''Cupressus dupreziana'', the Saharan cypress, or tarout, is a very rare

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 ext ...

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 ...

native to the

Tassili n'Ajjer Tassili n'Ajjer ( Berber: ''Tassili n Ajjer'', ar, طاسيلي ناجر; "Plateau of rivers") is a national park in the Sahara desert, located on a vast plateau in southeastern Algeria. Having one of the most important groupings of prehistoric ...

mountains in the central

Sahara desert , photo = Sahara real color.jpg , photo_caption = The Sahara taken by Apollo 17 astronauts, 1972 , map = , map_image = , location = , country = , country1 = , ...

, southeast

Algeria ) , image_map = Algeria (centered orthographic projection).svg , map_caption = , image_map2 = , capital = Algiers , coordinates = , largest_city = capital , relig ...

, where it forms a unique population of trees hundreds of kilometres from any other trees. There are only 233 specimens of this

endangered species An endangered species is a species that is very likely to become extinct in the near future, either worldwide or in a particular political jurisdiction. Endangered species may be at risk due to factors such as habitat loss, poaching and inv ...

, the largest about 22 m tall. The majority are estimated to be over 2000 years old, with very little regeneration due to the increasing

desertification Desertification is a type of land degradation in drylands in which biological productivity is lost due to natural processes or induced by human activities whereby fertile areas become increasingly arid. It is the spread of arid areas caused ...

of the Sahara. Rainfall totals in the area are estimated to be about 30 mm annually. The largest one is named Tin-Balalan is believed to be the oldest tarout tree with a circumference of 12 meters or 36 feet. This species is distinct from the allied ''

Cupressus sempervirens ''Cupressus sempervirens'', the Mediterranean cypress (also known as Italian cypress, Tuscan cypress, Persian cypress, or pencil pine), is a species of cypress native to the eastern Mediterranean region, in northeast Libya, southern Albania, so ...

'' (Mediterranean cypress) in its much bluer foliage with a white resin spot on each

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

, the smaller shoots often being flattened in a single plane. It also has smaller cones, only 1.5–2.5 cm long. '' Cupressus atlantica'' (Moroccan cypress) is more similar, and is treated as a variety of the Saharan cypress (''C. dupreziana'' var. ''atlantica'') by some authors. Probably as a result of its isolation and low population, the Saharan cypress has

evolved Evolution is change in the heritable characteristics of biological populations over successive generations. These characteristics are the expressions of genes, which are passed on from parent to offspring during reproduction. Variati ...

a unique reproductive system of male apomixis whereby 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 develop entirely from the genetic content of the

pollen Pollen is a powdery substance produced by seed plants. It consists of pollen grains (highly reduced microgametophytes), which produce male gametes (sperm cells). Pollen grains have a hard coat made of sporopollenin that protects the gametop ...

. There is no genetic input from the female "parent", which only provides nutritional sustenance. The Moroccan cypress does not share this characteristic. The Saharan cypress is occasionally cultivated in southern and western

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 ...

, in part for ''ex situ'' genetic conservation, but also 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 ...

. An international arboretum is being established in

Canberra Canberra ( ) is the capital city of Australia. Founded following the federation of the colonies of Australia as the seat of government for the new nation, it is Australia's largest inland city and the eighth-largest city overall. The ci ...

Australian Capital Territory The Australian Capital Territory (commonly abbreviated as ACT), known as the Federal Capital Territory (FCT) until 1938, is a landlocked federal territory of Australia containing the national capital Canberra and some surrounding township#Aust ...

(ACT), Australia within which will be established forests of rare and endangered species from throughout the world. One of these forests is dedicated to ''Cupressus dupreziana'' and 1300 of the trees have been propagated for planting in late 2007.

Notes

References

* Stewart, P.J. 1969. ''Cupressus dupreziana'', threatened conifer of the Sahara. ''Biological Conservation'' 2: 10-12. * Pichot, C., Fady, B., & Hochu, I. 2000. Lack of mother tree alleles in zymograms of ''Cupressus dupreziana'' A. Camus embryos. ''Ann. For. Sci.'' 57: 17–22
Full article (pdf file)
* Pichot, C., El Maátaoui, M., Raddi, S. & Raddi, P. 2001. Surrogate mother for endangered ''Cupressus''. ''Nature'' 412: 39. *

External links

Gymnosperm Database: ''Cupressus dupreziana''

Conifers Around the World: ''Cupressus dupreziana'' - Tarout

Cartoonist Michael Leunig's life as a guerrilla gardener on the curly and narrow
"Talking Plants", Radio National, Australian Broadcasting Corporation {{Taxonbar, from=Q1887955 dupreziana Endemic flora of Algeria Flora of North Africa Trees of Algeria Trees of Africa Trees of Mediterranean climate Endangered flora of Africa Plants described in 1926 Garden plants of Africa Ornamental trees Taxa named by Aimée Antoinette Camus