Cupressus

Cypress 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 three to five years. On young plants up to two years old, the leaves are needle-like and 5–15 mm long. The cones are 8–40 mm long, globose or ovoid with four to 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.

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, northwest Africa, the Middle East, the Himalayas, southern China and northern Vietnam. As with other conifers, extensive cultivation has led to a wide variety of forms, sizes and colours, that are grown in parks and gardens throughout the world.[4]

Many species of cypress 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 (Cupressus × leylandii), much used in gardens, draws one of its parents from this genus (Cupressus macrocarpa, Monterey cypress); the other parent, Callitropsis nootkatensis (Nootka cypress), is also sometimes classified in this genus, or else in the separate genus Xanthocyparis, but in the past more usually in Chamaecyparis.

It was believed in the Hellenic culture that the cypress tree was sacred to the gods and it is now used as an emblem of grief. The name of the genus comes from Cyparissos, a young man loved by Apollo, very attached to a deer which he ended up killing by mistake during a hunting trip. To ease the pain Apollo transformed the boy into a plant. The association with mourning continued in Roman times, up to the present day, also for a practical reason: the roots of the cypress are straight into the ground, and expand slightly laterally, not damaging the burials.

There has long been significant uncertainty about the New World members of Cupressus, with several studies recovering them as forming a distinct clade from the Old World members. A 2021 molecular study found Cupressus to be the sister genus to Juniperus, whereas the western members (classified in Callitropsis and Hesperocyparis) were found to be sister to Xanthocyparis.[5]

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. C. sempervirens is the type species of the genus, defining the name Cupressus. They are more closely related to Juniperus than to the New World species, with the exception of the Vietnamese golden cypress, which is more closely related to New World species.[5]

Image	Cone	Name	Common Name	Distribution
		Cupressus atlantica	Moroccan cypress	western Morocco
		Cupressus cashmeriana	Bhutan cypress	eastern Himalaya in Bhutan and adjacent areas of Arunachal Pradesh in northeastern India
		Cupressus chengiana	Cheng's cypress	Gansu and Sichuan Provinces, China
		Cupressus duclouxiana (syn: Cupressus austrotibetica)[7]	Yunnan cypress, South Tibet cypress	Yunnan and Sichuan, China
		Cupressus dupreziana	Saharan cypress	southeast Algeria
		Cupressus funebris	Chinese weeping cypress	southwestern and central China
		Cupressus gigantea	Tibetan cypress	Southeast Tibet - China
		Cupressus sempervirens	Mediterranean cypress, type species	northeast Libya, southern Albania, coastal Bulgaria, southern Ukraine (Crimea), coastal Croatia, southern Montenegro, southern Bosnia and Herzegovina, southern Greece, southern Turkey, Cyprus, northern Egypt, western Syria, Lebanon, Malta, Italy, Israel, western Jordan, and Iran
		Cupressus torulosa (syn: Cupressus tonkinensis)	Tonkin cypress, Himalayan cypress	Sichuan of China and in Vietnam
		Cupressus vietnamensis (syn: Xanthocyparis vietnamensis)	Vietnamese cypress, Vietnamese golden cypress	Vietnam

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. Recent genetic evidence[8] shows they are less closely related to the Old World cypresses than previously thought, being more closely related to Xanthocyparis than to the rest of Cupressus. These species have recently been transferred to Hesperocyparis and Callitropsis. New World species are found in marginal habitats with xeric soils, and therefore exhibit a fragmented allopatric pattern of distribution. This type of distribution results in disproportionate local abundance with most species restricted to small neighboring populations.[9]

Image	Cone	Name	Common Name	Distribution
		Cupressus abramsiana (Cupressus goveniana var. abramsiana; Callitropsis abramsiana;)	Santa Cruz cypress	Santa Cruz Mountains of Santa Cruz and San Mateo Counties in west-central California
		Cupressus arizonica (Callitropsis arizonica)	Arizona cypress	southwestern United States (Arizona, Utah, southwestern New Mexico, and southern California, with a few populations in southern Nevada and in the Chisos Mountains of western Texas), and in Mexico (Coahuila, Nuevo León, Chihuahua, Sonora, Durango, Tamaulipas, Zacatecas and northern Baja California).
		Cupressus bakeri (Callitropsis bakeri)	Modoc cypress	northern California and extreme southwestern Oregon
		Cupressus forbesii (Callitropsis forbesii)	Tecate cypress	Santa Ana Mountains of Orange County and in San Diego County within Southern California, and in northern Baja California state of Mexico.
		Cupressus glabra (Callitropsis glabra)	smooth Arizona cypress	Sedona, Arizona
		Cupressus goveniana (Callitropsis goveniana)	Gowen cypress, Californian cypress	Monterey County, California
		Cupressus guadalupensis (Callitropsis guadalupensis )	Guadalupe cypress	Mexico, found only on Guadalupe Island
		Cupressus lusitanica (Callitropsis lusitanica )	Mexican cypress	Mexico and Central America (Guatemala, El Salvador and Honduras)
		Cupressus macnabiana (Callitropsis macnabiana )	Macnab cypress	northern California
		Cupressus macrocarpa (Callitropsis macrocarpa )	Monterey cypress	Cypress Point in Pebble Beach and at Point Lobos near Carmel, California
		Cupressus nevadensis (Callitropsis nevadensis )	Piute cypress	Southern Sierra Nevada, within Kern County, California and Tulare County.
		Cupressus nootkatensis (syn: Xanthocyparis nootkatensis)	Nootka cypress	Vancouver Island, British Columbia, Canada
		Cupressus pigmaea (Cupressus goveniana var. pigmaea; Callitropsis pigmaea )	Mendocino cypress	Mendocino and Sonoma Counties in northwestern California
		Cupressus revealiana	El Rincon cypress	Baja California in northwestern Mexico
		Cupressus sargentii (Callitropsis sargentii)	Sargent cypress	Mendocino County southwards to Santa Barbara County California
		Cupressus stephensonii (Callitropsis stephensonii )	Cuyamaca cypress	San Diego County California

All plants in the genus Cupressus, including New World Cupressus (now Callitropsis), are extremely allergenic, and have an OPALS allergy scale rating of 10. In warm, Mediterranean climates, these plants release large quantities of pollen for approximately seven months each year.[10]

• Farjon, A. (2005). Monograph of Cupressaceae and Sciadopitys. Royal Botanic Gardens, Kew. ISBN 1-84246-068-4.
• Gadek, P. A., Alpers, D. L., Heslewood, M. M., & Quinn, C. J. (2000). Relationships within Cupressaceae sensu lato: a combined morphological and molecular approach. American Journal of Botany 87: 1044–1057. Available online Archived 2009-09-29 at the Wayback Machine.