Cephalotaxus Temporal range: | |
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Cephalotaxus harringtonii | |
Scientific classification | |
Kingdom: | Plantae |
Clade: | Tracheophytes |
Clade: | Gymnospermae |
Division: | Pinophyta |
Class: | Pinopsida |
Order: | Cupressales |
Family: | Taxaceae |
Genus: | Cephalotaxus Siebold & Zucc. ex Endl. |
Type species | |
Cephalotaxus pedunculata | |
Species | |
Cephalotaxus, commonly called plum yew or cowtail pine, is a genus of conifers comprising 11 species, either considered the only member of the family Cephalotaxaceae, or in the Taxaceae when that family is considered in a broad sense. [1] [2] The genus is endemic to eastern Asia, though fossil evidence shows it had a wider Northern Hemisphere distribution in the past. [1] The species are evergreen shrubs and small trees reaching 1.0–10 metres (3–33 ft) (rarely to 20 metres (66 ft)) tall.
The leaves are spirally arranged on the shoots, but twisted at the base to lie in two flat ranks (except on erect leading shoots); they are linear, 4–12 centimetres (1+1⁄2–4+3⁄4 in) long and 3–4 millimetres (1⁄8–5⁄32 in) broad, soft in texture, with a blunt tip; this helps distinguish them from the related genus Torreya , which has spine-tipped leaves. [2]
The species can be either monoecious or dioecious; when monoecious, the male and female cones are often on different branches. The male (pollen) cones are 5–8 millimetres (13⁄64–5⁄16 in) long, grouped in lines along the underside of a shoot. The female (seed) cones are single or grouped two to 15 together on short stems; minute at first, they mature in about 18 months to a drupe-like structure with the single large nut-like seed 1.5–4 centimetres (5⁄8–1+5⁄8 in) long surrounded by a fleshy covering, green to purple at full maturity. Natural dispersal is thought to be aided by squirrels which bury the seeds for a winter food source; any seeds left uneaten are then able to germinate. [2]
Cephalotaxus species produce cephalotaxine, an alkaloid. Parry et al 1980 provides evidence that cephalotaxine is a phenylethylisoquinoline. However, they also find this genus to be unable to incorporate cinnamic acid into cephalotaxine, and incorporation of cinnamic acid is usually a step in phenylethylisoquinoline syntheses, throwing the phenylethylisoquinoline theory in to question. [3]
Molecular studies place Cephalotaxus as the most basal member of the Taxaceae, having a very ancient divergence from them during the late Triassic. [4] Historically, it was placed as the only member of the family Cephalotaxaceae, due to strong morphological differences from other members of Taxaceae, [5] but major authorities consider the family synonymous with Taxaceae. [6] [7]
The taxonomy of Cephalotaxus is difficult, because the species have been defined using characteristics that intergrade with each other, such as the length and shape of needles, bark, and stomatal band color. Cephalotaxus species have often been separated geographically rather than morphologically. [8]
Phylogeny of Cephalotaxus [9] [10] | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||
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The oldest fossils of Cephalotaxus are known from the Eocene of Heilongjiang in northeast China and the Messel Pit of Germany. The youngest fossils of Cephalotaxus in Europe date to the Pliocene, and remains are also known from the Miocene of western North America. [11] [12]
Ginkgoales are a gymnosperm order containing only one extant species: Ginkgo biloba, the ginkgo tree. The order has a long fossil record extending back to the Early Permian around 300 million years ago from fossils found worldwide.
Taxaceae, commonly called the yew family, is a coniferous family which includes six extant and two extinct genera, and about 30 species of plants, or in older interpretations three genera and 7 to 12 species.
Chamaecyparis, common names cypress or false cypress, is a genus of conifers in the cypress family Cupressaceae, native to eastern Asia and to the western and eastern margins of the United States. The name is derived from the Greek khamai (χαμαί), meaning "on the earth", and kuparissos (κυπάρισσος) for "cypress".
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.
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.
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.
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.
Dacrycarpus is a genus of conifers belonging to the family Podocarpaceae. The genus includes nine species of dioecious evergreen trees and shrubs to 55–60 metres (180–197 ft) in height.
Halocarpus is a genus of conifers of the family Podocarpaceae. The genus includes three closely related species of evergreen trees and shrubs, all endemic to New Zealand.
Lepidothamnus is a genus of conifers belonging to the podocarp family Podocarpaceae. The genus includes three species of dioecious or monoecious evergreen trees and shrubs, and creepers. L. intermedius and L. laxifolius are native to New Zealand. L. fonkii is native to the Magellanic subpolar forests ecoregion of southern Argentina and Chile, where it grows as a low shrub or creeper in moorlands and bogs.
Callitris is a genus of coniferous trees in the Cupressaceae. There are 16 recognized species in the genus, of which 13 are native to Australia and the other three native to New Caledonia. Traditionally, the most widely used common name is cypress-pine, a name shared by some species of the closely related genus Actinostrobus.
Keteleeria is a genus of three species of coniferous trees in the family Pinaceae first described as a genus in 1866.
Libocedrus is a genus of five species of coniferous trees in the cypress family Cupressaceae, native to New Zealand and New Caledonia. The genus is closely related to the South American genera Pilgerodendron and Austrocedrus, and the New Guinean genus Papuacedrus, both of which are included within Libocedrus by some botanists. These genera are rather similar to the Northern Hemisphere genera Calocedrus and Thuja: in earlier days, what is now Calocedrus was sometimes included in Libocedrus. They are much less closely related, as recently confirmed. The generic name means "teardrop cedar", apparently referring to drops of resin.
Torreya is a genus of conifers comprising six or seven species placed in the family Taxaceae, though sometimes formerly placed in Cephalotaxaceae. Four species are native to eastern Asia; the other two are native to North America. They are small to medium-sized evergreen trees reaching 5–20 m, rarely 25 m, tall. Common names include nutmeg yew.
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.
Retrophyllum is a genus of conifers in the family Podocarpaceae. It contains five generally recognized extant species with a disjunct distribution in the Southern Hemisphere, found in Papuasia and also in South America. Retrophyllum are evergreen trees typically occurring in tropical rainforests and cloud forests.
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.
Ceratozamia is a genus of New World cycads in the family Zamiaceae. The genus contains 27 known currently living species and one or two fossil species. Most species are endemic to mountainous areas of Mexico, while few species extend into the mountains of Guatemala, Honduras and Belize. The genus name comes from the Greek ceras, meaning horn, which refers to the paired, spreading horny projections on the male and female sporophylls of all species.
Hesperocyparis is a genus of trees in the family Cupressaceae, containing North American species otherwise assigned to the genus Cupressus. They are found throughout western North America. Only a few species have wide ranges, with most being restricted-range endemics.
It is suggested a late Pliocene age (Reuverian) for this flora. Palynofloras from drill cores in the surroundings of Frankfurt am Main and Hanau also suggests a late Pliocene age. The Pliocene flora of Frankfurt am Main described by Karl Mädler during the first half of the twentieth century is a key flora for the European Pliocene.
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