Description

''Athrotaxis laxifolia'' is an

evergreen In botany, an evergreen is a plant which has foliage that remains green and functional through more than one growing season. This also pertains to plants that retain their foliage only in warm climates, and contrasts with deciduous plants, which ...

coniferous Conifers are a group of cone-bearing seed plants, a subset of gymnosperms. Scientifically, they make up the division Pinophyta (), also known as Coniferophyta () or Coniferae. The division contains a single extant class, Pinopsida. All extant ...

tree In botany, a tree is a perennial plant with an elongated stem, or trunk, usually supporting branches and leaves. In some usages, the definition of a tree may be narrower, including only woody plants with secondary growth, plants that are ...

growing to 12–21 m tall with a conical, sparsely branched crown and a trunk up to 1m diameter. It is commonly known as the Summit or Yellow-Twig athrotaxis. The

leaves A leaf (plural, : leaves) is any of the principal appendages of a vascular plant plant stem, stem, usually borne laterally aboveground and specialized for photosynthesis. Leaves are collectively called foliage, as in "autumn foliage", wh ...

are scale-like, 4–12 mm long and 2–3 mm broad, arranged spirally on the shoots. The

seed cones A conifer cone (in formal botanical usage: strobilus, plural strobili) is a seed-bearing organ on gymnosperm plants. It is usually woody, ovoid to globular, including scales and bracts arranged around a central axis, especially in conifers an ...

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.Farjon, A. (2005). ''Monograph of Cupressaceae and Sciadopitys''. Royal Botanic Gardens, Kew. The bark of ''A. laxifolia'' is dark orange-brown, deeply fissured and flaky. The species name ''laxifolia'' refers to the wider spacing of the leaves as compared with the other conifers in its genus, ''Athrotaxis cuppressoides'' and ''Athrotaxis selaginoides''.

Habitat and distribution

''Athrotaxis laxifolia'' is

endemic Endemism is the state of a species being found in a single defined geographic location, such as an island, state, nation, country or other defined zone; organisms that are indigenous to a place are not endemic to it if they are also found elsew ...

Tasmania ) , nickname = , image_map = Tasmania in Australia.svg , map_caption = Location of Tasmania in AustraliaCoordinates: , subdivision_type = Country , subdi ...

Australia Australia, officially the Commonwealth of Australia, is a Sovereign state, sovereign country comprising the mainland of the Australia (continent), Australian continent, the island of Tasmania, and numerous List of islands of Australia, sma ...

, where it grows between 1,000–1,200 m altitude, in sub-alpine and alpine woodland. One group of researchers have located nine different geographic locations for this species (5 hybrid populations and 4 single individuals). 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. Away from its native range, it is occasionally cultivated as an

ornamental tree Ornamental plants or garden plants are plants that are primarily grown for their beauty but also for qualities such as scent or how they shape physical space. Many flowering plants and garden varieties tend to be specially bred cultivars that i ...

in northwestern

Europe Europe is a large peninsula conventionally considered a continent in its own right because of its great physical size and the weight of its history and traditions. Europe is also considered a Continent#Subcontinents, subcontinent of Eurasia ...

. Despite being the rarest of the three in the wild, it is the most frequently planted ''Athrotaxis'' in cultivation, though still only seen in major collections; trees in

Ireland Ireland ( ; ga, Éire ; Ulster Scots dialect, Ulster-Scots: ) is an island in the Atlantic Ocean, North Atlantic Ocean, in Northwestern Europe, north-western Europe. It is separated from Great Britain to its east by the North Channel (Grea ...

have reached 20 m tall.Mitchell, A. F. (1974). ''A Field Guide to the Trees of Britain and Northern Europe''. Collins Tree Register of the British Isles

Threats and conservation

Its status in the wild is little-known; it is the rarest of the three species of ''Athrotaxis''. It is in many respects intermediate between ''

Athrotaxis cupressoides ''Athrotaxis cupressoides'', is also known as pencil pine, despite being a species of the family Cupressaceae, and not a member of the pine family. Found either as an erect shrub or as a tree, this species is endemic to Tasmania, Australia. Trees ...

'' and ''

Athrotaxis selaginoides ''Athrotaxis selaginoides'' is a species of ''Athrotaxis'', endemic to Tasmania in Australia, where it grows at 400–1,120 m altitude. In its habitat in the mountains, snow in winter is very usual. It is often called King Billy Pine or King Wi ...

'', and it is strongly suspected of being a natural

hybrid Hybrid may refer to: Science * Hybrid (biology), an offspring resulting from cross-breeding ** Hybrid grape, grape varieties produced by cross-breeding two ''Vitis'' species ** Hybridity, the property of a hybrid plant which is a union of two dif ...

between these two; however, genetic evidence for this is inconclusive. Later research has supported the theory of natural hybridization, as populations of ''A. laxifolia'' have been genetically studied and revealed to contain a range of genetic variance from pure ''A. cupressoides'' to pure ''A. selaginoides,'' and some genetically half-way between both. Although listed as Endangered in the IUCN Red List of Threatened Species, the same research has suggested that this classification is unwarranted. Even though ''A. 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.

References

{{Taxonbar, from=Q145640 Cupressaceae Pinales of Australia Vulnerable flora of Australia Flora of Tasmania Endemic flora of Tasmania Ornamental trees Taxonomy articles created by Polbot