Biology:Athrotaxis
Athrotaxis is a genus of two to three species (depending on taxonomic opinion) of conifers in the cypress family, Cupressaceae. The genus is endemic to western Tasmania, where they grow in high-elevation temperate rainforests.[1] They are also considered alpine plants.[2]
They are medium-sized evergreen trees, reaching 10–30 m (rarely 40 m) tall and 1-1.5 m trunk diameter. The leaves are scale-like, 3–14 mm long, are borne spirally on the shoots. The cones are globose to oval, 1–3 cm diameter, with 15-35 scales, each scale with 3-6 seeds; they are mature in 7–9 months after pollination, when they open to release the seeds. The male (pollen) cones are small, and shed their pollen in early spring.[1]
They are very susceptible to bush fires, and have declined markedly in abundance due to accidental and deliberate fires since the European colonisation of Tasmania.[1]
Classification
Taxonomy
Athrotaxis is the only living genus of the subfamily Athrotaxidoideae. A 2021 molecular study found the Athrotaxidoideae to be the sister group to the Sequoioideae, which contains famously massive species such as the coast redwood (Sequoia sempervirens) and giant sequoia (Sequoiadendron giganteum). This is despite both subfamilies' current distributions being on entirely different hemispheres. The study indicates that both taxa diverged during the mid to late Jurassic.[3] The oldest fossil of the genus is known from the Early Cretaceous (Aptian) of Santa Cruz Province in Argentina, South America, with other fossils of the genus known from New Zealand, eastern Australia, and possibly North America. Other fossils of the subfamily (such as Athrotaxites) are known from the Late Jurassic of Europe and India, as well as the Early Cretaceous of North America and China,[4] as well as possibly the Early Cretaceous of Europe, and Late Cretaceous of South America and North America.[5]
Species
| Phylogeny of Athrotaxis[6][7] | |||||||||||||||
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The three taxa of Athrotaxis are variously treated as three distinct species, or as two species, with the third taxon being a hybrid between the other two. There is strong genetic evidence that the third taxon is a hybrid.[8]
| Image | Leaves | Scientific name | Description | Distribution |
|---|---|---|---|---|
| 120px | 120px | Pencil Pine Athrotaxis cupressoides D.Don. |
Leaves short, 3–5 mm, adpressed tightly on the shoots. Cones small, 1-1.5 cm, scales with a small bract only covering the centre of the scale. | Tasmania, Australia. |
| 120px | 120px | King Billy Pine or King William Pine Athrotaxis selaginoides D.Don. |
Leaves long, 8–14 mm, spreading out from the shoots. Cones large, 2–3 cm, scales with a large bract nearly completely covering the scale. | |
| 120px | 120px | Athrotaxis X laxifolia Hook. | (A. cupressoides × A. selaginoides). Leaves short, 4–7 mm, spreading out from the shoots. Cones intermediate, 1.5-2.5 cm, scales with a medium bract covering most of the scale. |
Cultivation and uses
References
- ↑ 1.0 1.1 1.2 Farjon, A. (2005). Monograph of Cupressaceae and Sciadopitys. Royal Botanic Gardens, Kew. ISBN 1-84246-068-4
- ↑ Kirkpatrick, JB; Dickinson, KJM (1984). "The Impact of Fire on Tasmanian Alpine Vegetation and Soils". Australian Journal of Botany 32 (6): 613. doi:10.1071/bt9840613. ISSN 0067-1924. https://doi.org/10.1071/bt9840613.
- ↑ Stull, Gregory W.; Qu, Xiao-Jian; Parins-Fukuchi, Caroline; Yang, Ying-Ying; Yang, Jun-Bo; Yang, Zhi-Yun; Hu, Yi; Ma, Hong et al. (August 2021). "Gene duplications and phylogenomic conflict underlie major pulses of phenotypic evolution in gymnosperms" (in en). Nature Plants 7 (8): 1015–1025. doi:10.1038/s41477-021-00964-4. ISSN 2055-0278. PMID 34282286. https://www.nature.com/articles/s41477-021-00964-4/.
- ↑ Dong, Chong; Sun, Bai-Nian; Wu, Jing-Yu; Du, Bao-Xia; Xu, Xiao-Hui; Jin, Pei-Hong (January 2014). "Structure and affinities of Athrotaxites yumenensis sp. nov. (Cupressaceae) from the Lower Cretaceous of northwestern China" (in en). Cretaceous Research 47: 25–38. doi:10.1016/j.cretres.2013.09.012. Bibcode: 2014CrRes..47...25D. https://linkinghub.elsevier.com/retrieve/pii/S0195667113001444.
- ↑ Andruchow-Colombo, Ana; Gandolfo, María A.; Escapa, Ignacio H.; Cúneo, Néstor R. (November 2022). "New genus of Cupressaceae from the Upper Cretaceous of Patagonia (Argentina) fills a gap in the evolution of the ovuliferous complex in the family" (in en). Journal of Systematics and Evolution 60 (6): 1417–1439. doi:10.1111/jse.12842. ISSN 1674-4918. https://onlinelibrary.wiley.com/doi/10.1111/jse.12842.
- ↑ Stull, Gregory W.Expression error: Unrecognized word "et". (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. PMID 34282286. https://www.nature.com/articles/s41477-021-00964-4.
- ↑ Stull, Gregory W. (2021). main.dated.supermatrix.tree.T9.tre. Figshare. doi:10.6084/m9.figshare.14547354.v1. https://figshare.com/articles/dataset/Gene_duplications_and_genomic_conflict_underlie_major_pulses_of_phenotypic_evolution_in_gymnosperms/14547354.
- ↑ Worth, James R. P.; Larcombe, Matthew J.; Sakaguchi, Shota; Marthick, James R.; Bowman, David M. J. S.; Ito, Motomi; Jordan, Gregory J. (2016). "Transient hybridization, not homoploid hybrid speciation, between ancient and deeply divergent conifers" (in en). American Journal of Botany 103 (2): 246–259. doi:10.3732/ajb.1500433. ISSN 0002-9122. https://bsapubs.onlinelibrary.wiley.com/doi/10.3732/ajb.1500433.
<ref> tag with name "APNI" defined in <references> is not used in prior text.Template:Acrogymnospermae classification Wikidata ☰ Q1368777 entry
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