ginkgo

The ginkgo (Ginkgo biloba) is a living fossil, with fossils similar to the modern plant dating back to the Permian, 270 million years ago. The ancestor of the genus is estimated to have branched off from other gymnosperms about 325 million years ago, while the last common ancestor of today's only remaining species lived not earlier than 390,000 years ago.[https://pubmed.ncbi.nlm.nih.gov/29703145/ Ginkgo biloba's footprint of dynamic Pleistocene history dates back only 390,000 years ago] The closest living relatives of the clade are the cycads,Royer et al. (2003), p. 84. which share with the extant G. biloba the characteristic of motile sperm. Motile sperm is believed to be a basal trait of green plants, as it is also present in all non-seed plants such as ferns and mosses, as well as most green algae, which are believed to be the base of the green plant clade, the group in which the last common ancestor of land plants emerged. Motile sperm have been lost in all seed plants except for the ginkgo and the cycads, making it a shared conserved trait—a plesiomorphy—and implying these two groups themselves form a clade, sharing a common ancestor also with the trait, which diverged early from the rest of the seed plant lineage.

The time of this divergence is estimated to be extremely ancient, dating to the early Carboniferous.{{Cite journal|last1=Stull|first1=Gregory W.|last2=Qu|first2=Xiao-Jian|last3=Parins-Fukuchi|first3=Caroline|last4=Yang|first4=Ying-Ying|last5=Yang|first5=Jun-Bo|last6=Yang|first6=Zhi-Yun|last7=Hu|first7=Yi|last8=Ma|first8=Hong|last9=Soltis|first9=Pamela S.|last10=Soltis|first10=Douglas E.|last11=Li|first11=De-Zhu|date=July 19, 2021|title=Gene duplications and phylogenomic conflict underlie major pulses of phenotypic evolution in gymnosperms|url=https://www.nature.com/articles/s41477-021-00964-4|journal=Nature Plants|language=en|volume=7|issue=8|pages=1015–1025|doi=10.1038/s41477-021-00964-4|pmid=34282286 |bibcode=2021NatPl...7.1015S |s2cid=236141481 |issn=2055-0278}} Fossils attributable to the genus Ginkgo with reproductive organs similar to the modern species first appeared in the Middle Jurassic,{{Cite journal|last=Zhou|first=Zhi-Yan|date=March 2009|title=An overview of fossil Ginkgoales|url=https://linkinghub.elsevier.com/retrieve/pii/S1871174X0900002X|journal=Palaeoworld|language=en|volume=18|issue=1|pages=1–22|doi=10.1016/j.palwor.2009.01.001|quote=|url-access=subscription}} and the genus diversified and spread throughout Laurasia during the Jurassic and Early Cretaceous. It declined in diversity as the Cretaceous progressed with the extinction of species such as Ginkgo huolinhensis, and by the Palaeocene, only a few Ginkgo species, Ginkgo cranei and Ginkgo adiantoides, remained in the Northern Hemisphere, while a markedly different (and poorly documented) form persisted in the Southern Hemisphere.{{Citation needed|date=June 2013}} At the end of the Pliocene, Ginkgo fossils disappeared from the fossil record everywhere except in a small area of central China, where the modern species survived. It is doubtful whether the Northern Hemisphere fossil species of Ginkgo can be reliably distinguished. Given the slow pace of evolution and morphological similarity between members of the genus, there may have been only one or two species existing in the Northern Hemisphere through the entirety of the Cenozoic: present-day G. biloba (including G. adiantoides) and G. gardneri from the Palaeocene of Scotland.Royer et al. (2003), p. 85.

File:Fossil Plant Ginkgo.jpg leaves from the Jurassic of England]]

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 have been ecotypes or subspecies. The implications would be that G. biloba had occurred over an extremely wide range, had remarkable genetic flexibility and, though evolving genetically, never showed much speciation. 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. It displays extreme longevity and a slow reproduction rate. Additionally, in Cenozoic and later times, the ginkgo's distribution is wide and apparently contiguous, although steadily contracting. The fossil record shows extreme ecological conservatism as the niche of the ginkgo is restricted to disturbed streamside environments.Royer et al. (2003), p. 91.

Modern-day G. biloba grows best in well-watered and drained environments,Royer et al. (2003), p. 87. and the extremely similar fossil Ginkgo favoured similar environments. The sediment records at the majority of fossil Ginkgo localities indicate it grew primarily in disturbed environments along streams and levees. Ginkgo therefore presents an "ecological paradox" because, while it possesses some favourable traits for living in disturbed environments (clonal reproduction), many of its other life-history traits (slow growth, large seed size, late reproductive maturity) are the opposite of those exhibited by "younger", more-recently emerged plant species that thrive in disturbed settings.Royer et al. (2003), p. 92.

Given the slow rate of evolution of the genus, it is possible that Ginkgo represents a pre-angiosperm strategy for survival in disturbed streamside environments. Ginkgo evolved in an era before angiosperms (flowering plants), when ferns, cycads, and cycadeoids dominated disturbed streamside environments, forming a low, open, shrubby canopy. The large seeds of Ginkgo and its habit of "bolting"—growing to a height of {{approx}} {{convert|10|m|abbr=off|sigfig=1}} before elongating its side branches—may be adaptations to such an environment. Diversity in the genus Ginkgo dropped through the Cretaceous (along with that of ferns, cycads, and cycadeoids) at the same time the flowering plants were on the rise, which supports the notion that flowering plants, with their better adaptations to disturbance, displaced Ginkgo and its associates over time.Royer et al. (2003), p. 93.

Trichopitys heteromorpha from the earliest Permian of France, is one of the earliest fossils ascribed to the Ginkgophyta.{{Cite journal|last=Zhou|first=Zhi-Yan|date=March 2009 |title=An overview of fossil Ginkgoales |url=https://linkinghub.elsevier.com/retrieve/pii/S1871174X0900002X |journal=Palaeoworld|language=en |volume=18|issue=1|pages=1–22 |doi=10.1016/j.palwor.2009.01.001|url-access=subscription}} It had multiple-forked non-laminar leaves with cylindrical, thread-like ultimate divisions. Sphenobaiera (early Permian–Cretaceous) had wedge-shaped leaves divided into narrow dichotomously-veined lobes, lacking distinct petioles (leaf stalks). Baiera (Triassic–Jurassic) had similar multiple-lobed leaves but with petioles.{{cite book |first1=Thomas N. |last1=Taylor |first2=Edith I. |last2=Taylor |first3=Michael |last3=Krings |date=2009 |title=Palaeobotany: The biology and evolution of fossil plants |publisher=Elsevier |isbn=978-0-12-373972-8 }}{{rp|743-756}}

{{As of|2013|February}}, molecular phylogenetic studies have produced at least six different placements of Ginkgo relative to cycads, conifers, gnetophytes and angiosperms. The two most common are that Ginkgo is a sister to a clade composed of conifers and gnetophytes, and that Ginkgo and cycads form a clade within the gymnosperms. A 2013 study examined the reasons for the discrepant results and concluded that the best support was for the monophyly of Ginkgo and cycads.Wu et al. (2013)

The genus name is a mis‐transliteration of the Japanese pronunciation {{tlit|ja|gin kyo}} for the kanji {{langx|ja|銀杏|lit=silver apricot}}.{{Citation|last=Coombes|first=Allen J.|title=Dictionary of Plant Names|year=1994|location=London|publisher=Hamlyn Books|isbn=978-0-600-58187-1}} This name is adopted from Chinese, the name being found in Chinese herbology literature such as Daily Use Materia Medica ({{lang|zh|日用本草}}) (1329) and Compendium of Materia Medica ({{lang|zh|本草綱目}}) published in 1578.T. Hori, A historical survey of Ginkgo biloba based on Japanese and Chinese classical literatures, Plant Morphology, 2001, 31, 31–40

Despite its spelling, which is due to a complicated etymology including a transcription error, "ginkgo" is usually pronounced {{IPAc-en|ˈ|ɡ|ɪ|ŋ|k|oʊ}}, which has given rise to the common alternative spelling "gingko". The spelling pronunciation {{IPAc-en|ˈ|ɡ|ɪ|ŋ|k|g|oʊ}} is also documented in some dictionaries.{{Cite dictionary |url=http://www.lexico.com/definition/ginkgo |archive-url=https://web.archive.org/web/20200322182209/https://www.lexico.com/definition/ginkgo |url-status=dead |archive-date=22 March 2020 |title=ginkgo |dictionary=Lexico UK English Dictionary |publisher=Oxford University Press}}{{cite Merriam-Webster |ginkgo}}

Engelbert Kaempfer first introduced the spelling {{tlit|ja|ginkgo}} in his book Amoenitatum Exoticarum, taking it from Japanese herbalist {{lang|ja|{{ill|Tekisai Nakamura|ja|中村惕斎}}}} in his manuscript, {{lang|ja|{{ill|Kinmō Zu'i|ja|訓蒙図彙}}}}, acquired in Dejima between 1689–91. It is considered that he may have misspelled {{tlit|ja|ginkyo}} or {{tlit|ja|ginkio}} as {{tlit|ja|ginkgo}}. This misspelling was included by Carl Linnaeus in his book Mantissa plantarum IISee page 131 of Car. a Linné Mantissa plantarum: Generum editionis VI. et specierum editionis II, available at [https://www.biodiversitylibrary.org/item/137335#page/181/mode/1up] and has become the name of the tree's genus.{{cite web |last=Michel |first=Wolfgang |title=On Engelbert Kaempfer's 'Ginkgo' |pages=1–5 |publisher=Kyushu University |location=Fukuoka |year=2011 |orig-year=2005 |website=Research Notes Collections |url=https://catalog.lib.kyushu-u.ac.jp/opac_download_md/2898/Ginkgo_biloba2_revised_2011.pdf}}

In Korea, the seed flesh is eaten with rice.{{Cite web |last=Lee |first=Seongwoo |title=은행(銀杏) Fruit of the Ginkgo tree |url=https://encykorea.aks.ac.kr/Article/E0042928 |access-date=2023-11-06 |website=Encyclopedia of Korean Culture |language=ko}}

{{Reflist|30em}}

{{Refbegin}}

• {{cite journal |author=Dana L. Royer, Leo J. Hickey & Scott L. Wing |year=2003 |title=Ecological conservatism in the 'living fossil' Ginkgo |journal=Paleobiology |volume=29 |issue=1 |pages=84–104 |doi=10.1666/0094-8373(2003)029<0084:ECITLF>2.0.CO;2 |s2cid=19865243 |ref=Royer}}
• {{cite book |author=Thomas N. Taylor & Edith L. Taylor |year=1993 |title=The Biology and Evolution of Fossil Plants |location=Englewood Cliffs, NJ |publisher=Prentice Hall |isbn=0-13-651589-4 |ref=Taylor}}
• {{cite journal |author=Chung-Shien Wu, Shu-Miaw Chaw & Ya-Yi Huang |year=2013 |title=Chloroplast phylogenomics indicates that Ginkgo biloba is sister to cycads |journal=Genome Biology and Evolution |volume=5 |issue=1 |pages=243–254 |doi=10.1093/gbe/evt001 |pmid=23315384 |ref=Wu|pmc=3595029 }}

{{Refend}}

{{wikt|ginkgo}}

{{Medicinal herbs & fungi}}

{{Taxonbar|from=Q149461}}

{{Authority control}}

Category:Extant Permian first appearances

Category:Gymnosperm genera

Category:Permian plants

Category:Prehistoric gymnosperm genera

Category:Taxa named by Carl Linnaeus