View source for Metasequoia

{{Short description|Genus of conifers}}
{{About|the redwood genus, ''Metasequoia''|the software|Metasequoia (software)}}
{{Automatic taxobox
| fossil_range = {{Fossil range|94|0|[[Late Cretaceous]]–[[Recent]]}}
| image = SJSU Dawn Redwood.JPG
| taxon = Metasequoia
| authority = [[Hu Xiansu|Hu]] & [[Wan Chun Cheng|Cheng]]
| type_species = ''[[Metasequoia glyptostroboides]]''
| type_species_authority = Hu & Cheng
| subdivision_ranks = [[Species]]
| subdivision = *†''[[Metasequoia disticha|M. disticha]]''
* †''[[Metasequoia foxii|M. foxii]]''
* ''[[Metasequoia glyptostroboides|M. glyptostroboides]]''
* †''[[Metasequoia milleri|M. milleri]]''
* †''[[Metasequoia occidentalis|M. occidentalis]]''
}}

'''''Metasequoia''''', or '''dawn redwood''', is a genus of fast-growing [[coniferous]] trees, one of three species of [[pinophyta|conifers]] known as redwoods. The living species ''[[Metasequoia glyptostroboides]]'' is native to [[Lichuan, Hubei|Lichuan]] county in [[Hubei]] province, [[China]]. Although the shortest of the [[Sequoioideae|redwoods]], it grows to at least {{convert|165|ft|m|abbr=off|sp=us}} in height. Local villagers refer to the original tree from which most others derive as ''Shuǐshān'' (水杉), or "water fir", which is part of a local shrine. Since its rediscovery in 1944, the dawn redwood has become a popular ornamental, with examples found in various parks in a variety of countries. The [[genus]] was dominant near the North Pole during the [[Cretaceous]].

Together with ''[[Sequoia sempervirens]]'' (coast redwood) and ''[[Sequoiadendron giganteum]]'' (giant sequoia) of [[California]], ''Metasequoia'' is classified in the [[Cupressaceae]] subfamily [[Sequoioideae]]. ''M.&nbsp;glyptostroboides'' is the only living species in its genus, but three [[fossil]] species are known. Sequoioideae and several other genera have been transferred from the former family [[Taxodiaceae]] to Cupressaceae based on DNA analysis.<ref>{{cite journal |last1=Gadek |first1=Paul A. |last2=Alpers |first2=Deryn L. |last3=Heslewood |first3=Margaret M. |last4=Quinn |first4=Christopher J. |year=2000 |title=Relationships within Cupressaceae ''sensu lato'': a combined morphological and molecular approach |journal=[[American Journal of Botany]] |volume=87 |issue=7 |pages=1044–1057 |doi=10.2307/2657004 |jstor=2657004 |pmid=10898782 |doi-access=free}}</ref>

==Paleontology==
''Metasequoia'' redwood fossils are known from many areas in the [[Northern Hemisphere]]; more than 20 fossil species have been named (some were even identified as the genus ''Sequoia''), but are considered as just three species, ''[[Metasequoia foxii|M.&nbsp;foxii]]'', ''[[Metasequoia milleri|M.&nbsp;milleri]]'', and ''[[Metasequoia occidentalis|M.&nbsp;occidentalis]]''.<ref>{{cite book |author=Farjon |first=A. |title=Monograph of Cupressaceae and ''Sciadopitys'' |publisher=[[Royal Botanic Gardens, Kew]] |year=2005 |isbn=1-84246-068-4}}</ref> Fossils are known from the [[Cenomanian]] onwards. During the [[Paleocene]] and [[Eocene]], extensive forests of ''Metasequoia'' occurred as far north as [[Strathcona Fiord]] on [[Ellesmere Island]] and sites on [[Axel Heiberg Island]] (northern [[Canada]]) at around [[80th parallel north|80°&nbsp;N]] latitude.<ref>{{cite journal |last1=Williams |first1=Christopher J. |last2=Johnson |first2=Arthur H. |last3=LePage |first3=Ben A. |last4=Vann |first4=David R. |last5=Sweda |first5=Tatsuo |year=2003 |title=Reconstruction of Tertiary ''Metasequoia'' forests. II. Structure, biomass, and productivity of Eocene floodplain forests in the Canadian Arctic |url=http://edisk.fandm.edu/chris.williams/pubs/williams_etal_2003b.pdf |journal=[[Paleobiology (journal)|Paleobiology]] |volume=29 |issue=2 |pages=271–292 |doi=10.1666/0094-8373(2003)029<0271:ROTMFI>2.0.CO;2 |s2cid=131497232}}</ref> ''Metasequoia'' was likely [[deciduous]] by this time. Given that the high latitudes in this period were warm and tropical, it is hypothesized that the deciduous trait evolved in response to the unusual light availability patterns, not to major seasonal variations in temperature.<ref>{{cite journal |author=Chaney |first=Ralph W. |year=1948 |title=The bearing of the living ''Metasequoia'' on problems of Tertiary paleobotany |journal=Proceedings of the National Academy of Sciences |volume=34 |issue=11 |pages=503–515 |bibcode=1948PNAS...34..503C |doi=10.1073/pnas.34.11.503 |jstor=88221 |pmc=1079159 |pmid=16588827 |doi-access=free}}</ref> During three months in the summer, the sun would shine continuously, while three months of the winter would be complete darkness. It is also hypothesized that the change from [[evergreen]] to deciduous trait occurred before colonizing the high latitudes and was the reason ''Metasequoia'' was dominant in the north.<ref>{{cite book |author1=Richard Jagels  |author2=Maria A. Equiza  |name-list-style=amp |year=2005 |title=Competitive advantages of ''Metasequoia'' in warm high latitudes |pages=335–349}} In [[#LWY|LePage ''et al'' (2005)]].</ref>

Large petrified trunks and stumps of the extinct ''Metasequoia occidentalis'' (sometimes identified as ''Sequoia occidentalis'') also make up the major portion of Tertiary fossil plant material in the badlands of western [[North Dakota]].{{citation needed|date=April 2024}}

The trees are well known from late [[Cretaceous]] to [[Miocene]] strata, but no fossils are known after that. Before its discovery, the taxon was believed to have become extinct during the Miocene; when it was discovered [[wikt:extant|extant]], it was heralded as a "[[Lazarus taxon|living fossil]]".

==Appearance==
[[File:MetaseqLeaves.jpg|left|thumb|Dawn redwood foliage – note opposite arrangement]]
The bark and foliage are similar to ''[[Sequoia (genus)|Sequoia]]'', but ''Metasequoia'' is [[deciduous]] like ''[[Taxodium distichum]]'' (bald cypress), and, similarly, older specimens form wide buttresses on the lower trunk. It is a fast-growing tree to 130–150 feet (40–45 m) tall and 6 feet (2 m) in trunk diameter in cultivation so far (with the potential to grow even higher).{{citation needed|date=April 2024}}

The leaves are opposite, 0.4–1.25 inches (1–3&nbsp;cm.) long, and bright fresh green, turning foxy red-brown in fall. The [[pollen]] cones are 0.25 inch (6&nbsp;mm) long, produced on long spikes in early spring; they are only produced on trees growing in regions with hot summers. The [[conifer cone|cones]] are globose to ovoid, 0.6–1.0 inches (1.5–2.5&nbsp;cm.) in diameter with 16–28 scales, arranged in opposite pairs in four rows, each pair at right angles to the adjacent pair; they mature in about 8–9 months after pollination.{{citation needed|date=April 2024}}

''Metasequoia'' has experienced morphological stasis for the past 65 million years: the modern ''[[Metasequoia glyptostroboides]]'' appears identical to its late [[Cretaceous]] ancestors.<ref>{{cite book |author=Ben A. LePage, Hong Yang & Midori Matsumoto |year=2005 |title=The evolution and biogeographic history of ''Metasequoia'' |pages=3–115}} In [[#LWY|LePage ''et al'' (2005)]].</ref>

== History ==
[[File:Metasequoia branchlet 03.jpg|thumb|right|upright|[[Eocene]] ([[Ypresian]]) age ''[[Metasequoia occidentalis|M.&nbsp;occidentalis]]'' branchlet]]
The fossil of this genus was discovered by [[Shigeru Miki]] in 1939. In 1941, Miki published the description of the fossil plant which he gave the name "Metasequoia". In the winter of the same year, a Chinese botanist Toh Gan (干铎) discovered an unusual big tree in Modaoxi (磨刀溪; presently, Moudao (谋道), in [[Lichuan City|Lichuan County]], Hubei).<ref name="langlois2005">{{cite book |author=Langlois |first=Gaytha A. |url=https://books.google.com/books?id=JfiWU-1GSqEC&pg=PA369 |title=A conservation plan for ''Metasequoia'' in China |year=2005 |isbn=9781402026317 |pages=367–418|publisher=Springer }} In [[Metasequoia#LWY|LePage ''et al'' (2005)]].</ref> The locals called this tree shui-sha (水桫). Because it was winter, the tree already lost all its leaves, so no specimens were collected by Mr. Gan. In 1942, another botanist, Mr. Zhan Wang (王战) visited Modaoxi and collected living specimens. Mr. Wang believed this tree belonged to a known species ''[[Glyptostrobus pensilis]]'' (水松) and filed the specimens away. In 1945, Mr. Wang showed the specimens to botanist [[Wan Chun Cheng]] (郑万钧). Mr. Cheng determined that the tree did not belong to ''[[Glyptostrobus pensilis]]'', but was a new species. Mr. Cheng then sent a specimen to prominent botanist [[Hu Xiansu]], the director of [[Fan Memorial Institute of Biology]]. Hu, despite the chaos of [[Second Sino-Japanese War|war between China and Japan]], was still keeping track of international botanic literature. Hu recognized the living specimen was of the same genus of Miki's fossil genus <nowiki>''</nowiki>''Metasequoia''<nowiki>''</nowiki>. After more study, Hu and Cheng published the new species ''[[Metasequoia glyptostroboides]]'' (Hu et Cheng) in May 1948 in the Bulletin of Fan Memorial Institute of Biology. The discovery of a "living fossil" instantly attracted attention from botanists around the world. It was widely regarded as "the greatest discovery of botany in 20th century". In 1948, the [[Arnold Arboretum]] of [[Harvard University]], through the help of Hu and Cheng, funded an expedition by Chinese collectors to collect seeds. Soon after, seeds were distributed to various universities and arboreta worldwide for growth trials.

Presently, a number of natural ''Metasequoia'' populations exist in the hills and wetlands of Hubei's Lichuan County. Most of them are small, with fewer than 30 trees each; however, the largest of them, in Xiaohe Valley, is estimated to consist of around 5,400 trees.<ref name=langlois2005/> A few trees are also said to exist in neighboring [[Hunan]] Province.<ref name=langlois2005/>

== ''Metasequoia'' in gardens, parks and streets ==
[[File:Metasequoia glyptostroboides mature habit.jpg|thumb|alt=Mature tree in autumn, with browning foliage|Mature tree in autumn]]
Dawn redwoods are fast-growing trees. They sometimes grow too large in smaller gardens under favorable conditions, but they can be a good choice for a wide range of larger gardens and parks. Although they live in wet sites in their native habitat they will also tolerate dry soils.<ref>{{cite book |title=Urban Forestry Practice, Forestry Commission Handbook 5 |year=1989 |editor=Hibberd |editor-first=B. G. |page=61}} In [[Metasequoia#BGH|Hibberd (1989)]].</ref> Unlike most conifers, their deciduous habit means they do not cast much shade in winter. They are grown as street trees in London and elsewhere.

[[Strawberry Fields (memorial)|Strawberry Fields]] is a landscaped section in New York City's Central Park dedicated to Beatle John Lennon. At the northern end of the lawns are three dawn redwood trees.{{citation needed|date=August 2016}} There are several other dawn redwood trees in New York City, including one in the [[Liz Christy Garden]], planted by Liz Christy herself in the 1970s, and a grove in the [[Brooklyn Botanical Garden]].<ref>{{Cite web |last=Young |first=Michelle |date=2017-06-05 |title=There's a Redwood Tree on Houston Street in NYC |url=https://untappedcities.com/2017/06/05/theres-a-redwood-tree-on-houston-street-in-nyc/ |access-date=2022-10-22 |website=Untapped New York |language=en-US}}</ref>

==References==
{{Reflist|32em}}

==Further reading==
{{Refbegin}}
* {{cite journal |author1=Zican He |author2=Jianqiang Li |author3=Qing Cai |author4=Xiaodong Li |author5=Hongwen Huang |year=2004 |title=Cytogenetic studies on ''Metasequoia glyptostroboides'', a living fossil species |journal=[[Genetica]] |volume=122 |issue=3 |pages=269–276 |pmid=15609550 |doi=10.1007/s10709-004-0926-x|s2cid=19447950 }}
* Proceedings of the Second International Symposium on ''Metasequoia'' and Associated Plants, August 6–10, 2006, Metasequoia: Back from the Brink? An Update. Edited by Hong Yang and Leo J. Hickey. Bulletin of the [[Peabody Museum of Natural History]], Volume 48, Issue 2 31 October 2007, pp.&nbsp;179–426. [http://www.peabody.yale.edu/scipubs/abstracts/abs_b48-2.html]
* The Reports of the Third International Metasequoia Symposium, August 3 to 8, 2010, Osaka, Japan [http://www.biology.tohoku.ac.jp/garden/meta/meta-reports.html]
* {{cite journal |author=[[A. Hope Jahren]] & Leonel Silveira Lobo Sternberg |year=2003 |title=Humidity estimate for the middle Eocene Arctic rain forest |journal=[[Geology (journal)|Geology]] |volume=31 |issue=5 |pages=463–466 |url=http://penguin.bio.miami.edu/leo/PDF%20articles/Jahren&Sternberg2003.pdf |archive-url=https://wayback.archive-it.org/all/20070927095758/http://penguin.bio.miami.edu/leo/PDF%20articles/Jahren&Sternberg2003.pdf |url-status=dead |archive-date=2007-09-27 |doi=10.1130/0091-7613(2003)031<0463:HEFTME>2.0.CO;2 |access-date=2019-05-29 |bibcode=2003Geo....31..463J }}
* {{cite journal |author1=Christopher J. Williams |author2=Ben A. LePage |author3=David R. Vann |author4=Takeshi Tange |author5=Hiroyuki Ikeda |author6=Makoto Ando |author7=Tomoko Kusakabe |author8=Hayato Tsuzuki |author9=Tatsuo Sweda |year=2003 |title=Structure, allometry, and biomass of plantation ''Metasequoia glyptostroboides'' in Japan |journal=[[Forest Ecology and Management]] |volume=180 |issue=1–3 |pages=287–301 |url=http://edisk.fandm.edu/chris.williams/pubs/williams_etal_2003.pdf |archive-url=https://web.archive.org/web/20080411035224/http://edisk.fandm.edu/chris.williams/pubs/williams_etal_2003.pdf |url-status=dead |archive-date=2008-04-11 |doi=10.1016/S0378-1127(02)00567-4 |bibcode=2003ForEM.180..287W }}
* {{cite book |editor1=Ben A. LePage |editor2=Christopher James Williams |editor3=Hong Yang |publisher=[[Springer Science+Business Media|Springer]] |year=2005 |isbn=1-4020-2631-5 |title=The Geobiology and Ecology of ''Metasequoia'' |volume=22 |series=Topics in geobiology |url=https://books.google.com/books?id=JfiWU-1GSqEC |location=[[Dordrecht]], the Netherlands |ref=LWY}}
* {{cite book |editor=B.G. Hibberd |publisher=[[Her Majesty's Stationery Office]] |year=1989 |isbn=0-11-710273-3 |title=Urban Forestry Practice, Forestry Commission Handbook 5 |url=http://forestry.oxfordjournals.org/content/63/2/218.full.pdf|location=[[London]]|ref=BGH}}{{dead link|date=May 2021|bot=medic}}{{cbignore|bot=medic}}
{{Refend}}

==External links==
{{Sister project links|display=''Metasequoia''|auto=1}}
* [https://web.archive.org/web/20070811045335/http://www.metasequoia.org/ The metasequoia organisation]
* [http://www.redwoodworld.co.uk Giant redwoods in the U.K.]
* {{ITIS |id = 505864 |taxon =''Metasequoia glyptostroboides''}}
* {{cite web |author=D.A. Hänks |title=Crescent Ridge Dawn Redwoods Preserve |url=http://www.dawnredwood.org/}}
* {{aut|Hu, H. H.}} & {{aut|Cheng, W. C.}} 1948. ''Bulletin of the Fan Memorial Institute of Biology'', new series 1: 154.
* {{WCSP|2017|Feb.|23}}

{{Acrogymnospermae classification}}
{{Taxonbar|from=Q1825748}}
{{Authority control}}

[[Category:Metasequoia| ]]
[[Category:Trees of China]]
[[Category:Endemic flora of China]]
[[Category:Extant Maastrichtian first appearances]]
[[Category:Maastrichtian genus first appearances]]
[[Category:Conifer genera]]
[[Category:Deciduous conifers]]
[[Category:Taxa named by Hu Xiansu]]