| Athrotaxis | |
|---|---|
 | |
| Athrotaxis cupressoides | |
Scientific classification | |
| Kingdom: | Plantae |
| Clade: | Tracheophytes |
| Clade: | Gymnospermae |
| Division: | Pinophyta |
| Class: | Pinopsida |
| Order: | Cupressales |
| Family: | Cupressaceae |
| Subfamily: | Athrotaxidoideae Quinn |
| Genus: | Athrotaxis D.Don[1] |
| Type species | |
| Athrotaxis selaginoides Don | |
| Species | |
See text | |
Athrotaxis is a genus of two to three species (depending on taxonomic opinion) ofconifers in the cypress family,Cupressaceae. The genus isendemic to westernTasmania, where they grow in high-elevationtemperate rainforests.[2]
They are medium-sizedevergreentrees, reaching 10–30 m (rarely 40 m) tall and 1-1.5 m trunk diameter. Theleaves are scale-like, 3–14 mm long, are borne spirally on the shoots. Thecones are globose to oval, 1–3 cm diameter, with 15-35 scales, each scale with 3-6seeds; 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.[2]
They are very susceptible tobush fires, and have declined markedly in abundance due to accidental and deliberate fires since the European colonisation of Tasmania.[2]
Athrotaxis is the only living genus of the subfamily Athrotaxidoideae. A 2021 molecular study found the Athrotaxidoideae to be the sister group to theSequoioideae, which contains famously massive species such as thecoast redwood (Sequoia sempervirens) andgiant 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 lateJurassic.[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 are known from the Late Jurassic of Europe, 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]
| Phylogeny ofAthrotaxis[6][7] | |||||||||||||||
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The threetaxa ofAthrotaxis are variously treated as three distinct species, or as two species, with the third taxon being ahybrid between the other two. There is strong genetic evidence that the third taxon is a hybrid.[8]
| Image | Leaves | Scientific name | Description | Distribution |
|---|---|---|---|---|
 | .jpg) | Pencil Pine Athrotaxis cupressoidesD.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. |
 |  | King Billy Pine or King William Pine Athrotaxis selaginoidesD.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. | Tasmania, Australia. |
 |  | Athrotaxis X laxifoliaHook. | (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. | Tasmania, Australia. |
Thewood is scented and durable, and was extensively used in the past in Tasmania, but is now too rare for any cutting. All three make very attractiveornamental trees with luxuriant foliage, though they are generally only planted inarboretums orbotanical gardens. Cultivation away from their native range is successful only in areas with high rainfall, mild winters, and cool summers, such as theBritish Isles, thePacific Northwest ofNorth America, andNew Zealand.[citation needed]
Examples of the species and many of its leaf forms may be seen in the living collections atThe Tasmanian Arboretum.[citation needed]
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