Taxaceae
| Taxaceae Temporal range:(possible Late Triassic records)
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|---|---|
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| Foliage and mature arils of a yew plant | |
Scientific classification
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| Kingdom: | Plantae |
| Clade: | Tracheophytes |
| Clade: | Gymnospermae |
| Division: | Pinophyta |
| Class: | Pinopsida |
| Order: | Cupressales |
| Family: | Taxaceae S.F.Gray |
| Genera | |
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| Synonyms | |
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Taxaceae(/tækˈseɪsi.iː,-ˌaɪ/), commonly called theyew family,is aconiferousfamilywhich includes sixextantand two extinct genera, and about 30 species ofplants,or in older interpretations three genera and 7 to 12 species.
Description
[edit]They are many-branched, smalltreesandshrubs.The leaves areevergreen,spirally arranged, often twisted at the base to appear 2-ranked. They are linear to lanceolate, and have pale green or white stomatal bands on the undersides.[1]
The plants aredioecious,or rarelymonoecious.The catkin like maleconesare 2–5 millimetres (0.079–0.197 in) long, and shedpollenin the early spring. They are sometimes externally only slightly differentiated from the branches. The fertile bracts have 2-8 pollen sacs.[1][2]
The female 'cones' are highly reduced.[1]Only the upper or uppermost bracts are fertile and bear one or rarely two seeds.[2]The ovule usually exceeds the scale, although ovules are sometimes rarely enclosed by it. They may be found on the ends of branches or on the branches. They may grow singly or in tufts or clumps.[2]
As the seed matures, a fleshyarilpartly encloses it. The developmental origin of the aril is unclear, but it may represent a fused pair of swollen leaves.[1]The mature aril is brightly coloured, soft, juicy and sweet, and is eaten bybirdswhich then disperse the hard seed undamaged in their droppings. However, the seeds are highly poisonous to humans, containing the poisonstaxineandtaxol.[3]
Distribution
[edit]Species are mostly found in the tropics and temperate zones in the northern temperate. There are only a few species in the southern hemisphere.[2]
Classification
[edit]Taxaceae is now generally included with all other conifers in the orderPinales,asDNAanalysis has shown that the yews are phylogenetically nested in the Pinales,[4]a conclusion supported bymicromorphologystudies.[5]Formerly they were often treated as distinct from other conifers by placing them in a separate orderTaxales.Ernest Henry Wilsonreferred to Taxaceae as "taxads" in his 1916 book.[6]Taxaceae is thought to be the sister group toCupressaceae,from which it diverged during the early-midTriassic.The clade comprising both is sister toSciadopityaceae,which diverged from them during the early-midPermian.[7]The oldest confirmed member of Taxaceae isPalaeotaxus redivivafrom the earliestJurassic(Hettangian) of Sweden. Fossils belonging to the living genusAmentotaxusfrom the Middle Jurassic of China indicate that Taxaceae had already substantially diversified during the Jurassic.[8]
The broadly defined Taxaceae (includingCephalotaxus) comprises six extant genera and about 30 species overall.Cephalotaxusis now included in Taxaceae, rather than being recognized as the core of its own family,Cephalotaxaceae.Phylogenetic evidence strongly supports a very close relationship betweenCephalotaxusand other members of Taxaceae,[9][10][11]and morphological differences between them are not substantial. Previous recognition of two distinct families, Taxaceae and Cephalotaxaceae (e.g.,[12]), was based on relatively minor morphological details: Taxaceae (excludingCephalotaxus) has smaller mature seeds growing to 5–8 millimetres (0.20–0.31 in) in 6–8 months, that are not fully enclosed by the aril; in contrast,Cephalotaxusseeds have a longer maturation period (from 18–20 months), and larger mature seeds (12–40 millimetres (0.47–1.57 in)) fully enclosed by the aril. However, there are also very clear morphological connections betweenCephalotaxusand other members of Taxaceae,[13][14]and considered in tandem with the phylogenetic evidence, there is no compelling need to recognizeCephalotaxus(or other genera in Taxaceae) as a distinct family,.[9][10]
Phylogeny
[edit]Phylogeny of Taxaceae.[15][16]
AmentotaxusPilg.– Catkin-yew
- Amentotaxus argotaenia- Catkin yew
- Amentotaxus assamica- Assam catkin yew
- Amentotaxus formosana- Taiwan catkin yew
- Amentotaxus poilanei- Poilane's catkin yew
- Amentotaxus yunnanensis- Yunnan catkin yew
AustrotaxusCompton– New Caledonia yew
- Austrotaxus spicata- New Caledonia yew or southern yew
CephalotaxusSiebold & Zucc. ex Endl.– Plum yew
- Cephalotaxus fortunei- Chinese plum-yew
- Cephalotaxus griffithii- Griffith's plum yew
- Cephalotaxus hainanensis- Hainan plum-yew
- Cephalotaxus harringtonii- Korean plum yew, Japanese plum-yew
- Cephalotaxus koreana- Korean plum yew
- Cephalotaxus lanceolata- Gongshan plum yew
- Cephalotaxus latifolia- Broad-leaved plum yew
- Cephalotaxus mannii- Mann's yew plum
- Cephalotaxus oliveri- Oliver's plum yew
- Cephalotaxus sinensis- Chinese plum yew
- Cephalotaxus wilsoniana- Taiwan plum yew, Taiwan cow's-tail pine, or Wilson plum yew
PseudotaxusW.C.Cheng– White-berry yew
- Pseudotaxus chienii- the whiteberry yew
TaxusL.– Common yew
- Taxus baccataEuropean yew
- Taxus biternataDelicate branch yew
- Taxus brevifoliaPacific yew, western yew
- Taxus caespitosaCaespitosa yew
- Taxus calcicolaAsian limestone yew
- Taxus canadensisCanada yew
- Taxus celebicaCelebes yew
- Taxus chinensisChina yew
- Taxus contortaWest Himalayan yew
- Taxus cuspidataRigid branch yew, Japanese yew
- Taxus fastigiataIrish yew
- Taxus floridanaFlorida yew
- Taxus floriniiFlorin yew
- Taxus globosaMesoamerican yew
- Taxus kingstoniiKingston yew
- Taxus maireiMaire yew
- Taxus obscuraObscure yew
- Taxus ocreataScaly yew
- Taxus phytoniiPhyton yew
- Taxus recurvataEnglish yew
- Taxus rehderianaRehder yew
- Taxus scutataScutaceous yew
- Taxus suffnessiiSuffness yew
- Taxus sumatranaSumatera yew
- Taxus umbraculiferaUmbrelliform yew
- Taxus wallichianaWallich yew, East Himalayan yew
TorreyaArn.– Nutmeg yew
- Torreya californica- California torreya
- Torreya fargesii- Farges nutmeg tree
- Torreya grandis- Chinese nutmeg yew
- Torreya jackii- Jack's nutmeg tree, longleaf torreya etc
- Torreya nucifera- kaya, Japanese torreya, or Japanese nutmeg-yew
- Torreya taxifolia- Gopher wood
- †Torreya clarnensis[17]
Footnotes
[edit]
- ^abcdDörken, Veit Martin; Nimsch, Hubertus; Rudall, Paula J (2018-08-22)."Origin of the Taxaceae aril: evolutionary implications of seed-cone teratologies in Pseudotaxus chienii".Annals of Botany.123(1). Oxford University Press (OUP): 133–143.doi:10.1093/aob/mcy150.ISSN0305-7364.PMC6344100.PMID30137225.
- ^abcdPhillips, Edwin Percy (1951).The genera of South African flowering plants.South Africa: Government Printer.
- ^Yew Poisoning: MedLine Plus Medical Encyclopedia
- ^Chase, M. W.; Soltis, D. E.; et al. (1993)."Phylogenetics of Seed Plants: An Analysis of Nucleotide Sequences from the Plastid Gene rbcL"(PDF).Annals of the Missouri Botanical Garden.80(3). JSTOR: 528.doi:10.2307/2399846.hdl:1969.1/179875.ISSN0026-6493.JSTOR2399846.
- ^Anderson, E.; Owens, J.N. (2003)."Analyzing the Reproductive Biology of Taxus: Should It be Included in Coniferales?".Acta Horticulturae(615). International Society for Horticultural Science (ISHS): 233–234.doi:10.17660/actahortic.2003.615.22.ISSN0567-7572.Archived fromthe originalon 2022-11-26.Retrieved2021-06-22.
- ^Wilson, Ernest Henry (1916).The conifers and taxads of Japan. Issued December 30, 1916.Cambridge: University Press.doi:10.5962/bhl.title.17457.
- ^Stull, Gregory W.; Qu, Xiao-Jian; Parins-Fukuchi, Caroline; Yang, Ying-Ying; Yang, Jun-Bo; Yang, Zhi-Yun; Hu, Yi; Ma, Hong; Soltis, Pamela S.; Soltis, Douglas E.; Li, De-Zhu (July 19, 2021)."Gene duplications and phylogenomic conflict underlie major pulses of phenotypic evolution in gymnosperms".Nature Plants.7(8): 1015–1025.Bibcode:2021NatPl...7.1015S.doi:10.1038/s41477-021-00964-4.ISSN2055-0278.PMID34282286.S2CID236141481.
- ^Dong, Chong; Shi, Gongle; Herrera, Fabiany; Wang, Yongdong; Herendeen, Patrick S; Crane, Peter R (2020-06-18)."Middle–Late Jurassic fossils from northeastern China reveal morphological stasis in the catkin-yew".National Science Review.7(11): 1765–1767.doi:10.1093/nsr/nwaa138.ISSN2095-5138.PMC8288717.PMID34691509.
- ^abQuinn, C. J.; Price, R. A.; Gadek, P. A. (2002). "Familial Concepts and Relationships in the Conifer Based on rbcL and matK Sequence Comparisons".Kew Bulletin.57(3). JSTOR: 513.Bibcode:2002KewBu..57..513Q.doi:10.2307/4110984.ISSN0075-5974.JSTOR4110984.S2CID83816639.
- ^abRai, Hardeep S.; Reeves, Patrick A.; Peakall, Rod; Olmstead, Richard G.; Graham, Sean W. (2008). "Inference of higher-order conifer relationships from a multi-locus plastid data set".Botany.86(7). Canadian Science Publishing: 658–669.doi:10.1139/b08-062.ISSN1916-2790.S2CID14007221.
- ^One Thousand Plant Transcriptomes Initiative (2019)."One thousand plant transcriptomes and the phylogenomics of green plants".Nature.574(7780). Springer Science and Business Media LLC: 679–685.doi:10.1038/s41586-019-1693-2.ISSN0028-0836.PMC6872490.PMID31645766.
- ^Hart, Jeffrey A. (1987)."A cladistic analysis of conifers: preliminary results".Journal of the Arnold Arboretum.68(3): 269–307.doi:10.5962/p.185944.ISSN0004-2625.JSTOR43782212.S2CID88860959.
- ^Doyle, James A. (1998). "Phylogeny of Vascular Plants".Annual Review of Ecology and Systematics.29(1). Annual Reviews: 567–599.doi:10.1146/annurev.ecolsys.29.1.567.ISSN0066-4162.S2CID85631751.
- ^Stützel, Thomas; Röwekamp, Iris (1999)."Female reproductive structures in Taxales".Flora.194(2). Elsevier BV: 145–157.Bibcode:1999FMDFE.194..145S.doi:10.1016/s0367-2530(17)30893-9.ISSN0367-2530.
- ^Leslie, Andrew B.; Beaulieu, Jeremy; Holman, Garth; Campbell, Christopher S.; Mei, Wenbin; Raubeson, Linda R.; Mathews, Sarah; et al. (2018)."An overview of extant conifer evolution from the perspective of the fossil record".American Journal of Botany.105(9): 1531–1544.doi:10.1002/ajb2.1143.PMID30157290.
- ^Leslie, Andrew B.; et al. (2018)."ajb21143-sup-0004-AppendixS4"(PDF).American Journal of Botany.105(9): 1531–1544.doi:10.1002/ajb2.1143.PMID30157290.S2CID52120430.
- ^Manchester, S.R. (1994)."Fruits and Seeds of the Middle Eocene Nut Beds Flora, Clarno Formation, Oregon".Palaeontographica Americana.58:30–31.
