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Cephalotaxus

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Cephalotaxus
Temporal range: Eocene–Recent
Cephalotaxus harringtonii
Scientific classification Edit this classification
Kingdom: Plantae
Clade: Tracheophytes
Clade: Gymnospermae
Division: Pinophyta
Class: Pinopsida
Order: Cupressales
Family: Taxaceae
Genus: Cephalotaxus
Siebold & Zucc. ex Endl.
Type species
Cephalotaxus pedunculata
Species

Cephalotaxus, commonly called plum yew or cowtail pine, is a genus of conifers comprising 11 species, either considered the only member of the family Cephalotaxaceae, or in the Taxaceae when that family is considered in a broad sense.[1][2] The genus is endemic to eastern Asia, though fossil evidence shows it had a wider Northern Hemisphere distribution in the past.[1] The species are evergreen shrubs and small trees reaching 1.0–10 metres (3–33 ft) (rarely to 20 metres (66 ft)) tall.

Description

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The leaves are spirally arranged on the shoots, but twisted at the base to lie in two flat ranks (except on erect leading shoots); they are linear, 4–12 centimetres (1+1⁄2–4+3⁄4 in) long and 3–4 millimetres (1⁄8–5⁄32 in) broad, soft in texture, with a blunt tip; this helps distinguish them from the related genus Torreya, which has spine-tipped leaves.[2]

The species can be either monoecious or dioecious; when monoecious, the male and female cones are often on different branches. The male (pollen) cones are 5–8 millimetres (13⁄64–5⁄16 in) long, grouped in lines along the underside of a shoot. The female (seed) cones are single or grouped two to 15 together on short stems; minute at first, they mature in about 18 months to a drupe-like structure with the single large nut-like seed 1.5–4 centimetres (5⁄8–1+5⁄8 in) long surrounded by a fleshy covering, green to purple at full maturity. Natural dispersal is thought to be aided by squirrels which bury the seeds for a winter food source; any seeds left uneaten are then able to germinate.[2]

Phytochemistry

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Cephalotaxus species produce cephalotaxine, an alkaloid. Parry et al 1980 provides evidence that cephalotaxine is a phenylethylisoquinoline. However, they also find this genus to be unable to incorporate cinnamic acid into cephalotaxine, and incorporation of cinnamic acid is usually a step in phenylethylisoquinoline syntheses, throwing the phenylethylisoquinoline theory in to question.[3]

Phylogeny

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Molecular studies place Cephalotaxus as the most basal member of the Taxaceae, having a very ancient divergence from them during the late Triassic.[4] Historically, it was placed as the only member of the family Cephalotaxaceae, due to strong morphological differences from other members of Taxaceae,[5] but major authorities consider the family synonymous with Taxaceae.[6][7]

Extant species

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The taxonomy of Cephalotaxus is difficult, because the species have been defined using characteristics that intergrade with each other, such as the length and shape of needles, bark, and stomatal band color. Cephalotaxus species have often been separated geographically rather than morphologically.[8]

Phylogeny of Cephalotaxus[9][10]
Cephalotaxus

C. oliveri Masters

C. harringtonii (Knight ex Forbes) Koch

C. hainanensis Li

C. mannii Hooker

C. sinensis (Rehder & Wilson) Li

C. drupacea Siebold & Zuccarini

C. nana Nakai

C. griffithii Hooker

C. lanceolata Feng ex Cheng, Fu & Cheng

C. fortunei Hooker

Fossil record

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Cephalotaxus bonseri
Latah Formation, Miocene

The oldest fossils of Cephalotaxus are known from the Eocene of Heilongjiang in northeast China and the Messel Pit of Germany. The youngest fossils of Cephalotaxus in Europe date to the Pliocene, and remains are also known from the Miocene of western North America.[11][12]

References

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  1. ^ a b Tripp, Kim E. (1995). "Cephalotaxus: the plum yews". Arnoldia. 55 (1): 25–39. doi:10.5962/p.251135.
  2. ^ a b c Christopher J. Earle (2011). "Cephalotaxus". The Gymnosperm Database. Archived from the original on 30 March 2012. Retrieved 31 March 2012.
  3. ^ Abdelkafi, Hajer; Nay, Bastien (2012-08-01). "Natural products from Cephalotaxus sp.: chemical diversity and synthetic aspects". Natural Product Reports. 29 (8). Royal Society of Chemistry (RSC): 845–869. doi:10.1039/C2NP20037F. ISSN 1460-4752. PMID 22714632.
  4. ^ 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 (August 2021). "Gene duplications and phylogenomic conflict underlie major pulses of phenotypic evolution in gymnosperms". Nature Plants. 7 (8): 1015–1025. doi:10.1038/s41477-021-00964-4. ISSN 2055-0278. PMID 34282286. S2CID 236141481.
  5. ^ Ji, Yunheng; Liu, Changkun; Landis, Jacob B; Deng, Min; Chen, Jiahui (2021-04-17). "Plastome phylogenomics of Cephalotaxus (Cephalotaxaceae) and allied genera". Annals of Botany. 127 (5): 697–708. doi:10.1093/aob/mcaa201. ISSN 0305-7364. PMC 8052924. PMID 33252661.
  6. ^ "Cephalotaxus Siebold & Zucc. ex Endl. | Plants of the World Online | Kew Science". Plants of the World Online. Retrieved 2023-03-21.
  7. ^ "Gymnosperms - The Gymnosperm Database". www.conifers.org. Retrieved 2023-03-21.
  8. ^ Lang, XUE-Dong; Su, Jian-Rong; Lu, SHU-Gang; Zhang, ZHI-JUN (2013). "A taxonomic revision of the genus Cephalotaxus (Taxaceae)". Phytotaxa. 84. doi:10.11646/phytotaxa.84.1.1.
  9. ^ 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; Smith, Stephen A.; Yi, Ting-Shuang; et al. (2021). "Gene duplications and phylogenomic conflict underlie major pulses of phenotypic evolution in gymnosperms". Nature Plants. 7 (8): 1015–1025. bioRxiv 10.1101/2021.03.13.435279. doi:10.1038/s41477-021-00964-4. PMID 34282286. S2CID 232282918.
  10. ^ Stull, Gregory W.; et al. (2021). "main.dated.supermatrix.tree.T9.tre". Figshare. doi:10.6084/m9.figshare.14547354.v1. {{cite journal}}: Cite journal requires |journal= (help)
  11. ^ Manchester, Steven R.; Chen, Zhi-Duan; Lu, An-Ming; Uemura, Kazuhiko (January 2009). "Eastern Asian endemic seed plant genera and their paleogeographic history throughout the Northern Hemisphere". Journal of Systematics and Evolution. 47 (1): 1–42. doi:10.1111/j.1759-6831.2009.00001.x.
  12. ^ "Cephalotaxus". The International Fossil Plant Names Index. Retrieved October 1, 2023.
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