Sequoioideae, commonly referred to as redwoods, is a

subfamily In biological classification, a subfamily (Latin: ', plural ') is an auxiliary (intermediate) taxonomic rank, next below family but more inclusive than genus. Standard nomenclature rules end botanical subfamily names with "-oideae", and zo ...

coniferous Conifers () are a group of conifer cone, cone-bearing Spermatophyte, seed plants, a subset of gymnosperms. Scientifically, they make up the phylum, division Pinophyta (), also known as Coniferophyta () or Coniferae. The division contains a sin ...

trees within the

family Family (from ) is a Social group, group of people related either by consanguinity (by recognized birth) or Affinity (law), affinity (by marriage or other relationship). It forms the basis for social order. Ideally, families offer predictabili ...

Cupressaceae Cupressaceae or the cypress family is a family of conifers. The family includes 27–30 genera (17 monotypic), which include the junipers and redwoods, with about 130–140 species in total. They are monoecious, subdioecious or (rarely) dioecio ...

, that range in the

northern hemisphere The Northern Hemisphere is the half of Earth that is north of the equator. For other planets in the Solar System, north is defined by humans as being in the same celestial sphere, celestial hemisphere relative to the invariable plane of the Solar ...

. It includes the largest and tallest trees in the world. The trees in the

are amongst the most notable trees in the world and are common

ornamental Ornamental may refer to: *Ornamental grass, a type of grass grown as a decoration *Ornamental iron, mild steel that has been formed into decorative shapes, similar to wrought iron work *Ornamental plant, a plant that is grown for its ornamental qua ...

trees. The

reached its peak of diversity during the early

Cenozoic The Cenozoic Era ( ; ) is Earth's current geological era, representing the last 66million years of Earth's history. It is characterized by the dominance of mammals, insects, birds and angiosperms (flowering plants). It is the latest of three g ...

Description

The three redwood subfamily

genera Genus (; : genera ) is a taxonomic rank above species and below family as used in the biological classification of living and fossil organisms as well as viruses. In binomial nomenclature, the genus name forms the first part of the binomial s ...

are '' Sequoia'' from coastal

California California () is a U.S. state, state in the Western United States that lies on the West Coast of the United States, Pacific Coast. It borders Oregon to the north, Nevada and Arizona to the east, and shares Mexico–United States border, an ...

and

Oregon Oregon ( , ) is a U.S. state, state in the Pacific Northwest region of the United States. It is a part of the Western U.S., with the Columbia River delineating much of Oregon's northern boundary with Washington (state), Washington, while t ...

, ''

Sequoiadendron ''Sequoiadendron'' is a genus of evergreen trees, with three species, only one of which survives to the present: * ''Sequoiadendron giganteum'', extant species, extant, commonly known as wellingtonia, giant redwood and giant sequoia, growing nat ...

'' from California's

Sierra Nevada The Sierra Nevada ( ) is a mountain range in the Western United States, between the Central Valley of California and the Great Basin. The vast majority of the range lies in the state of California, although the Carson Range spur lies primari ...

, and ''

Metasequoia ''Metasequoia'', or dawn redwood, is a genus of fast-growing coniferous trees. It contains one extant (living) species, ''Metasequoia glyptostroboides'', which is one of three extant species of conifers known as redwoods in the world. ''Metaseq ...

'' in

China China, officially the People's Republic of China (PRC), is a country in East Asia. With population of China, a population exceeding 1.4 billion, it is the list of countries by population (United Nations), second-most populous country after ...

. The redwood subfamily contains the largest and tallest trees in the world. These trees can live for thousands of years. Threats include logging, fire suppression, and

burl A burl (American English) or burr (British English) is a tree growth in which the grain has grown in a deformed manner. It is commonly found in the form of a rounded outgrowth on a tree trunk or branch that is filled with small knots from d ...

poaching. Only two of the genera, ''Sequoia'' and ''Sequoiadendron'', are known for massive trees. Trees of ''

'', from the single living species ''

Metasequoia glyptostroboides ''Metasequoia glyptostroboides'', the dawn redwood, is a fast-growing, endangered deciduous pinophyta, conifer. It is the sole living species of the genus ''Metasequoia'', one of three genera in the subfamily Sequoioideae of the family (botany), ...

'', are deciduous, grow much smaller (although are still large compared to most other trees) and can live in colder climates.

Taxonomy and evolution

Multiple studies of both morphological and molecular characters have strongly supported the assertion that the Sequoioideae are

monophyletic In biological cladistics for the classification of organisms, monophyly is the condition of a taxonomic grouping being a clade – that is, a grouping of organisms which meets these criteria: # the grouping contains its own most recent co ...

. Most modern

phylogenies A phylogenetic tree or phylogeny is a graphical representation which shows the evolutionary history between a set of species or taxa during a specific time.Felsenstein J. (2004). ''Inferring Phylogenies'' Sinauer Associates: Sunderland, MA. In o ...

place ''Sequoia'' as sister to ''Sequoiadendron'' and ''Metasequoia '' as the out-group. However, Yang ''et al.'' went on to investigate the origin of a peculiar genetic component in Sequoioideae, the

polyploidy Polyploidy is a condition in which the cells of an organism have more than two paired sets of ( homologous) chromosomes. Most species whose cells have nuclei (eukaryotes) are diploid, meaning they have two complete sets of chromosomes, one fro ...

of ''Sequoia''—and generated a notable exception that calls into question the specifics of this relative consensus.

Cladistic tree

A 2006 paper based on non-molecular evidence suggested the following relationship among extant species: A 2021 study using molecular evidence found the same relationships among Sequoioideae species, but found Sequoioideae to be the sister group to the Athrotaxidoideae (a superfamily presently known only from

Tasmania Tasmania (; palawa kani: ''Lutruwita'') is an island States and territories of Australia, state of Australia. It is located to the south of the Mainland Australia, Australian mainland, and is separated from it by the Bass Strait. The sta ...

) rather than to

Taxodioideae Taxodioideae is a subfamily in Cupressaceae Cupressaceae or the cypress family is a family of conifers. The family includes 27–30 genera (17 monotypic), which include the junipers and redwoods, with about 130–140 species in total. They ar ...

. Sequoioideae and Athrotaxidoideae are thought to have diverged from each other during the

Jurassic The Jurassic ( ) is a Geological period, geologic period and System (stratigraphy), stratigraphic system that spanned from the end of the Triassic Period million years ago (Mya) to the beginning of the Cretaceous Period, approximately 143.1 Mya. ...

Possible reticulate evolution in Sequoioideae

Reticulate evolution Reticulate evolution, or network evolution is the origination of a lineage through the partial merging of two ancestor lineages, leading to relationships better described by a phylogenetic network than a bifurcating tree. Reticulate patterns can ...

refers to the origination of a taxon through the merging of ancestor lineages.

Polyploidy Polyploidy is a condition in which the cells of an organism have more than two paired sets of ( homologous) chromosomes. Most species whose cells have nuclei (eukaryotes) are diploid, meaning they have two complete sets of chromosomes, one fro ...

has come to be understood as quite common in plants—with estimates ranging from 47% to 100% of flowering plants and extant

ferns The ferns (Polypodiopsida or Polypodiophyta) are a group of vascular plants (plants with xylem and phloem) that reproduce via spores and have neither seeds nor flowers. They differ from mosses by being vascular, i.e., having specialized tissue ...

having derived from ancient polyploidy. Within the gymnosperms however it is quite rare. ''Sequoia sempervirens'' is

hexaploid Polyploidy is a condition in which the cells of an organism have more than two paired sets of ( homologous) chromosomes. Most species whose cells have nuclei (eukaryotes) are diploid, meaning they have two complete sets of chromosomes, one fro ...

(2n= 6x= 66). To investigate the origins of this polyploidy Yang et al. used two single copy

nuclear gene A nuclear gene is a gene whose DNA sequence is located within the cell nucleus of a eukaryotic organism. These genes are distinguished from extranuclear genes, such as those found in the genomes of mitochondria and chloroplasts, which reside ou ...

s, LFY and NLY, to generate

phylogenetic tree A phylogenetic tree or phylogeny is a graphical representation which shows the evolutionary history between a set of species or taxa during a specific time.Felsenstein J. (2004). ''Inferring Phylogenies'' Sinauer Associates: Sunderland, MA. In ...

s. Other researchers have had success with these genes in similar studies on different taxa. Several hypotheses have been proposed to explain the origin of ''Sequoia's ''polyploidy:

allopolyploidy Polyploidy is a condition in which the cells of an organism have more than two paired sets of ( homologous) chromosomes. Most species whose cells have nuclei (eukaryotes) are diploid, meaning they have two complete sets of chromosomes, one from ...

hybrid Hybrid may refer to: Science * Hybrid (biology), an offspring resulting from cross-breeding ** Hybrid grape, grape varieties produced by cross-breeding two ''Vitis'' species ** Hybridity, the property of a hybrid plant which is a union of two diff ...

ization between ''Metasequoia'' and some probably extinct taxodiaceous plant; ''Metasequoia'' and ''Sequoiadendron,'' or ancestors of the two genera, as the parental species of ''Sequoia''; and autohexaploidy, autoallohexaploidy, or segmental allohexaploidy. Yang et al. found that ''Sequoia'' was clustered with ''Metasequoia'' in the tree generated using the LFY gene but with ''Sequoiadendron ''in the tree generated with the NLY gene. Further analysis strongly supported the hypothesis that ''Sequoia'' was the result of a hybridization event involving ''Metasequoia'' and ''Sequoiadendron''. Thus, Yang et al. hypothesize that the inconsistent relationships among ''Metasequoia'', ''Sequoia,'' and ''Sequoiadendron'' could be a sign of

reticulate evolution Reticulate evolution, or network evolution is the origination of a lineage through the partial merging of two ancestor lineages, leading to relationships better described by a phylogenetic network than a bifurcating tree. Reticulate patterns can ...

hybrid speciation Hybrid speciation is a form of speciation where hybridization between two different species leads to a new species, reproductively isolated from the parent species. Previously, reproductive isolation between two species and their parents was tho ...

(in which two species hybridize and give rise to a third) among the three genera. However, the long evolutionary history of the three genera (the earliest fossil remains being from the

) make resolving the specifics of when and how ''Sequoia'' originated once and for all a difficult matter—especially since it in part depends on an incomplete fossil record.

Extant species

*''

'' - Dawn redwood; south-central China. *''

Sequoiadendron giganteum ''Sequoiadendron giganteum'' (also known as the giant sequoia, giant redwood, Sierra redwood or Wellingtonia) is a species of coniferous tree, classified in the family Cupressaceae in the subfamily Sequoioideae. Giant sequoia specimens are the la ...

'' - Giant sequoia, Giant redwood; western slopes of the Sierra Nevadas; California. *''

Sequoia sempervirens ''Sequoia sempervirens'' ()''Sunset Western Garden Book,'' 1995: 606–607 is the sole living species of the genus ''Sequoia (genus), Sequoia'' in the cypress family Cupressaceae (formerly treated in Taxodiaceae). Common names include coast ...

'' - Coastal Redwood, California redwood;

Northern California Northern California (commonly shortened to NorCal) is a geocultural region that comprises the northern portion of the U.S. state of California, spanning the northernmost 48 of the state's List of counties in California, 58 counties. Northern Ca ...

coast and extreme Southern

Paleontology

Sequoioideae is an ancient

taxon In biology, a taxon (back-formation from ''taxonomy''; : taxa) is a group of one or more populations of an organism or organisms seen by taxonomists to form a unit. Although neither is required, a taxon is usually known by a particular name and ...

, with the oldest described Sequoioideae species, ''

Sequoia jeholensis ''Sequoia jeholensis'' was a species of redwood tree that existed during Jurassic and Cretaceous periods from 174.7-118.9 MYA. The earlier fossils come from the Middle to Late Jurassic in what is now Liaoning Province, China. Remains dated the Ear ...

'', recovered from

deposits.Ahuja M. R. and D. B. Neale. 2002
Origins of polyploidy in coast redwood (Sequoia sempervirens) and relationship of coast redwood (Sequoia sempervirens) to other genera of Taxodiaceae.
Silvae Genetica 51: 93–99. The fossil wood '' Medulloprotaxodioxylon'', reported from the late Triassic of China, resembles ''Sequoiadendron giganteum'' and may represent an ancestral form of the Sequoioideae; this supports the idea of a Late Triassic

Norian The Norian is a division of the Triassic geological period, Period. It has the rank of an age (geology), age (geochronology) or stage (stratigraphy), stage (chronostratigraphy). It lasted from ~227.3 to Mya (unit), million years ago. It was prec ...

origin for this subfamily. The fossil record shows a massive expansion of range in the

Cretaceous The Cretaceous ( ) is a geological period that lasted from about 143.1 to 66 mya (unit), million years ago (Mya). It is the third and final period of the Mesozoic Era (geology), Era, as well as the longest. At around 77.1 million years, it is the ...

and dominance of the

Arcto-Tertiary Geoflora The Arcto-Tertiary Geoflora is a hypothesized floral assemblage that once covered the Northern Hemisphere, from roughly the late Mesozoic to mid Cenozoic Eras. Origins First proposed by the paleobotanists J.S. Gardner and C. Ettinghausen in 1879 ...

, especially in northern latitudes. Genera of Sequoioideae were found in the

Arctic Circle The Arctic Circle is one of the two polar circles, and the northernmost of the five major circle of latitude, circles of latitude as shown on maps of Earth at about 66° 34' N. Its southern counterpart is the Antarctic Circle. The Arctic Circl ...

, Europe, North America, and throughout Asia and Japan. A general cooling trend beginning in the late

Eocene The Eocene ( ) is a geological epoch (geology), epoch that lasted from about 56 to 33.9 million years ago (Ma). It is the second epoch of the Paleogene Period (geology), Period in the modern Cenozoic Era (geology), Era. The name ''Eocene'' comes ...

and

Oligocene The Oligocene ( ) is a geologic epoch (geology), epoch of the Paleogene Geologic time scale, Period that extends from about 33.9 million to 23 million years before the present ( to ). As with other older geologic periods, the rock beds that defin ...

reduced the northern ranges of the Sequoioideae, as did subsequent ice ages. Evolutionary adaptations to ancient environments persist in all three species despite changing climate, distribution, and associated flora, especially the specific demands of their reproduction ecology that ultimately forced each of the species into refugial ranges where they could survive. The extinct genus ''

Austrosequoia ''Austrosequoia'' was a genus of redwood that existed from the Cretaceous to Oligocene in what is now Australia and New Zealand. Fossils are known from the Winton Formation, the Little Rapid River in Tasmania and the Tupuangi Formation. While t ...

'', known from the Late Cretaceous-Oligocene of the Southern Hemisphere, including Australia and New Zealand, has been suggested as a member of the subfamily.

Conservation

In 2024, it was estimated that there were about 500,000 redwoods in Britain, mostly brought as seeds and seedlings from the US in the

Victorian era In the history of the United Kingdom and the British Empire, the Victorian era was the reign of Queen Victoria, from 20 June 1837 until her death on 22 January 1901. Slightly different definitions are sometimes used. The era followed the ...

. The entire subfamily is

endangered An endangered species is a species that is very likely to become extinct in the near future, either worldwide or in a particular political jurisdiction. Endangered species may be at risk due to factors such as habitat loss, poaching, inv ...

. The

IUCN Red List The International Union for Conservation of Nature (IUCN) Red List of Threatened Species, also known as the IUCN Red List or Red Data Book, founded in 1964, is an inventory of the global conservation status and extinction risk of biological ...

Category & Criteria assesses ''Sequoia sempervirens'' as Endangered (A2acd), ''Sequoiadendron giganteum'' as Endangered (B2ab) and ''Metasequoia glyptostroboides'' as Endangered (B1ab). In 2024 it was reported that over a period of two years about one-fifth of all giant sequoias were destroyed in extreme wildfires in California.

References

Bibliography and links

* * * * * :de:Liste der dicksten Mammutbäume in Deutschland. List of Large Giant Redwoods in Germany * IUCN 2013. IUCN Red List of Threatened Species. Version 2013.2. Downloaded on 10 January 2014. * *

External links

* {{Authority control Plant subfamilies