|Cupressus sempervirens foliage and cones|
Cupressaceae is a
decussate pairs (opposite pairs, each pair at 90° to the previous pair) or in decussate whorls of three or four, depending on the genus. On young plants, the leaves are needle-like, becoming small and scale-like on mature plants of many genera; some genera and species retain needle-like leaves throughout their lives. Old leaves are mostly not shed individually, but in small sprays of foliage (cladoptosis); exceptions are leaves on the shoots that develop into branches. These leaves eventually fall off individually when the bark starts to flake. Most are evergreen with the leaves persisting 2–10 years, but three genera (Glyptostrobus, Metasequoia and Taxodium) are deciduousor include deciduous species.
pollen cones are more uniform in structure across the family, 1–20 mm long, with the scales again arranged spirally, decussate (opposite) or whorled, depending on the genus; they may be borne singly at the apex of a shoot (most genera), in the leaf axils (Cryptomeria), in dense clusters (Cunninghamia and Juniperus drupacea), or on discrete long pendulous panicle-like shoots (Metasequoia and Taxodium).
Cupressaceae is a widely distributed conifer family, with a near-global range in all continents except for Antarctica, stretching from 70°N in arctic
Pilgerodendron uviferum), further south than any other conifer species. Juniperus indica reaches 4930 m altitude in Tibet. Most habitats on land are occupied, with the exceptions of polar tundra and tropical lowland rainforest (though several species are important components of temperate rainforests and tropical highland cloud forests); they are also rare in deserts, with only a few species able to tolerate severe drought, notably Cupressus dupreziana in the central Sahara. Despite the wide overall distribution, many genera and species show very restricted relictual distributions, and many are endangered species.
The world's largest (Sequoiadendron giganteum) and tallest (Sequoia sempervirens) trees belong to the Cupressaceae, as do six of the ten longest-lived tree species.
Taiwania cryptomerioidesMendocino Coast Botanical Gardens, Fort Bragg
Molecular and morphological studies have expanded Cupressaceae to include the genera of
Cupressoideae. The former Taxodiaceae genus, Sciadopitys, has been moved to a separate monotypic family Sciadopityaceae due to being genetically distinct from the rest of the Cupressaceae. In some classifications Cupressaceae is raised to an order, Cupressales. Molecular evidence supports Cupressaceae being the sister group to the yews (family Taxaceae), from which it diverged during the early-mid Triassic. The clade comprising both is sister to Sciadopityaceae, which diverged from them during the early-mid Permian. The oldest definitive record of Cupressaceae is Austrohamia minuta from the Early Jurassic (Pliensbachian) of Patagonia, known from many parts of the plant. The reproductive structures of Austrohamia have strong similarities to those of the primitive living cypress genera Taiwania and Cunninghamia. By the Middle to Late Jurassic Cupressaceae were abundant in warm temperate–tropical regions of the Northern Hemisphere. The diversity of the group continued to increase during the Cretaceous period. The earliest appearance of the non-taxodiaceous Cupressaceae (the clade containing Callitroideae and Cupressoideae) is in the mid-Cretaceous, represented by "Widdringtonia" americana from the Cenomanian of North America, and they subsequently diversified during the Late Cretaceous and early Cenozoic.
The family is divided into seven subfamilies, based on genetic and morphological analysis as follows:
A 2010 study of Actinostrobus and Callitris places the three species of Actinostrobus within an expanded Callitris based on analysis of 42 morphological and anatomical characters.
Phylogeny based on 2000 study of morphological and molecular data. Several further papers have suggested the segregation Cupressus species into four total genera.
A 2021 molecular study supported a very similar phylogeny but with some slight differences, along with the splitting of Cupressus (found to be paraphyletic):
Many of the species are important
waymarking. Its heartwood is fragrant and used in clothes chests, drawers and closets to repel moths. It is a source of juniper oil used in perfumes and medicines. The wood is also used as long lasting fenceposts and for bows.
Several genera are important in horticulture.
Giant sequoia is a popular ornamental tree and is occasionally grown for timber. Giant sequoia, Leyland cypress, and Arizona cypress are grown to a small extent as Christmas trees.
Some species have significant cultural importance. The
Monterey cypresses are often visited by tourists and photographers, particularly an old tree known as the Lone Cypress.
The fleshy cones of Juniperus communis are used to flavour gin.
Native Americans and early European explorers used Thuja leaves as a cure for scurvy. Distillation of Fokienia roots produces an essential oil called pemou oil used in medicine and cosmetics.
Recent progress on Endophyte Biology in Cupressaceae, by the groups of Jalal Soltani (Bu-Ali Sina University) and Elizabeth Arnold (Arizona University) have revealed prevalent symbioses of endophytes and endofungal bacteria with family Cupressaceae. Furthermore, current and potential uses of Cupressaceous tree's endophytes in agroforestry and medicine is shown by both groups.
The Cupressaceae trees contain a wide range of extractives, especially terpenes and terpenoids, which both have strong and often pleasant odors.
heartwood, bark and leaves are the tree parts richest in terpenes. Some of these compounds are widely distributed in other trees as well, and some are typical for Cupressaceae family. The most known terpenoids found in conifers are sesquiterpenoids, diterpenes and tropolones. Diterpens are commonly found in different types of conifers and are not typical for this family. Some sesquiterpenoids (e.g. bisabolanes, cubenanes, guaianes, ylanganes, himachalanes, longifolanes, longibornanes, longipinanes, cedranes, thujopsanes) also present in Pinaceae, Podocarpaceae and Taxodiaceae. Meanwhile, chamigranes, cuparanes, widdranes and acoranes are more distinctive for Cupressaceae. Tropolone derivatives, such as nootkatin, chanootin and hinokitiolare particularly characteristic for Cupressaceae.
Several genera are an alternate host of Gymnosporangium rust, which damages apples and other related trees in the subfamily Maloideae.
monoicous variants of Austrocedrus and Widdringtonia. However, the females of some species have a very low potential for causing allergies (an OPALS allergy scale rating of 2 or lower) including Austrocedrus females and Widdringtonia females.