| Athrotaxis laxifolia | |
|---|---|
 | |
Scientific classification | |
| Kingdom: | Plantae |
| Clade: | Tracheophytes |
| Clade: | Gymnospermae |
| Division: | Pinophyta |
| Class: | Pinopsida |
| Order: | Cupressales |
| Family: | Cupressaceae |
| Genus: | Athrotaxis |
| Species: | A. laxifolia |
| Binomial name | |
| Athrotaxis laxifolia | |
Athrotaxis x laxifolia is a tree belonging to the genusAthrotaxis endemic to Tasmania. It is a hybrid betweenAthrotaxis cupressoides andAthrotaxis selaginoides.
Athrotaxis x laxifolia is anevergreenconiferoustree growing to 12–21 m tall with a sparsely branched crown,[2] an irregular growth habit and a trunk up to 1m diameter. Theleaves are scale-like, 4–12 mm long and 2–3 mm broad, arranged spirally on the shoots. Theseed cones are oblong-globose, 15–26 mm long and 14–20 mm diameter, with 14–18 spirally-arranged scales; they are mature about six months after pollination. The pollen cones are 3–5 mm long.[3] The bark ofA. laxifolia is dark orange-brown, deeply fissured and flaky.[2] The species namelaxifolia refers to the wider spacing of the leaves as compared with the other conifers in its genus,Athrotaxis cuppressoides andAthrotaxis selaginoides.[2]
Athrotaxis x laxifolia isendemic toTasmania,Australia, where it grows between 1,000–1,200 m altitude, in sub-alpine and alpine woodland.[3][1] One group of researchers have located nine different geographic locations for this species (5 hybrid populations and 4 single individuals).[4] The hybrid populations were found at Mount Reid, Tyndall Range, Crooked Lake, Brumbys Creek, and Tarn Shelf, while the individuals are located at Mount Kate, Pine Lake, Wylds Craig and Lake Dobson Road.[4]
Away from its native range, it is occasionally cultivated as anornamental tree in northwesternEurope. Despite being the rarest of the three in the wild, it is the most frequently plantedAthrotaxis in cultivation, though still only seen in major collections; trees inIreland have reached 20 m tall.[5][6]
Its status in the wild is little-known; it is the rarest of the three species ofAthrotaxis. It is in many respects intermediate betweenAthrotaxis cupressoides andAthrotaxis selaginoides, and it is strongly suspected of being a naturalhybrid between these two. Research has supported the theory of natural hybridization, as populations ofA. laxifolia have been genetically studied which revealed that many individuals across the range of this taxon are genetically consistent with being first generation hybrids, although two well-established populations are advanced generation hybrids betweenA. cupressoides andA. selaginoides.[4] This genetic evidence indicates that these latter two populations are slowly disappearing through the process of repeated hybridisation withAthrotaxis selaginoides. Although listed as Endangered in the IUCN Red List of Threatened Species, the same research has suggested that this classification is unwarranted.[4] Even thoughA. laxifolia is rare in itself, given the multiple spontaneous hybridization events, it should be afforded the same status as its parent species (A. cuppresoides and A. selaginoides) which is Vulnerable.[4]
