Callitris is a genus ofconiferoustrees in theCupressaceae (cypress family). There are 16 recognized species in the genus, of which 13 are native toAustralia and the other three (C. neocaledonica, C. sulcata andC. pancheri) native toNew Caledonia.[1] Traditionally, the most widely used common name iscypress-pine,[3] a name shared by some species of the closely related genusActinostrobus.[4]
They are small to medium-sizedtrees or largeshrubs, reaching 5–25 m (16–82 ft) tall (to 40 m (130 ft) inC. macleayana). Theleaves areevergreen and scale-like, but young seedlings have needle-like leaves; inC. 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 inC. macleayana).
The malecones are small, 3–6 mm (0.12–0.24 in) long, and are located at the tips of the twigs. The female cones start out similarly inconspicuous, maturing in 18–20 months to 1–3 cm (0.39–1.18 in) long and wide, globular to ovoid (acute inC. macleayana), with six overlapping, thick, woody scales, arranged in two whorls of three (often 8 scales inC. macleayana). The cones remain closed on the trees for many years, opening only after being scorched by abushfire; this then releases theseeds to grow on the newly cleared burnt ground.
The genus is divided into two sections, with the atypicalC. macleayana in sect.Octoclinis, and all the other species in sect.Callitris. Some botanists treatC. macleayana in a separate genus, asOctoclinis macleayana.C. macleayana is also distinct in occurring inrainforest on the east coast of Australia; the other species all grow on dry sites.
The closest relative ofCallitris isActinostrobus from southwestWestern Australia, which differs in its cones having several basal whorls of small sterile scales. A 2010 study ofActinostrobus andCallitris places the three species ofActinostrobus within an expandedCallitris based on analysis of 42 morphological and anatomical characters.[5]
In 2010, earlyOligocene fossilised foliage and cones ofCallitris were unearthed near theLea River inTasmania. The fossils were given the nameCallitris leaensis and represent the oldest known representative of the genus.[6]
The wood of cypress-pines is light, soft and aromatic. It can be easily split and resists decay; cypress-pine is alsotermite 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 ofC. intratropica was established outside of Darwin for use in house construction.[11] 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.
^Eckenwalder, J.E. 2009.Conifers of the World: The Complete Reference. Timber Press. p. 122-124
^Piggin, J.; Bruhl, J. J. (2010). "Phylogeny reconstruction ofCallitris Vent. (Cupressaceae) and its allies leads to inclusion ofActinostrobus withinCallitris".Australian Systematic Botany.23 (2):69–93.doi:10.1071/SB09044.
^Paull, Rosemary (2010), "Early Oligocene Callitris and Fitzroya (Cupressaceae) from Tasmania",American Journal of Botany,97 (5):809–820,doi:10.3732/ajb.0900374,PMID21622446
