ref name="ucmp">http://www.ucmp.berkeley.edu/seedplants/ginkgoales/ginkgofr.html</ref>
  
Tall tree, with wedge-shaped deciduous lvs.: fls. small and mostly dioecious; pistillate fl. solitary, the single naked ovule ripening into a drupe; staminate fls. in slender, loose catkins: fr. a drupe about 1 in. diam., containing a very large lenticular seed or kernel.
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[[File:Radziejowice ginkgo biloba01.jpg|left|thumb|Ginkgo tree in [[autumn]]]]
 
 
The '''Ginkgo''' ('''''Ginkgo biloba'''''; ''''銀杏'''' in Chinese), frequently misspelled as "Gingko", and also known as the '''Maidenhair Tree''', is a unique [[tree]] with no close living relatives. It is classified in its own division, the '''Ginkgophyta''', comprising the single class '''Ginkgoopsida''', order '''Ginkgoales''', family '''Ginkgoaceae''', genus '''''Ginkgo''''' and is the only [[extant|extant species]] within this group. It is one of the best known examples of a [[living fossil]]. In the past it has also been placed in the divisions [[Spermatophyta]] or [[Pinophyta]]. Ginkgo is a [[gymnosperm]]: its seeds are not protected by an [[ovary (plants)|ovary]] wall. The apricot-like structures produced by female ginkgo trees are technically not [[fruit]]s, but are the seeds having a shell that consists of a soft and fleshy section (the [[sarcotesta]]), and a hard section (the [[sclerotesta]]). 
 
 
 
For centuries it was thought to be extinct in the wild, but is now known to grow wild in at least two small areas in [[Zhejiang]] province in eastern [[China]], in the [[Tian Mu Shan Reserve]].  However, as this area has known human activity for over a thousand years, the wild status of ginkgos there is uncertain.
 
 
 
__TOC__
 
 
 
==Characteristics==
 
[[Image:Ginkgo biloba0.jpg|left|thumb|Ginkgo seeds and leaves]]
 
===General Morphology===
 
Ginkgos are medium-large [[deciduous]] trees, normally reaching a height of 20–35&nbsp;m (66-115 feet), with some specimens in China being over 50&nbsp;m (164 feet). The tree has an often angular crown and long, somewhat erratic branches, and is usually deep rooted and resistant to wind and snow damage. Young trees are often tall and slender, and sparsely branched; the crown becomes broader as the tree ages. During autumn, the leaves turn a bright yellow, then fall, sometimes within a short space of time (1–15&nbsp;days). A combination of resistance to disease, insect-resistant wood and the ability to form aerial roots and sprouts makes ginkgos very long-lived, with some specimens claimed to be more than 2,500&nbsp;years old: A 3,000 year-old ginkgo has been reported in [[Shandong]] province in China (Lewington and Parker, 183).
 
 
 
Some old Ginkgos produce aerial roots, known as ''chichi'' (Japanese; "[[nipple]]s") or ''zhong-ru'' (Chinese), which form on the undersides of large branches and grow downwards. Chichi growth is very slow, and may take hundreds of years to occur. The function, if any, of these thick aerial roots is unknown.
 
 
 
===Stem===
 
[[Image:Gingko biloba3.jpg|left|thumb|Ginkgo mature seeds and autumn leaf colour]]  
 
Ginkgo branches grow in length by growth of shoots with regularly spaced leaves, as seen on most trees.  From the [[axil]]s of these leaves, "spur shoots" (also known as short shoots) develop on second-year growth. Short shoots have very short internodes (so that several years' growth may only extend them by a centimeter or two) and their leaves are ordinarily unlobed.  They are short and knobby, and are arranged regularly on the branches except on first-year growth.  Because of the short internodes, leaves appear to be clustered at the tips of short shoots, and reproductive structures are formed only on them (see picture to above left—seeds and leaves can be viewed on short shoots). In Ginkgos, as in other plants that possess them, short shoots allow the formation of new leaves in the older parts of the crown. After a numb
 
er of years, a short shoot may change into a long (ordinary) shoot, or vice versa.
 
 
 
===Leaves===
 
[[Image:Ginkgo leaf closeup.jpg|100px|thumb|right|A closeup of a Ginkgo leaf]]
 
 
 
The [[leaf|leaves]] are unique among seed plants, being fan-shaped with veins radiating out into the leaf blade, sometimes bifurcating (splitting) but never [[anastomosis|anastomosing]] to form a network.  Two veins enter the leaf blade at the base and fork repeatedly in two; this is known as dichotomous venation. The leaves are usually 5-10 cm (2-4 inches), but sometimes up to 15 cm (6 inches) long. The old popular name "Maidenhair tree" is because the leaves resemble some of the pinnae of the [[Maidenhair fern]] ''Adiantum capillus-veneris''. 
 
 
 
Leaves of long shoots are usually notched or lobed, but only from the outer surface, between the veins. They are borne both on the more rapidly-growing branch tips, where they are alternate and spaced out, and also on the short, stubby spur shoots, where they are clustered at the tips.  During summer the leaves are a deep green, turning to brilliant yellow in the autumn.  They generally remain yellow for a time, then suddenly drop most of their leaves in a short period.<!--This repeats what was said above.  Maybe remove?-->
 
 
 
===Reproduction===
 
[[Image:Gingko_fg01.jpg|thumb|left|autumn leaves and seeds]]
 
Ginkgos are [[plant sexuality|dioecious]], with separate sexes, some trees being [[female]] and others being [[male]]. Male plants produce small [[conifer cone|pollen cones]] with [[sporophyll]]s each bearing two [[microsporangium|microsporangia]] spirally arranged around a central axis.
 
[[Image:Ginkgo-biloba-male.JPG|right|thumb|Ginkgo pollen cones]]
 
Female plants do not produce cones. Two [[ovule]]s are formed at the end of a stalk, and after [[pollination]], one or both develop into seeds. The seed is 1.5-2 cm long. Its outer layer (the [[sarcotesta]]) is light yellow-brown, soft, and [[fruit]]-like.
 
It is plum-like and attractive, but the seed coat contains [[butanoic acid]] and smells like rancid [[butter]] (which contains the same chemical) when fallen on the ground. Beneath the sarcotesta is the hard [[sclerotesta]] and a papery [[endotesta]] and [[nucellus]].
 
 
 
The fertilization of ginkgo seeds is by motile sperm; similar to cycads, ferns, mosses and the algae. It is a large sperm of about 250-300 micrometres, similar to the cycad which is a little larger.  It was first discovered by the Japanese botanist [[Sakugoro Hirase]] in the early 1900s.  The sperm has a complex multi-layered structure which is a continuous belt of basal bodies that form the base of several thousand flagella which actually have a cilia-like motion.  The flagella/cilia apparatus pulls the body of the sperm forwards.  But it has only a tiny distance to travel to the archegonia, of which there are usually two or three.  Two sperm are produced, one of which successfully fertilizes the ovule. Although it is widely held that fertilization of ginkgo seeds occurs just before or after they fall in early autumn, <ref>[http://mac122.icu.ac.jp/ginkgo/icho.html Brief Notes on Ginkgo biloba]</ref> <ref>[http://www.ucmp.berkeley.edu/seedplants/ginkgoales/ginkgomm.html Ginkgoales: More on Morphology]</ref> <ref>[http://www.ucmp.berkeley.edu/IB181/VPL/CorCon/CorCon2.html Laboratory IX -- ''Ginkgo'', ''Cordaites'', and the Conifers]</ref> embryos ordinarily occur in seeds just before and after they drop from the tree. <ref>Ben F. Holt, Gar W. Rothwell. Is Ginkgo biloba (Ginkgoaceae) Really an Oviparous Plant? American Journal of Botany, Vol. 84, No. 6 (Jun., 1997) , pp. 870-872</ref>
 
 
 
[[Image:Ginkgo embryo and gametophyte.jpg|thumb|left|Female gametophyte, dissected from a seed freshly shed from the tree, containing a well-developed embryo]]
 
 
 
==Name==
 
The name “Ginkgo” was a phonetic note for its (older) Chinese name “银果” ( [[pinyin]]: ''yínguo'') meaning “silver fruit”. The most well known names today are either “白果” ( [[pinyin]]: ''bái guǒ'') as “white fruit” or “銀杏” ({{lang|zh|銀杏}}, [[pinyin]]: ''yínxìng'')  as “silver [[apricot]]". The s
 
ame characters are used in [[Japanese language|Japanese]] and [[Korean language|Korean]] (where the ginkgo had been introduced from China).  The Japanese pronunciation is ''ichō'' while the Korean equivalent is ''eunhaeng'', both of which appear to be a loan from Chinese, though this is not certain (from the entry in the dictionary [[kojien|Kōjien]]). The Japanese characters used to write ''ginkgo'' look as though they could be read ''ginkyō'', and this was the name [[Engelbert Kaempfer]], the first [[Westerner]] to see the species in [[1690]], wrote down in his ''Amoenitates Exoticae'' (1712). However, his ''y'' was misread as a ''g'', and the misspelling stuck.
 
  
In modern Japanese, the characters are read either ''ichō'' (meaning the tree) or ''ginnan'' (meaning the seed); this latter reading appears to be based on the [[renjo|renjō]] (i.e., [[liaison (linguistics)|liaison]]) reading of the characters. The modern Chinese name for its shelled seeds is {{lang|zh|白果}} (Mandarin ''bái guǒ''), meaning "white fruit".
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Ginkgos are very large trees, normally reaching a height of 20–35 m (66–115 feet), with some specimens over 50 m (164 feet). The tree has an angular crown and long, somewhat erratic branches, and is usually deep rooted and resistant to wind and snow damage. Young trees are often tall and slender, and sparsely branched; the crown becomes broader as the tree ages. During autumn, the leaves turn a bright yellow, then fall, sometimes within a short space of time (1–15 days). A combination of resistance to disease, insect-resistant wood and the ability to form aerial roots and sprouts makes ginkgos long-lived, with some specimens claimed to be more than 2,500 years old.
  
== Prehistory ==
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Ginkgo is a relatively shade-intolerant species that (at least in cultivation) grows best in environments that are well-watered and well-drained.  The species shows a preference for disturbed sites; in the "semi-wild" stands at Tian Mu Shan, many specimens are found along stream banks, rocky slopes, and cliff edges.   Accordingly, Ginkgo retains a prodigious capacity for vegetative growth. It is capable of sprouting from embedded buds near the base of the trunk (lignotubers, or basal chi chi) in response to disturbances, such as soil erosion. Old individuals are also capable of producing aerial roots (chi chi) on the undersides of large branches in response to disturbances such as crown damage; these roots can lead to successful clonal reproduction upon contacting the soil.
[[Image:Fossil Plant Ginkgo.jpg|right|thumb|Fossil ''Ginkgo'' leaves from the Jurassic of England]]
 
The Ginkgo is a [[living fossil]], with fossils recognisably related to modern Ginkgo from the [[Permian]], dating back 270&nbsp;million years. They diversified and spread throughout [[Laurasia]] during the middle [[Jurassic]] and [[Cretaceous]], but became much rarer thereafter. By the [[Paleocene]], ''Ginkgo adiantoides'' was the only ''Ginkgo'' species left in the [[Northern Hemisphere]] (but see below) with a markedly different (but not well-documented) form persisting in the [[Southern Hemisphere]], and at the end of the [[Pliocene]] ''Ginkgo'' fossils disappeared from the [[Image:Ginkgo_adiantoides.jpg|thumb|left|''[[Ginkgo]] adiantoides'' Eocene fossil leaf from the Tranquille Shale of British Columbia, Canada.]]fossil record everywhere apart from a small area of central China where the modern species survived. It is in fact doubtful whether the Northern Hemisphere fossil species of ''Ginkgo'' can be reliably distinguished; given the slow pace of evolution in the genus, there may have been only 2 in total; what is today called ''G. biloba'' (including ''G. adiantoides''), and ''G. gardneri'' from the [[Paleocene]] of [[Scotland]].  
 
  
At least morphologically, ''G. gardneri'' and the Southern Hemisphere species are the only known post-Jurassic taxa that can be unequivocally recognised, the remainder may just as well have simply been [[ecotypes]] or [[subspecies]]. The implications would be that ''G. biloba'' had occurred over an extremely wide range, had remarkable genetic flexibility and though [[evolution|evolving]] genetically never showed much [[speciation]]. The occurrence of ''G. gardneri'', it seems a [[Caledonia]]n mountain endemic, and the somewhat greater diversity on the Southern Hemisphere, suggests that old mountain ranges on the Northern Hemisphere could hold other, presently undiscovered, fossil ''Ginkgo'' species. Since the distribution of ''Ginkgo'' was already relictual in late prehistoric times, the chances that ancient [[DNA]] from subfossils can shed any light on this problem seem remote. While it may seem improbable that a species may exist as a contiguous entity for many millions of years, many of the Ginkgo's life-history parameters fit. These are extreme longevity, slow reproduction rate, (in Cenozoic and later times) a wide, apparently contiguous, but steadily contracting distribution coupled with, as far as can be demonstrated from the fossil record, extreme ecological conservatism (being restricted to light soils around rivers), and a low population density.
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Ginkgo branches grow in length by growth of shoots with regularly spaced leaves, as seen on most trees. From the [[axil]]s of these leaves, "spur shoots" (also known as short shoots) develop on second-year growth. Short shoots have very short [[Internode (botany)|internode]]s (so they may grow only one or two centimeters in several years) and their leaves are usually unlobed. They are short and knobby, and are arranged regularly on the branches except on first-year growth. Because of the short internodes, leaves appear to be clustered at the tips of short shoots, and reproductive structures are formed only on them (see pictures below - seeds and leaves are visible on short shoots). In Ginkgos, as in other plants that possess them, short shoots allow the formation of new leaves in the older parts of the crown. After a number of years, a short shoot may change into a long (ordinary) shoot, or vice versa.
  
Ginkgophyta fossils have been classified in the following families and genera:
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[[File:GinkgoLeaves.jpg|left|thumb|Ginkgo leaves in [[autumn]]]]
*Ginkgoaceae
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The [[leaf|leaves]] are unique among seed plants, being fan-shaped with veins radiating out into the leaf blade, sometimes bifurcating (splitting) but never [[anastomosis|anastomosing]] to form a network.<ref name="More on Morphology">[http://www.ucmp.berkeley.edu/seedplants/ginkgoales/ginkgomm.html Ginkgoales: More on Morphology]</ref>  Two veins enter the leaf blade at the base and fork repeatedly in two; this is known as dichotomous venation.  The leaves are usually 5–10 cm (2-4 inches), but sometimes up to 15 cm (6 inches) long. The old popular name "Maidenhair tree" is because the leaves resemble some of the pinnae of the [[Maidenhair fern]] ''Adiantum capillus-veneris''.
**''Arctobaiera''
 
**''Baiera''
 
**''Eretmophyllum''
 
**''Ginkgo''
 
**''Ginkgoites''
 
**''Sphenobaiera''
 
**''Windwardia''
 
*Trichopityaceae
 
**''Trichopitys''
 
  
''Ginkgo'' has been used for classifying plants with [[Leaf|leaves]] that have more than four [[Leaf#Veins|veins]] per segment, while ''Baiera'' for those with less th
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Leaves of long shoots are usually notched or lobed, but only from the outer surface, between the veins. They are borne both on the more rapidly-growing branch tips, where they are alternate and spaced out, and also on the short, stubby spur shoots, where they are clustered at the tips.
an four veins per segment. ''Sphenobaiera'' has been used to classify plants with a broadly wedge-shaped leaf that lacks a distinct leaf stem. ''Trichopitys'' is distinguished by having multiple-forked leaves with cylindrical (not flattened) thread-like ultimate divisions; it is one of the earliest fossils ascribed to the Ginkgophyta.
 
  
==Cultivation and uses==
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In some areas, most intentionally planted Ginkgos are male [[cultivar]]s grafted onto plants propagated from seed, because the male trees will not produce the malodorous seeds. The popular cultivar 'Autumn Gold' is a clone of a male plant.
[[Image:Ginkgo Riverside, Illinois.JPG|left|thumb|Ginkgos along Harlem Avenue in [[Riverside, Illinois]] ]]
 
Ginkgo has long been cultivated in [[China]]; some planted trees at temples are believed to be over 1,500 years old. The first record of Europeans encountering it is in [[1690]] in Japanese temple gardens, where the tree was seen by the German botanist Engelbert Kaempfer. Because of its status in [[Buddhism]] and [[Confucianism]], the Ginkgo is also widely planted in Korea and parts of Japan; in both areas, some naturalization has occurred, with Ginkgos seeding into natural forests.
 
[[Image:Radziejowice ginkgo biloba01.jpg|right|thumb|Ginkgo tree in autumn]]
 
In some areas, notably the [[United States]], most intentionally-planted Ginkgos are male [[cultivar]]s grafted onto plants propagated from seed, because the male trees will not produce the malodorous seeds. The popular cultivar 'Autumn Gold' is a clone of a male plant.
 
  
The Ginkgo has the intriguing distinction of being one of the world's most urban-tolerant trees, often growing where other trees cannot survive. Some claim that only one tree species, the [[Ailanthus|Tree-of-heaven]], is as urban-tolerant. Ginkgos rarely suffer disease problems, even in urban conditions, and are attacked by few insects. For this reason, and for their general beauty, ginkgos are excellent urban and shade trees, and are widely planted along many streets. The ginkgo is the official tree of the city of [[Kumamoto]], and two leaves form the symbol of the [[University of Tokyo]], the main campus of which is famous for its numerous ginkgos. 
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Ginkgos adapt well to the urban environment, tolerating pollution and confined soil spaces.<ref name="Gilman">http://hort.ufl.edu/trees/GINBILB.pdf</ref> They rarely suffer disease problems, even in urban conditions, and are attacked by few insects.<ref name=Boland>Michigan Gardener's Guide, ISBN 1930604203</ref><ref name="SULIS">http://www.sustland.umn.edu/design/insect.htm</ref> For this reason, and for their general beauty, ginkgos are excellent urban and shade trees, and are widely planted along many streets.
[[Image:gingkotrail.jpg|left|thumb|Ginkgo leaves painted on an asphalt walkway to guide tourists to a ginkgo forest in [[Dongducheon]], [[South Korea]].]]
 
[[Image:Skku logo.png|right|thumb|In [[South Korea]], [[Sungkyunkwan University]]'s logo is a ginkgo leaf.  Its main campus features several gingko trees that were planted in [[1519]] and still stand today.]]
 
  
 
Ginkgos are also popular subjects for growing as [[penjing]] and [[bonsai]]; they can be kept artificially small and tended over centuries. Furthermore, the trees are easy to propagate from seed.
 
Ginkgos are also popular subjects for growing as [[penjing]] and [[bonsai]]; they can be kept artificially small and tended over centuries. Furthermore, the trees are easy to propagate from seed.
  
Extreme examples of the Ginkgo's tenacity may be seen in [[Hiroshima]], [[Japan]], where four trees growing between 1–2&nbsp;km from the [[1945]] [[atom bomb]] explosion were among the few living things in the area to survive the blast ([http://www.xs4all.nl/~kwanten/hiroshima.htm photos & details]). While almost all other plants (and animals) in the area were destroyed, the ginkgos, though charred, survived and were healthy. The trees are alive to this day.
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{{Inc|
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Ginkgo (Chinese name). Syn., Salisburia. Often misspelled as "Gingko", and also known as the '''Maidenhair Tree'''. Ginkgoaceae, one of the segregates from the Coniferae. One species in northern China and Japan, the sole remainder of a more numerous tribe in geologic time; now widespread as a street and park tree and also prized for the edible seeds.
  
===Culinary use===
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Tall tree, with wedge-shaped deciduous lvs.: fls. small and mostly dioecious; pistillate fl. solitary, the single naked ovule ripening into a drupe; staminate fls. in slender, loose catkins: fr. a drupe about 1 in. diam., containing a very large lenticular seed or kernel.
The nut-like gametophytes inside the seeds are esteemed in and outside of Asia, and are a traditional Chinese food. Called ''yín xìng'' ([[wikt:银|银]][[wikt:杏|杏]]; literally "silver almond") or ''bái guǒ'' ([[wikt:白|白]][[wikt:果|果]]; literally "white fruit"), Ginkgo nuts are used in [[congee]], and are often served at special occasions such as weddings and the [[Chinese New Year]] (as part of the vegetarian dish called [[Buddha's delight]]).  In Chinese culture, they are believed to have health benefits; some also consider them to have [[aphrodisiac]] qualities. Japanese cooks add Ginkgo seeds to dishes such as [[chawanmushi]], and cooked seeds are often eaten along with other dishes. The seeds are available canned, sold as "White Nuts", and can be found in many Asian food stores in the West. Usually only a few are added for a portion enough for ten people.  
 
  
When eaten by children, in large quantities (over 5&nbsp;seeds a day), or over a long period of time, the raw gametophyte (meat) of the seed can cause poisoning by MPN (4-methoxypyridoxine). MPN is heat-stable.
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Ginkgo biloba, Linn. (Salisburia adiantifolia, Smith). Ginkgo. Maidenhair Tree. Kew Tree. A straight, sparsely branched, usually slender tree, attaining a height of 60-80 ft.: lvs. 3-5,1-clustered, fan-shaped, divided at summit, with thickened margin, striated on both sides with numerous parallel veins: fls. dioecious; male catkins slender, stalked; females on long footstalks, in pairs, of which one usually aborts: fr. a drupe, consisting of an acrid, foul-smelling pulp surrounding a smooth, angular oval, cream-colored, thin-shelled, sweet-kerneled nut.—The ginkgo was intro. to Amer. early in the last century; it is generally successful on good soil in the eastern states as far north as E. Mass, and Cent. Mich., and along the St. Lawrence River in parts of Canada. It is of special value for solitary planting to secure picturesque effects. It is considerably planted in Washington, D. C., where it is growing in esteem as a street tree because of its upright habit and freedom from insect injury. Easily prop, from seed, stratified in autumn; varieties by budding and grafting. Several horticultural forms are recognized, including laciniata, pendula and variegata. The foul odor of the ripe frs., which continue to mature and drop during a period of some weeks, constitutes the chief objection to the species as a street tree, or near dwellings, and suggests the advisability of prop, from staminate trees by grafting or budding, for planting in such locations. The kernels, which have a sweetish, slightly resinous flavor, are highly esteemed for food in China and Japan, and are gathered from fruiting trees in Washington for such use by Chinese laundry- men.
Studies have demonstrated that convulsions caused by MPN can be prevented or terminated with pyridoxine.
 
  
Some people are sensitive to the chemicals in the sarcotesta, the outer fleshy coating. These people should handle the seeds with care when preparing the seeds for consumption, wearing disposable gloves. The symptoms are [[dermatitis]] or [[blister]]s similar to that caused by contact with [[Poison-ivy (plant)|poison-ivy]]. However, seeds with the fleshy coating removed are perfectly safe to handle.
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The word Ginkgo seems to be pronounced with a hard initial G in the orient, but in English a soft G should be used. The name is often spelled Gingko, but the other spelling is that used by Linnaeus.
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{{SCH}}
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}}
  
[[Image:Ginkgo-penjing-montreal-botanical-gardens.jpg|thumb|right|Ginkgo as [[penjing]] in the [[Montreal Botanical Garden]]]]
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==Cultivation==
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It is hardy to zone 4. It is in flower from April to May, and the seeds ripen from October to November. The flowers are dioecious (individual flowers are either male or female, but only one sex is to be found on any one plant so both male and female plants must be grown if seed is required) and are pollinated by Wind. The plant is not self-fertile.
  
===Medical uses===
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The plant prefers light (sandy), medium (loamy) and heavy (clay) soils and requires well-drained soil. The plant prefers acid, neutral and basic (alkaline) soils. It cannot grow in the shade. It requires dry or moist soil and can tolerate drought. It can tolerate atmospheric pollution.
The extract of the Ginkgo leaves contains [[flavonoid]] glycosides and terpenoids ([[ginkgolide]]s, [[bilobalide]]s) and has been used pharmaceutically. It has many alleged [[nootropic]] properties, and is mainly used as [[memory]] enhancer and anti-[[vertigo (medical)|vertigo]] agent. However, studies differ about its efficacy.  
 
  
Out of the many conflicting research results, Ginkgo extract seem to have three effects on the human body: it improves blood flow (including microcirculation in small capillaries) to most tissues and organs; it protects against oxidative cell damage from free radicals; and it blocks many of the effects of PAF (platelet aggregation, blood clotting) that have been related to the development of a number of cardiovascular, renal, respiratory and CNS (Central Nervous System) disorders. Ginkgo can be used for [[intermittent claudication]].
+
Succeeds in most soil types so long as they are well-drained[117, 200, 202], though it prefers a rather dry loam in a position sheltered from strong winds[11]. Some of the best specimens in Britain are found growing on soils over chalk or limestone[185]. Plants flower and fruit more reliably after hot summers or when grown in a warm sunny position[202]. Established plants are drought resistant[117], they also tolerate atmospheric pollution[117, 200]. Plants can grow in poor hard-packed soil, making the male forms good candidates for street planting[229]. Trees are often used for street planting in towns, only the males are used because the fruit from female plants has a nauseous smell. The fruit contains butanoic acid, it has the aroma of rancid butter[200]. Ginkgo is a very ornamental plant[1, 117] and there are several named forms[11, 200]. This species is the only surviving member of a family that was believed to be extinct until fairly recent times. It has probably remained virtually unchanged for at least 150 million years and might have been growing when the dinosaurs were roaming the earth[237]. It is exceptional in having motile sperm[185] and fertilization may not take place until after the seed has fallen from the tree[81]. This genus belongs to a very ancient order and has affinities with tree ferns and cycads[185]. The ginkgo is usually slow growing, averaging less than 30cm per year with growth taking place from late May to the end of August[185]. Growth is also unpredictable, in some years trees may not put on any new growth whilst in others there may be 1 metre of growth[185]. This variability does not seem to be connected to water or nutrient availability. Trees are probably long-lived in Britain, one of the original plantings (in 1758) is still growing and healthy at Kew (1993). Plants are not troubled by insects or diseases[132, 200], have they evolved a resistance?[132]. Ginkgo is a popular food and medicinal crop in China, the plants are often cultivated for this purpose and are commonly grown in and around temples. Plants are either male or female, one male plant can pollinate up to 5 females. It takes up to 35 years from seed for plants to come into bearing[117]. Prior to maturity the sexes can often be distinguished because female plants tend to have almost horizontal branches and deeply incised leaves whilst males have branches at a sharper angle to the trunk and their leaves are not so deeply lobed[132]. Branches of male trees can be grafted onto female frees in order to fertilize them. When a branch from a female plant was grafted onto a male plant at Kew it fruited prolifically[11]. Female trees have often been seen in various gardens with good crops of fruit[K]. Seeds are marked by two or three longitudinal ridges, it is said that those with two ridges produce female plants whilst those with three ridges produce male plants[178]. Trees can be coppiced[200]. They can also be pruned into a fan-shape for growing on walls[202]. Another report says that the trees dislike pruning and will often die back as a result[238].
  
A [[2004]] conference paper <ref name="alzheim">{{cite conference| author=L. Witkam and I. Ramzan| title=Ginkgo biloba in the treatment of Alzheimer’s disease: A miracle cure?| booktitle=From Cell to Society| year=2004}} [http://www.chs.usyd.edu.au/conf04/submit/minipost/bv-witka.pdf full text pdf]&nbsp;&nbsp;[http://www.chs.usyd.edu.au/conf04/ Conference page].</ref> summarizes how various trials indicate that Ginkgo shows promise in the treatment of [[Alzheimer's disease]], although further study is needed.
+
===Propagation===
 +
Seed - best sown as soon as it is ripe in a cold frame or in a sheltered outdoor bed[78, 80]. The seed requires stratification according to one report[78] whilst another says that stratification is not required[80] and that the seed can be sown in spring but that it must not have been allowed to dry out[80]. Germination is usually good to fair. Prick out the seedlings into individual pots when they are large enough to handle and grow them on in light shade in the greenhouse for their first year. Plant them out into their permanent positions in the following spring[78, 80] and consider giving them some protection from winter cold for their first winter outdoors[K]. Softwood cuttings in a frame in spring[238]. Cuttings of half-ripe wood, July/August in a frame. The cutting may not grow away in its first year but usually grows all right after that[113]. Cuttings of mature wood, December in a frame[200].
  
Ginkgo is commonly added to [[energy drink]]s, but the amount is typically [[angel dusting|so low]] it does not produce a noticeable effect, except perhaps via a [[placebo effect]] from Ginkgo being listed on the label.
+
===Pests and diseases===
  
====Side effects====
 
Ginkgo may have some undesirable effects, especially for individuals with blood circulation disorders and those taking [[anti-coagulant]]s such as [[aspirin]] and [[warfarin]], although recent studies have found that ginkgo has little or no effect on the anticoagulant properties or pharmacodynamics of warfarin<ref name="warfarin">{{cite journal | quotes=no | author= Xuemin Jiang ''et al''| title= Effect of ginkgo and ginger on the pharmacokinetics and pharmacodynamics of warfarin in healthy subjects | journal= British Journal of Clinical Pharmacology| year= 2005| volume= 59| issue= 4| pages= 425&ndash;432| url=http://www.blackwell-synergy.com/links/doi/10.1111/j.1365-2125.2005.02322.x }}</ref><ref name="review">{{cite journal | quotes=no | author= Ernst E, Canter PH, Coon JT| title= Does ginkgo biloba increase the risk of bleeding? A systematic review of case reports | journal= Perfusion| year= 2005| volume= 18| pages= 52&ndash;56 }}</ref>. Ginkgo should also not be used by people who are taking [[monoamine oxidase inhibitor]]s (MAOI) or by [[pregnant]] women without first consulting a doctor.
 
  
Ginkgo side effects and cautions include: possible increased risk of bleeding, gastrointestinal discomfort, nausea, vomiting, diarrhea, headaches, dizziness, and restlessness.
+
==Varieties==
 +
*'Fastigiata' - A very upright female form, it produces good crops of seeds when in the company of a male, though the seed is a bit smaller than the species[K].
 +
*'King of Dongting' - A female form, despite its name. This form is widely grown in China for its seed.
  
Ginkgo supplements are usually taken in the range of 40–2000&nbsp;mg per&nbsp;day. If any side effects are experienced, consumption should be halted immediately.
+
==Gallery==
  
==See also==
+
<gallery perrow=5>
*[[Antioxidant]]
+
Image:Ginkgo biloba0.jpg|Ginkgo seeds and leaves
*[[Herbalism]]
+
Image:Gingko biloba3.jpg|Ginkgo mature seeds and autumn leaf colour
*[[Naturopathic medicine]]
+
Image:Ginkgo leaf closeup.jpg|A closeup of a Ginkgo leaf
 +
Image:Gingko_fg01.jpg|autumn leaves and seeds
 +
Image:Ginkgo embryo and gametophyte.jpg|Female gametophyte, dissected from a seed freshly shed from the tree, containing a well-developed embryo
 +
Image:Fossil Plant Ginkgo.jpg|Fossil ''Ginkgo'' leaves from the Jurassic of England
 +
Image:Ginkgo_adiantoides.jpg|''[[Ginkgo]] adiantoides'' Eocene fossil leaf from the Tranquille Shale of British Columbia, Canada.
 +
Image:Ginkgo Riverside, Illinois.JPG|Ginkgos along Harlem Avenue in [[Riverside, Illinois]]
 +
Image:gingkotrail.jpg|Ginkgo leaves painted on an asphalt walkway to guide tourists to a ginkgo forest in [[Dongducheon]], [[South Korea]].
 +
Image:Skku logo.png|In [[South Korea]], [[Sungkyunkwan University]]'s logo is a ginkgo leaf.  Its main campus features several gingko trees that were planted in [[1519]] and still stand today.
 +
Image:Radziejowice ginkgo biloba01.jpg|Ginkgo tree in autumn
 +
Image:Ginkgo-penjing-montreal-botanical-gardens.jpg|Ginkgo as [[penjing]] in the [[Montreal Botanical Garden]]]]
 +
Image:Ginkgo-biloba-male.JPG|Ginkgo pollen cones
 +
</gallery>
  
 
==References==
 
==References==
<references />
+
<references/>
:4. Lewington, A., & Parker, E. (1999). ''Ancient Trees.'' London: Collins & Brown Ltd. ISBN 1-85585-704-9.
+
*[http://www.pfaf.org/database/plants.php?Ginkgo+biloba Plants for a Future] - source of some creative commons text
 +
*[[Standard Cyclopedia of Horticulture]], by L. H. Bailey, MacMillan Co., 1963
 +
<!--- xxxxx  *Flora: The Gardener's Bible, by Sean Hogan. Global Book Publishing, 2003. ISBN 0881925381  -->
 +
<!--- xxxxx *American Horticultural Society: A-Z Encyclopedia of Garden Plants, by Christopher Brickell, Judith D. Zuk. 1996. ISBN 0789419432  -->
 +
<!--- xxxxx  *Sunset National Garden Book. Sunset Books, Inc., 1997. ISBN 0376038608  -->
  
 
==External links==
 
==External links==
{{wikispecies|Ginkgo biloba}}
+
*{{wplink}}
{{commonscat|Ginkgo}}
 
*[http://www.xs4all.nl/~kwanten The Ginkgo Pages]: all aspects, in
 
English, German, French, Spanish and Dutch. This non-commercial homepage also provides a literature/reference page.
 
*[http://www.conifers.org/gi/gi/index.htm Gymnosperm Database]
 
*[http://www.ucmp.berkeley.edu/seedplants/ginkgoales/ginkgo.html  Info] by the [[University of California Museum of Paleontology]]
 
*[http://www.phytochemicals.info/ginkgo.php Phytochemicals in ginkgo]
 
*[http://www.planet-weimar.de/english/index.html The Ginkgo Museum], [[Weimar, Germany]]
 
*[http://www.ottawahort.org/ginkgo.htm Growing Ginkgoes from seed]: by the Ottawa Horticultural Society
 
*[http://faculty.washington.edu/chudler/ginkgo.html Neuroscience for kids]: Refers to JAMA studies on efficacy
 
*[http://www.cas.vanderbilt.edu/bioimages/species/frame/gibi2.htm ''Ginkgo biloba'' images at bioimages.vanderbilt.edu]
 
*[http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=pubmed&dopt=Abstract&list_uids=9611693 Ginkgo biloba for antidepressant-induced sexual dysfunction]
 
*[http://nccam.net/health/ginkgo/ Ginkgo] Fact Sheet
 
*[http://www.cirrusimage.com/tree_Ginkgo.htm Ginkgo biloba] Large format diagnostic photos, information.
 
__notoc__
 
  
[[Category:Gymnosperms]]
+
{{stub}}
[[Category:Japanese words and phrases]]
+
__NOTOC__
[[Category:Living fossils]]
 
[[Category:Medicinal plants]]
 
[[Category:Horticulture]]
 

Latest revision as of 18:54, 8 May 2011


Ginkgo leaf


Plant Characteristics
Habit   tree

Height: 35 ft"ft" can not be assigned to a declared number type with value 35. to 80 ft"ft" can not be assigned to a declared number type with value 80.
Lifespan: perennial
Poisonous: can be toxic
Bloom: mid spring, late spring
Cultivation
Exposure: sun
Water: moist, moderate
Features: deciduous, flowers, fall color
USDA Zones: 4 to 8.5
Scientific Names

Ginkgoaceae >

Ginkgo >

biloba >


Ginkgo (Ginkgo biloba) also spelled gingko, also known as the Maidenhair Tree after Adiantum, is a unique species of tree with no close living relatives. It is one of the best-known examples of a living fossil, because Ginkgoales other than G. biloba are not known from the fossil record after the Pliocene.[1][2]

Ginkgo tree in autumn

Ginkgos are very large trees, normally reaching a height of 20–35 m (66–115 feet), with some specimens over 50 m (164 feet). The tree has an angular crown and long, somewhat erratic branches, and is usually deep rooted and resistant to wind and snow damage. Young trees are often tall and slender, and sparsely branched; the crown becomes broader as the tree ages. During autumn, the leaves turn a bright yellow, then fall, sometimes within a short space of time (1–15 days). A combination of resistance to disease, insect-resistant wood and the ability to form aerial roots and sprouts makes ginkgos long-lived, with some specimens claimed to be more than 2,500 years old.

Ginkgo is a relatively shade-intolerant species that (at least in cultivation) grows best in environments that are well-watered and well-drained. The species shows a preference for disturbed sites; in the "semi-wild" stands at Tian Mu Shan, many specimens are found along stream banks, rocky slopes, and cliff edges. Accordingly, Ginkgo retains a prodigious capacity for vegetative growth. It is capable of sprouting from embedded buds near the base of the trunk (lignotubers, or basal chi chi) in response to disturbances, such as soil erosion. Old individuals are also capable of producing aerial roots (chi chi) on the undersides of large branches in response to disturbances such as crown damage; these roots can lead to successful clonal reproduction upon contacting the soil.

Ginkgo branches grow in length by growth of shoots with regularly spaced leaves, as seen on most trees. From the axils of these leaves, "spur shoots" (also known as short shoots) develop on second-year growth. Short shoots have very short internodes (so they may grow only one or two centimeters in several years) and their leaves are usually unlobed. They are short and knobby, and are arranged regularly on the branches except on first-year growth. Because of the short internodes, leaves appear to be clustered at the tips of short shoots, and reproductive structures are formed only on them (see pictures below - seeds and leaves are visible on short shoots). In Ginkgos, as in other plants that possess them, short shoots allow the formation of new leaves in the older parts of the crown. After a number of years, a short shoot may change into a long (ordinary) shoot, or vice versa.

Ginkgo leaves in autumn

The leaves are unique among seed plants, being fan-shaped with veins radiating out into the leaf blade, sometimes bifurcating (splitting) but never anastomosing to form a network.[3] Two veins enter the leaf blade at the base and fork repeatedly in two; this is known as dichotomous venation. The leaves are usually 5–10 cm (2-4 inches), but sometimes up to 15 cm (6 inches) long. The old popular name "Maidenhair tree" is because the leaves resemble some of the pinnae of the Maidenhair fern Adiantum capillus-veneris.

Leaves of long shoots are usually notched or lobed, but only from the outer surface, between the veins. They are borne both on the more rapidly-growing branch tips, where they are alternate and spaced out, and also on the short, stubby spur shoots, where they are clustered at the tips.

In some areas, most intentionally planted Ginkgos are male cultivars grafted onto plants propagated from seed, because the male trees will not produce the malodorous seeds. The popular cultivar 'Autumn Gold' is a clone of a male plant.

Ginkgos adapt well to the urban environment, tolerating pollution and confined soil spaces.[4] They rarely suffer disease problems, even in urban conditions, and are attacked by few insects.[5][6] For this reason, and for their general beauty, ginkgos are excellent urban and shade trees, and are widely planted along many streets.

Ginkgos are also popular subjects for growing as penjing and bonsai; they can be kept artificially small and tended over centuries. Furthermore, the trees are easy to propagate from seed.


Read about Ginkgo biloba in the Standard Cyclopedia of Horticulture 

Ginkgo (Chinese name). Syn., Salisburia. Often misspelled as "Gingko", and also known as the Maidenhair Tree. Ginkgoaceae, one of the segregates from the Coniferae. One species in northern China and Japan, the sole remainder of a more numerous tribe in geologic time; now widespread as a street and park tree and also prized for the edible seeds.

Tall tree, with wedge-shaped deciduous lvs.: fls. small and mostly dioecious; pistillate fl. solitary, the single naked ovule ripening into a drupe; staminate fls. in slender, loose catkins: fr. a drupe about 1 in. diam., containing a very large lenticular seed or kernel.

Ginkgo biloba, Linn. (Salisburia adiantifolia, Smith). Ginkgo. Maidenhair Tree. Kew Tree. A straight, sparsely branched, usually slender tree, attaining a height of 60-80 ft.: lvs. 3-5,1-clustered, fan-shaped, divided at summit, with thickened margin, striated on both sides with numerous parallel veins: fls. dioecious; male catkins slender, stalked; females on long footstalks, in pairs, of which one usually aborts: fr. a drupe, consisting of an acrid, foul-smelling pulp surrounding a smooth, angular oval, cream-colored, thin-shelled, sweet-kerneled nut.—The ginkgo was intro. to Amer. early in the last century; it is generally successful on good soil in the eastern states as far north as E. Mass, and Cent. Mich., and along the St. Lawrence River in parts of Canada. It is of special value for solitary planting to secure picturesque effects. It is considerably planted in Washington, D. C., where it is growing in esteem as a street tree because of its upright habit and freedom from insect injury. Easily prop, from seed, stratified in autumn; varieties by budding and grafting. Several horticultural forms are recognized, including laciniata, pendula and variegata. The foul odor of the ripe frs., which continue to mature and drop during a period of some weeks, constitutes the chief objection to the species as a street tree, or near dwellings, and suggests the advisability of prop, from staminate trees by grafting or budding, for planting in such locations. The kernels, which have a sweetish, slightly resinous flavor, are highly esteemed for food in China and Japan, and are gathered from fruiting trees in Washington for such use by Chinese laundry- men.

The word Ginkgo seems to be pronounced with a hard initial G in the orient, but in English a soft G should be used. The name is often spelled Gingko, but the other spelling is that used by Linnaeus. CH


The above text is from the Standard Cyclopedia of Horticulture. It may be out of date, but still contains valuable and interesting information which can be incorporated into the remainder of the article. Click on "Collapse" in the header to hide this text.


Cultivation

It is hardy to zone 4. It is in flower from April to May, and the seeds ripen from October to November. The flowers are dioecious (individual flowers are either male or female, but only one sex is to be found on any one plant so both male and female plants must be grown if seed is required) and are pollinated by Wind. The plant is not self-fertile.

The plant prefers light (sandy), medium (loamy) and heavy (clay) soils and requires well-drained soil. The plant prefers acid, neutral and basic (alkaline) soils. It cannot grow in the shade. It requires dry or moist soil and can tolerate drought. It can tolerate atmospheric pollution.

Succeeds in most soil types so long as they are well-drained[117, 200, 202], though it prefers a rather dry loam in a position sheltered from strong winds[11]. Some of the best specimens in Britain are found growing on soils over chalk or limestone[185]. Plants flower and fruit more reliably after hot summers or when grown in a warm sunny position[202]. Established plants are drought resistant[117], they also tolerate atmospheric pollution[117, 200]. Plants can grow in poor hard-packed soil, making the male forms good candidates for street planting[229]. Trees are often used for street planting in towns, only the males are used because the fruit from female plants has a nauseous smell. The fruit contains butanoic acid, it has the aroma of rancid butter[200]. Ginkgo is a very ornamental plant[1, 117] and there are several named forms[11, 200]. This species is the only surviving member of a family that was believed to be extinct until fairly recent times. It has probably remained virtually unchanged for at least 150 million years and might have been growing when the dinosaurs were roaming the earth[237]. It is exceptional in having motile sperm[185] and fertilization may not take place until after the seed has fallen from the tree[81]. This genus belongs to a very ancient order and has affinities with tree ferns and cycads[185]. The ginkgo is usually slow growing, averaging less than 30cm per year with growth taking place from late May to the end of August[185]. Growth is also unpredictable, in some years trees may not put on any new growth whilst in others there may be 1 metre of growth[185]. This variability does not seem to be connected to water or nutrient availability. Trees are probably long-lived in Britain, one of the original plantings (in 1758) is still growing and healthy at Kew (1993). Plants are not troubled by insects or diseases[132, 200], have they evolved a resistance?[132]. Ginkgo is a popular food and medicinal crop in China, the plants are often cultivated for this purpose and are commonly grown in and around temples. Plants are either male or female, one male plant can pollinate up to 5 females. It takes up to 35 years from seed for plants to come into bearing[117]. Prior to maturity the sexes can often be distinguished because female plants tend to have almost horizontal branches and deeply incised leaves whilst males have branches at a sharper angle to the trunk and their leaves are not so deeply lobed[132]. Branches of male trees can be grafted onto female frees in order to fertilize them. When a branch from a female plant was grafted onto a male plant at Kew it fruited prolifically[11]. Female trees have often been seen in various gardens with good crops of fruit[K]. Seeds are marked by two or three longitudinal ridges, it is said that those with two ridges produce female plants whilst those with three ridges produce male plants[178]. Trees can be coppiced[200]. They can also be pruned into a fan-shape for growing on walls[202]. Another report says that the trees dislike pruning and will often die back as a result[238].

Propagation

Seed - best sown as soon as it is ripe in a cold frame or in a sheltered outdoor bed[78, 80]. The seed requires stratification according to one report[78] whilst another says that stratification is not required[80] and that the seed can be sown in spring but that it must not have been allowed to dry out[80]. Germination is usually good to fair. Prick out the seedlings into individual pots when they are large enough to handle and grow them on in light shade in the greenhouse for their first year. Plant them out into their permanent positions in the following spring[78, 80] and consider giving them some protection from winter cold for their first winter outdoors[K]. Softwood cuttings in a frame in spring[238]. Cuttings of half-ripe wood, July/August in a frame. The cutting may not grow away in its first year but usually grows all right after that[113]. Cuttings of mature wood, December in a frame[200].

Pests and diseases

Varieties

  • 'Fastigiata' - A very upright female form, it produces good crops of seeds when in the company of a male, though the seed is a bit smaller than the species[K].
  • 'King of Dongting' - A female form, despite its name. This form is widely grown in China for its seed.

Gallery

References

  1. Palaeobiology: The missing link in Ginkgo evolution, journal: Nature, volume 423, page 821
  2. http://www.ucmp.berkeley.edu/seedplants/ginkgoales/ginkgofr.html
  3. Ginkgoales: More on Morphology
  4. http://hort.ufl.edu/trees/GINBILB.pdf
  5. Michigan Gardener's Guide, ISBN 1930604203
  6. http://www.sustland.umn.edu/design/insect.htm

External links