Actinostrobus

Taxobox
name = "Actinostrobus"
regnum = Plantae
divisio = Pinophyta
classis = Pinopsida
ordo = Pinales
familia = Cupressaceae
subfamilia = Callitroideae
genus = "Actinostrobus"
genus_authority = Miq.
subdivision_ranks = Species
subdivision = See text

"Actinostrobus" is a genus of coniferous trees in the Cupressaceae (cypress family). Common names include cypress and cypress-pine, the latter name shared by the closely related genus "Callitris". There are three species in the genus, all endemic to southwestern Western Australia:
*"Actinostrobus acuminatus" - Dwarf Cypress
*"Actinostrobus arenarius"
*"Actinostrobus pyramidalis" - Swan River Cypress or Swamp Cypress

They are shrubs or small trees, reaching 3–8 m [(10–26 ft)] tall. The leaves are evergreen, of two forms; juvenile needle-like leaves 10–20 mm [(0.4–0.8 in)] long on young seedlings (but occasional into adulthood in "A. acuminatus"), and scale-like adult leaves, 2–8 mm [(0.1–0.25 in)] long with only the apex free. The leaves are arranged in six rows along the twigs, in alternating whorls of three.

The male cones are small, 3–6 mm [(0.1–0.25 in)] long, and are located at the tips of the twigs. The female cones start out similarly inconspicuous, maturing in eighteen to twenty months to 10–20 mm [(0.4–0.8 in)] long and wide, globular to acute-ovoid, with six thick, woody scales, arranged in two whorls of three, and a further nine to fifteen thin, sterile basal scales. The cones remain closed on the trees for many years, opening only after being scorched by a bushfire; this then releases the seeds to grow on the newly cleared burnt ground.

The closest relative of "Actinostrobus" is "Callitris", which is much more widespread, occurring in most of Australia, and differs in its cones lacking the basal whorls of small sterile scales.

The wood of "Actinostrobus" is light, soft and aromatic, but the plants are too small for any significant use. They are occasionally planted as ornamental shrubs, but their use is restricted by the high risks imposed by their very high flammability in bushfires.

US conversions

References

*
*Farjon, A. (2005). "Monograph of Cupressaceae and Sciadopitys". Royal Botanic Gardens, Kew. ISBN 1-84246-068-4.
* [http://www.conifers.org/cu/ac/index.htm Gymnosperm Database - "Actinostrobus"]
* [http://www.pinetum.org/cones/CAcones.htm Arboretum de Villardebelle - Photos of cones]