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 extant conifers are perennial woody plants with secondary growth. The great majority are trees, though a few are shrubs. Examples include cedars, Douglas-firs, cypresses, firs, junipers, kauri, larches, pines, hemlocks, redwoods, spruces, and yews. As of 2002, Pinophyta contained seven families, 60 to 65 genera, and more than 600 living species.
The gymnosperms are a group of seed-producing plants that include conifers, cycads, Ginkgo, and gnetophytes, forming the clade Gymnospermae. The term gymnosperm comes from the composite word in Greek: γυμνόσπερμος, and literally means 'naked seeds'. The name is based on the unenclosed condition of their seeds. The non-encased condition of their seeds contrasts with the seeds and ovules of flowering plants (angiosperms), which are enclosed within an ovary. Gymnosperm seeds develop either on the surface of scales or leaves, which are often modified to form cones, or on their own as in yew, Torreya, and Ginkgo. The life cycle of a gymnosperm involves alternation of generations, with a dominant diploid sporophyte phase, and a reduced haploid gametophyte phase, which is dependent on the sporophytic phase. The term "gymnosperm" is often used in paleobotany to refer to all non-angiosperm seed plants. In that case, to specify the modern monophyletic group of gymnosperms, the term Acrogymnospermae is sometimes used.
The Pinaceae, or pine family, are conifer trees or shrubs, including many of the well-known conifers of commercial importance such as cedars, firs, hemlocks, piñons, larches, pines and spruces. The family is included in the order Pinales, formerly known as Coniferales. Pinaceae have distinctive cones with woody scales bearing typically two ovules, and are supported as monophyletic by both morphological trait and genetic analysis. They are the largest extant conifer family in species diversity, with between 220 and 250 species in 11 genera, and the second-largest in geographical range, found in most of the Northern Hemisphere, with the majority of the species in temperate climates, but ranging from subarctic to tropical. The family often forms the dominant component of boreal, coastal, and montane forests. One species, Pinus merkusii, grows just south of the equator in Southeast Asia. Major centres of diversity are found in the mountains of southwest China, Mexico, central Japan, and California.
Cupressus is one of several genera of evergreen conifers within the family Cupressaceae that have the common name cypress; for the others, see cypress. It is considered a polyphyletic group. Based on genetic and morphological analysis, the genus Cupressus is found in the subfamily Cupressoideae. The common name "cypress" comes via the Old French cipres from the Latin cyparissus, which is the latinisation of the Greek κυπάρισσος (kypárissos).
Tsuga is a genus of conifers in the subfamily Abietoideae of Pinaceae, the pine family. The English-language common name "hemlock" arose from a perceived similarity in the smell of its crushed foliage to that of the unrelated plant poison hemlock. Unlike the latter, Tsuga species are not poisonous.
Sciadopitys verticillata, the kōyamaki or Japanese umbrella-pine, is a unique conifer endemic to Japan. It is the sole living member of the family Sciadopityaceae and genus Sciadopitys, a living fossil with no close relatives. The oldest fossils of Sciadopitys are from the Late Cretaceous of Japan, and the genus was widespread in Laurasia during most of the Cenozoic, especially in Europe until the Pliocene. An extinct European relative of this species may have been the primary producer of Baltic amber.
Podocarpaceae is a large family of mainly Southern Hemisphere conifers, known in English as podocarps, comprising about 156 species of evergreen trees and shrubs. It contains 19 genera if Phyllocladus is included and Manoao and Sundacarpus are recognized. The family achieved its maximum diversity in the Cenozoic, making the Podocarpaceae family one of the most diverse in the southern hemisphere.
Phyllocladus, the celery pines, is a small genus of conifers, now usually placed in the family Podocarpaceae.Species occur mainly in New Zealand, Tasmania, and Malesia in the Southern Hemisphere, though P. hypophyllus ranges into the Philippines, a short way north of the equator.
Calocedrus, the incense cedar, is a genus of coniferous trees in the cypress family Cupressaceae first described as a genus in 1873. Three species are native to eastern Asia and one to western North America.
Podocarpus is a genus of conifers, the most numerous and widely distributed of the podocarp family, the Podocarpaceae. The name comes from Greek πούς + καρπός. Podocarpus species are evergreen shrubs or trees, usually from 1 to 25 m tall, known to reach 40 m (130 ft) at times. The cones have two to five fused cone scales, which form a fleshy, berry-like, brightly coloured receptacle at maturity. The fleshy cones attract birds, which then eat the cones and disperse the seeds in their droppings. About 97 to 107 species are placed in the genus depending on the circumscription of the species.
Nageia is a genus of conifers belonging to the podocarp family Podocarpaceae. Nageia includes evergreen shrubs and trees, from one to 54 meters in height. A 2009 treatment of the genus recognized five species. Some authors consider Nageia formosensis to be a separate species from Nageia nagi, thus recognizing six species. The podocarp genera have been reshuffled by various botanists. Most recently, several species formerly classed as Nageia were moved to the new genus Retrophyllum, while Nageia falcata and Nageia mannii were moved to the new genus Afrocarpus.
Afrocarpus is a genus of conifer of the family Podocarpaceae. Two to six species are recognized. They are evergreen trees native to Africa. Afrocarpus was designated a genus in 1989, when several species formerly classified in Podocarpus and Nageia were reclassified.
Prumnopitys is a genus of conifers belonging to the family Podocarpaceae. The nine recognized species of Prumnopitys are densely branched, dioecious evergreen trees up to 40 metres in height.
Actinostrobus is a genus of coniferous trees in the Cupressaceae. Common names include cypress, sandplain-cypress and cypress-pine, the last of these shared by the closely related genus Callitris.
Athrotaxis is a genus of two to three species of conifers in the cypress family, Cupressaceae. The genus is endemic to western Tasmania, where they grow in high-elevation temperate rainforests.
Amentotaxus is a genus of conifers (catkin-yews) comprising five species, treated in either the Cephalotaxaceae, or in the Taxaceae when that family is considered in a broad sense. The genus is endemic to subtropical Southeast Asia, from Taiwan west across southern China to Assam in the eastern Himalaya, and south to Vietnam. The species are evergreen shrubs and small trees reaching 2–15 m tall.
Dacrydium guillauminii, commonly known as cat-tail Rimu or swamp Dacrydium, is a species of conifer in the family Podocarpaceae. It is found only in New Caledonia. It is a slow growing shrub or small tree with roots that grow in water, and reaches a height between 1 and 2 metres.
Nageia wallichiana is a species of conifer in the family Podocarpaceae. It is a tree 10–54 m high, found in Brunei, Cambodia, China, India, Indonesia, Laos, Malaysia, Myanmar, Thailand, and Vietnam. Nageia wallichiana is the most widely distributed species among the seven species in the genus Nageia. If the land areas of China and Japan are excluded, its distribution nearly coincides with that of the genus and includes both the western outliers in India and the easternmost part on Normanby Island. It is one of the most extensive conifer ranges recognized and is similar to Dacrycarpus imbricatus and Podocarpus neriifolius.
Retrophyllum rospigliosii is a species of conifer in the family Podocarpaceae. It is a large evergreen tree native to the montane rainforests of Venezuela, Colombia, Peru, Ecuador and Bolivia in South America.
Retrophyllum vitiense is a species of conifer in the family Podocarpaceae. It is a large evergreen rainforest emergent tree native to Fiji, Vanuatu, and the Santa Cruz Islands.
