Athrotaxis
Encyclopedia
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 altitude temperate rainforests.
They are medium-sized evergreen
tree
s, 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 seed
s; 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.
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.
of Athrotaxis are variously treated as three distinct species, or as two species, with the third taxon being a hybrid between the other two. To date, the evidence has been inconclusive, with some data suggesting hybrid origin, but other evidence suggesting the third is distinct and not a hybrid.
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 attractive ornamental trees with luxuriant foliage, though they are generally only planted in arboretum
s or botanical garden
s. Cultivation away from their native range is successful only in areas with high rainfall, mild winters, and cool summers, such as the British Isles
, the Pacific Northwest
of North America
, and New Zealand
.
Examples of the species and many of its leaf froms may be seen in the living collections at The Tasmanian Arboretum.
Pinophyta
The conifers, division Pinophyta, also known as division Coniferophyta or Coniferae, are one of 13 or 14 division level taxa within the Kingdom Plantae. Pinophytes are gymnosperms. They are cone-bearing seed plants with vascular tissue; all extant conifers are woody plants, the great majority being...
in the cypress family, Cupressaceae
Cupressaceae
The Cupressaceae or cypress family is a conifer family with worldwide distribution. The family includes 27 to 30 genera , which include the junipers and redwoods, with about 130-140 species in total. They are monoecious, subdioecious or dioecious trees and shrubs from 1-116 m tall...
. The genus is endemic
Endemic (ecology)
Endemism is the ecological state of being unique to a defined geographic location, such as an island, nation or other defined zone, or habitat type; organisms that are indigenous to a place are not endemic to it if they are also found elsewhere. For example, all species of lemur are endemic to the...
to western Tasmania
Tasmania
Tasmania is an Australian island and state. It is south of the continent, separated by Bass Strait. The state includes the island of Tasmania—the 26th largest island in the world—and the surrounding islands. The state has a population of 507,626 , of whom almost half reside in the greater Hobart...
, where they grow in high altitude temperate rainforests.
They are medium-sized evergreen
Evergreen
In botany, an evergreen plant is a plant that has leaves in all seasons. This contrasts with deciduous plants, which completely lose their foliage during the winter or dry season.There are many different kinds of evergreen plants, both trees and shrubs...
tree
Tree
A tree is a perennial woody plant. It is most often defined as a woody plant that has many secondary branches supported clear of the ground on a single main stem or trunk with clear apical dominance. A minimum height specification at maturity is cited by some authors, varying from 3 m to...
s, reaching 10-30 m (rarely 40 m) tall and 1-1.5 m trunk diameter. The leaves
Leaf
A leaf is an organ of a vascular plant, as defined in botanical terms, and in particular in plant morphology. Foliage is a mass noun that refers to leaves as a feature of plants....
are scale-like, 3-14 mm long, are borne spirally on the shoots. The cones
Conifer cone
A cone is an organ on plants in the division Pinophyta that contains the reproductive structures. The familiar woody cone is the female cone, which produces seeds. The male cones, which produce pollen, are usually herbaceous and much less conspicuous even at full maturity...
are globose to oval, 1-3 cm diameter, with 15-35 scales, each scale with 3-6 seed
Seed
A seed is a small embryonic plant enclosed in a covering called the seed coat, usually with some stored food. It is the product of the ripened ovule of gymnosperm and angiosperm plants which occurs after fertilization and some growth within the mother plant...
s; 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.
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.
Species
The three taxaTaxon
|thumb|270px|[[African elephants]] form a widely-accepted taxon, the [[genus]] LoxodontaA taxon is a group of organisms, which a taxonomist adjudges to be a unit. Usually a taxon is given a name and a rank, although neither is a requirement...
of Athrotaxis are variously treated as three distinct species, or as two species, with the third taxon being a hybrid between the other two. To date, the evidence has been inconclusive, with some data suggesting hybrid origin, but other evidence suggesting the third is distinct and not a hybrid.
- Athrotaxis cupressoidesAthrotaxis cupressoidesAthrotaxis cupressoides is a species of Athrotaxis, endemic to Tasmania in Australia, where it grows at 700–1,300 m altitude.Its common name is Pencil Pine, although it's not a member of the Pine family....
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. - Athrotaxis selaginoidesAthrotaxis selaginoidesAthrotaxis 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...
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. - Athrotaxis laxifoliaAthrotaxis laxifoliaAthrotaxis laxifolia is a species of Athrotaxis, endemic to Tasmania in Australia, where it grows at 1,000–1,200 m altitude.It is an evergreen coniferous tree growing to 10–20 m tall, with a trunk up to 1 m diameter. The leaves are scale-like, 4–12 mm long and 2–3 mm broad, arranged spirally on the...
Hook.William Jackson HookerSir William Jackson Hooker, FRS was an English systematic botanist and organiser. He held the post of Regius Professor of Botany at Glasgow University, and was the first Director of the Royal Botanic Gardens, Kew. He enjoyed the friendship and support of Sir Joseph Banks for his exploring,...
(? 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
The woodWood
Wood is a hard, fibrous tissue found in many trees. It has been used for hundreds of thousands of years for both fuel and as a construction material. It is an organic material, a natural composite of cellulose fibers embedded in a matrix of lignin which resists compression...
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 attractive ornamental trees with luxuriant foliage, though they are generally only planted in arboretum
Arboretum
An arboretum in a narrow sense is a collection of trees only. Related collections include a fruticetum , and a viticetum, a collection of vines. More commonly, today, an arboretum is a botanical garden containing living collections of woody plants intended at least partly for scientific study...
s or botanical garden
Botanical garden
A botanical garden The terms botanic and botanical, and garden or gardens are used more-or-less interchangeably, although the word botanic is generally reserved for the earlier, more traditional gardens. is a well-tended area displaying a wide range of plants labelled with their botanical names...
s. Cultivation away from their native range is successful only in areas with high rainfall, mild winters, and cool summers, such as the British Isles
British Isles
The British Isles are a group of islands off the northwest coast of continental Europe that include the islands of Great Britain and Ireland and over six thousand smaller isles. There are two sovereign states located on the islands: the United Kingdom of Great Britain and Northern Ireland and...
, the Pacific Northwest
Pacific Northwest
The Pacific Northwest is a region in northwestern North America, bounded by the Pacific Ocean to the west and, loosely, by the Rocky Mountains on the east. Definitions of the region vary and there is no commonly agreed upon boundary, even among Pacific Northwesterners. A common concept of the...
of North America
North America
North America is a continent wholly within the Northern Hemisphere and almost wholly within the Western Hemisphere. It is also considered a northern subcontinent of the Americas...
, and New Zealand
New Zealand
New Zealand is an island country in the south-western Pacific Ocean comprising two main landmasses and numerous smaller islands. The country is situated some east of Australia across the Tasman Sea, and roughly south of the Pacific island nations of New Caledonia, Fiji, and Tonga...
.
Examples of the species and many of its leaf froms may be seen in the living collections at The Tasmanian Arboretum.