Cupressus
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The genus Cupressus is one of several genera within the family Cupressaceae that have the common name cypress; for the others, see cypress (disambiguation).
As currently treated, these cypresses are native to scattered localities in mainly warm temperate regions in the northern hemisphere, including western North America, Central America, north-west Africa, the Middle East, the Himalaya, southern China and north Vietnam. They are evergreen trees or large shrubs, growing to 5-40 m tall. The leaves are scale-like, 2-6 mm long, arranged in opposite decussate pairs, and persist for 3-5 years. On young plants up to 1-2 years old, the leaves are needle-like, 5-15 mm long. The cones are 8-40 mm long, globose or ovoid with 4-14 scales arranged in opposite decussate pairs; they are mature in 18-24 months from pollination. The seeds are small, 4-7 mm long, with two narrow wings, one along each side of the seed.
Many of the species are adapted to forest fires, holding their seeds for many years in closed cones until the parent trees are killed by a fire; the seeds are then released to colonise the bare, burnt ground. In other species, the cones open at maturity to release the seeds.
Many species are grown as decorative trees in parks and, in Asia, around temples; in some areas, the native distribution is hard to discern due to extensive cultivation. A few species are grown for their timber, which can be very durable. The fast-growing hybrid Leyland Cypress, much used in gardens, draws one of its parents from this genus (Monterey Cypress C. macrocarpa); the other parent, Nootka Cypress, is also sometimes classified in this genus, or else in the separate genus Callitropsis, but in the past more usually in Chamaecyparis.
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Species
The number of species recognised within this genus varies sharply, from 16 to 25 or more according to the authority followed. This is because most populations are small and isolated, and it is difficult to be sure whether they should be accorded specific, subspecific or varietal rank. Current tendencies are to reduce the number of recognised species; when a narrow species concept is adopted, the varieties indented in the list below may also be accepted as distinct species. See also the New World species (below) for a likely split in the genus in the future.
Old World species
The Old World cypresses tend to have cones with more scales (8-14 scales, rarely 6 in C. funebris), each scale with a short broad ridge, not a spike. Cupressus sempervirens is the type species of the genus, defining the name Cupressus.
- Cupressus cashmeriana (Bhutan Cypress) - Conservation status: Vulnerable
- Cupressus chengiana (Cheng's Cypress) - Conservation status: Vulnerable
- Cupressus duclouxiana (Yunnan Cypress) - Conservation status: Data deficient
- Cupressus dupreziana (Saharan Cypress) - Conservation status: Critical
- Cupressus atlantica (C. dupreziana var. atlantica; Moroccan Cypress) - Conservation status: Endangered
- Cupressus funebris (Weeping Cypress) - Conservation status: Secure
- Cupressus gigantea (Tibetan Cypress) - Conservation status: Vulnerable
- Cupressus sempervirens (Mediterranean Cypress) - Conservation status: Secure
- Cupressus torulosa (Himalayan Cypress) - Conservation status: Lower risk
New World species
The New World cypresses tend to have cones with fewer scales (4-8 scales, rarely more in C. macrocarpa), each scale with an often prominent narrow spike. Very recent genetic evidence (Little et al., November 2004) shows that they are less closely related to the Old World cypresses than previously thought, being more closely related to Callitropsis and Juniperus than to the rest of Cupressus. A change in generic classification for these species is therefore likely in the near future, either to Callitropsis or to a new genus.
- Cupressus arizonica (Arizona Cypress) - Conservation status: Secure
- Cupressus arizonica var. glabra (C. glabra; Smooth Arizona Cypress) - Conservation status: Secure
- Cupressus arizonica var. montana (C. montana; San Pedro Martir Cypress) - Conservation status: Vulnerable
- Cupressus arizonica var. nevadensis (C. nevadensis; Piute Cypress) - Conservation status: Lower risk
- Cupressus arizonica var. stephensonii (C. stephensonii; Cuyamaca Cypress) - Conservation status: Critical
- Cupressus bakeri (Modoc Cypress) - Conservation status: Vulnerable
- Cupressus goveniana (Gowen Cypress) - Conservation status: Vulnerable
- Cupressus goveniana var. pygmaea (C. pygmaea; Mendocino Cypress) - Conservation status: Vulnerable
- Cupressus goveniana var. abramsiana (C. abramsiana; Santa Cruz Cypress) - Conservation status: Endangered
- Cupressus guadalupensis (Guadalupe Cypress) - Conservation status: Critical
- Cupressus guadalupensis var. forbesii (C. forbesii; Tecate Cypress - Conservation status: Vulnerable
- Cupressus lusitanica (Portuguese Cypress or Mexican Cypress) - Conservation status: Secure
- Cupressus lusitanica var. benthamii (C. benthamii; Bentham's Cypress) - Conservation status: Lower risk
- Cupressus macnabiana (Macnab Cypress) - Conservation status: Secure
- Cupressus macrocarpa (Monterey Cypress) - Conservation status: Vulnerable
- Cupressus sargentii (Sargent Cypress) - Conservation status: Secure
- Callitropsis nootkatensis (Nootka Cypress) is also sometimes treated as Cupressus nootkatensis
References
- Little, D. P., Schwarzbach, A. E., Adams, R. P. & Hsieh, Chang-Fu. 2004. The circumscription and phylogenetic relationships of Callitropsis and the newly described genus Xanthocyparis (Cupressaceae). American Journal of Botany 91 (11): 1872–1881. Abstract (http://www.amjbot.org/cgi/content/abstract/91/11/1872)de:Zypressen