''Callitris'' is a genus of

conifer 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 ext ...

ous

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 ...

s in the

Cupressaceae Cupressaceae is a conifer family, the cypress family, with worldwide distribution. The family includes 27–30 genera (17 monotypic), which include the junipers and redwoods, with about 130–140 species in total. They are monoecious, subdioeci ...

(cypress family). There are 16 recognized species in the genus, of which 13 are native to

Australia Australia, officially the Commonwealth of Australia, is a sovereign country comprising the mainland of the Australian continent, the island of Tasmania, and numerous smaller islands. With an area of , Australia is the largest country by ...

and the other three (''C. neocaledonica, C. sulcata'' and ''C. pancheri'') native to

New Caledonia ) , anthem = "" , image_map = New Caledonia on the globe (small islands magnified) (Polynesia centered).svg , map_alt = Location of New Caledonia , map_caption = Location of New Caledonia , mapsize = 290px , subdivision_type = Sovereign st ...

. Traditionally, the most widely used common name is cypress-pine, a name shared by some species of the closely related genus ''

Actinostrobus ''Actinostrobus'' is a genus of coniferous trees in the Cupressaceae (cypress family). Common names include cypress, sandplain-cypress and cypress-pine, the last of these shared by the closely related genus '' Callitris''. Species There are thre ...

''.Eckenwalder, J.E. 2009. ''Conifers of the World: The Complete Reference''. Timber Press. p. 122-124

Description

They are small to medium-sized

s or large

shrub A shrub (often also called a bush) is a small-to-medium-sized perennial woody plant. Unlike herbaceous plants, shrubs have persistent woody stems above the ground. Shrubs can be either deciduous or evergreen. They are distinguished from tree ...

s, reaching tall (to in ''C. macleayana''). The leaves are

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, whic ...

and scale-like. But young seedlings have needle-like leaves; in ''C. macleayana'', needle-like leaves are found mixed with scale leaves throughout the tree's life. The scales are arranged in six rows along the twigs, in alternating whorls of three (often in whorls of four in ''C. macleayana''). The male cones are small, long, and are located at the tips of the twigs. The female cones start out similarly inconspicuous, maturing in 18–20 months to long and wide, globular to ovoid (acute in ''C. macleayana''), with six overlapping, thick, woody scales, arranged in two whorls of three (often 8 scales in ''C. macleayana''). The cones remain closed on the trees for many years, opening only after being scorched by a bushfire; this then releases the

seed A seed is an embryonic plant enclosed in a protective outer covering, along with a food reserve. The formation of the seed is a part of the process of reproduction in seed plants, the spermatophytes, including the gymnosperm and angiosper ...

s to grow on the newly cleared burnt ground.

Taxonomy

The genus is divided into two sections, with the atypical ''C. macleayana'' in sect. ''Octoclinis'', and all the other species in sect. ''Callitris''. Some botanists treat ''C. macleayana'' in a separate genus, as ''Octoclinis macleayana''. ''C. macleayana'' is also distinct in occurring in

rainforest Rainforests are characterized by a closed and continuous tree canopy, moisture-dependent vegetation, the presence of epiphytes and lianas and the absence of wildfire. Rainforest can be classified as tropical rainforest or temperate rainfores ...

on the east coast of Australia; the other species all grow on dry sites. The closest relative of ''Callitris'' is ''

'' from southwest

Western Australia Western Australia (commonly abbreviated as WA) is a state of Australia occupying the western percent of the land area of Australia excluding external territories. It is bounded by the Indian Ocean to the north and west, the Southern Ocean to t ...

, which differs in its cones having several basal whorls of small sterile scales. A 2010 study of ''Actinostrobus'' and ''Callitris'' places the three species of ''Actinostrobus'' within an expanded ''Callitris'' based on analysis of 42 morphological and anatomical characters. In 2010, early

Oligocene The Oligocene ( ) is a geologic epoch of the Paleogene Period and extends from about 33.9 million to 23 million years before the present ( to ). As with other older geologic periods, the rock beds that define the epoch are well identified but t ...

fossilised foliage and cones of ''Callitris'' were unearthed near the

Lea River The River Lea is a steep continuous river located in the north-western region of Tasmania, Australia. The river has an average gradient of and a peak grade of that flows from Lake Lea to Lake Gairdner Lake Gairdner is a large endorheic ...

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

. The fossils were given the name ''Callitris leaensis'' and represent the oldest known representative of the genus.

Species

The genus includes the following species: * '' Callitris baileyi'' – SE QLD, NE NSW * '' Callitris canescens'' – S WA, S SA * '' Callitris columellaris'' – south-east QLD (coastal); naturalised in

Hawaii Hawaii ( ; haw, Hawaii or ) is a state in the Western United States, located in the Pacific Ocean about from the U.S. mainland. It is the only U.S. state outside North America, the only state that is an archipelago, and the only stat ...

and southern Florida. Previously synonymous with ''C. glaucophylla'', ''C. endlicheri'' and ''C. intratropica''. * '' Callitris drummondii'' – S WA * '' Callitris endlicheri'' – NSW, QLD, VIC (hilly areas); naturalised in Hawaii and

St Helena Saint Helena () is a British overseas territory located in the South Atlantic Ocean. It is a remote volcanic tropical island west of the coast of south-western Africa, and east of Rio de Janeiro in South America. It is one of three constitu ...

*''

Callitris glaucophylla ''Callitris'' is a genus of coniferous trees in the Cupressaceae (cypress family). There are 16 recognized species in the genus, of which 13 are native to Australia and the other three (''C. neocaledonica, C. sulcata'' and ''C. ...

'' - NSW, Qld, SA, NT, WA (most common) *''Callitris intratropica'' - NT (blue cypress) * '' Callitris macleayana'' – QLD, NSW * '' Callitris monticola'' – QLD, NSW * '' Callitris muelleri'' – NSW * '' Callitris neocaledonica'' –

* '' Callitris oblonga'' – NSW, TAS * '' Callitris pancheri'' –

* ''

Callitris preissii ''Callitris preissii'' is a species of conifer in the family Cupressaceae, endemic to Rottnest Island, Australia. Common names include Rottnest Island pine, Murray pine, maroong, southern cypress pine, or slender cypress pine. The Noongar peopl ...

'' – SA, VIC, WA, NSW * '' Callitris rhomboidea'' – NSW, QLD, VIC, TAS, naturalised on New Zealand's North Island * ''

Callitris roei ''Callitris roei'', or Roe's cypress-pine, is a species of ''Callitris'' native to Australia, where it is endemic to southwestern Western Australia from Moora south to Albany and east to Cape Arid National Park.Farjon, A. (2005). ''Monograp ...

'' – S WA * ''

Callitris sulcata ''Callitris sulcata'' is a species of pinophyta, conifer in the cypress family, Cupressaceae. Its common name is ''Sapin de Comboui''. It is endemism, endemic to New Caledonia, where it grows only in three forested river valleys. It is an endange ...

'' –

* '' Callitris verrucosa'' – SA, VIC, WA, NSW, QLD

Doubtful names

The following names are of doubtful validity: * ''Callitris arenosa'' Sweet, nom. inval., nom. nud., type not cited, identity uncertain. * ''Callitris columellaris'' f. ''glauca'' F.M.Bailey, described from Qld, type not located, identity uncertain (Hill, 1998). * ''Callitris conglobata'' Heynh., nom. inval., nom. nud, described from New Holland, type not located, identity uncertain. * ''Callitris elegans'' Heynh. (or Sieber ex Heynh.), nom. inval., nom. nud, described from " New Holland", type not located, identity uncertain. * ''Callitris intermedia R.T.Baker & H.G.Sm., nom. inval., identity uncertain (Hill, 1998). * ''Callitris montana'' Heynh., nom. inval., nom. nud, described from New Holland, type not located, identity uncertain. * ''Callitris pyramidalis'' Sweet, nom. inval., nom. nud, syn. ''Frenela pyramidalis'' (Sweet) Parl., nom. inval., nom. nud, type not cited, identity uncertain. * ''Callitris macrocarpa'' Vent., nom. inval. nom. nud, syn ''Cupressus macrocarpa'' (Vent.) A.Cunn., nom. inval., identity uncertain.

Human use

The wood of cypress-pines is light, soft and aromatic. It can be easily split and resists decay; cypress-pine is also

termite Termites are small insects that live in colonies and have distinct castes ( eusocial) and feed on wood or other dead plant matter. Termites comprise the infraorder Isoptera, or alternatively the epifamily Termitoidae, within the order Blat ...

resistant. It is used to make furniture, indoor and outdoor paneling, and fence posts. Cypress-pines are occasionally planted as ornamental trees, but their use is restricted by the high risks imposed by their very high flammability in bushfires. Previously a plantation of ''C. intratropica'' was established outside of Darwin for use in house construction. After Cyclone Tracey it was realised that the timber did not resist strong winds and the plantation was abandoned. The trees are now used for the production of a blue essential oil, rich in guaiol and chamazulene (the blue compound). A number of therapeutic effects are attributed to the essential oil, including antimicrobial and anti-inflammatory effects.

References

External links

Gymnosperm Database - ''Callitris''

{{Taxonbar, from=Q2246875 Conifer genera pl:Cyprzyk