| Xanthocyparis | |
|---|---|
 | |
Scientific classification | |
| Kingdom: | Plantae |
| Clade: | Tracheophytes |
| Clade: | Gymnospermae |
| Division: | Pinophyta |
| Class: | Pinopsida |
| Order: | Cupressales |
| Family: | Cupressaceae |
| Genus: | Xanthocyparis Farjon & T.H.Nguyên[3] |
| Species: | X. vietnamensis |
| Binomial name | |
| Xanthocyparis vietnamensis Farjon & T.H.Nguyên[2] | |
| Synonyms[2] | |
Species:
| |
Xanthocyparis is agenus ofcypresses in the familyCupressaceae. As of August 2021[update], it has only one species,Xanthocyparis vietnamensis,[3] native toVietnam and southeastChina.[2] It is commonly known as theVietnamese golden cypress. The Nootka cypress,Cupressus nootkatensis orCallitropsis nootkatensis, was also placed in the genus, but this has been rejected.
In 2002,Aljos Farjon and others described the new genusXanthocyparis to accommodate the new Vietnamese speciesX. vietnamensis and another species, the Nootka cypress, which had been formerly included in the genusChamaecyparis asC. nootkatensis.[4] This was based in part on the discovery thatC. nootkatensis was more closely related to the genusCupressus than toChamaecyparis.[5]
In 2004, Damon Little and others, while confirming the above relationship with further evidence, pointed out that as circumscribed by Farjonet al.,Xanthocyparis included the type species ofCallitropsis (Cupressus nootkatensis, a synonym ofChamaecyparis nootkatensis andXanthocyparis nootkatensis).[6]Callitropsis had been described byAnders Sandøe Ørsted in 1864, but this name had been overlooked by Farjon and most other authors; under the rules of theInternational Code of Botanical Nomenclature,Callitropsis as the earlier-published name hadnomenclatural priority overXanthocyparis if that genus includedCupressus nootkatensis. Littleet al. therefore recognizedXanthocyparis as a synonym ofCallitropsis. The nameXanthocyparis was proposed for conservation overCallitropsis,[7] a decision that was ratified at theInternational Botanical Congress in 2011.[8]
Littleet al. also presented evidence thatCupressus is paraphyletic with respect toJuniperus andXanthocyparis, with the North American species ofCupressus being more closely related toXanthocyparis than they are to theEuropean and AsianCupressus species.[6] These species were transferred toCallitropsis by Damon Little in 2006,[9] although this transfer was not universally accepted.[10] In 2009, most of the North American species previously included inCallitropsis were placed in a separate genus,Hesperocyparis.[11]
A 2021 molecular study foundXanthocyparis to besister to aclade comprisingHesperocyparis andCallitropsis, with the clade containing all three being sister to a clade comprisingJuniperus andCupressus sensu stricto.[12]
Xanthocyparis vietnamensis was originally described asendemic toVietnam, being native only to thekarst limestone mountains of theHà Giang Province in northern Vietnam.[13] It has since also been recorded inCao Bằng andTuyên Quang provinces in Vietnam, as well as southeast China (Guangxi).[2]
