Trochodendraceae Temporal range: | |
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Trochodendron aralioides | |
Scientific classification | |
Kingdom: | Plantae |
Clade: | Tracheophytes |
Clade: | Angiosperms |
Clade: | Eudicots |
Order: | Trochodendrales Takhtajan ex Cronquist |
Family: | Trochodendraceae Eichler |
Genera | |
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Trochodendraceae is the only family of flowering plants in the order Trochodendrales. It comprises two extant genera, each with a single species [1] along with up to five additional extinct genera and a number of extinct species. [2] The living species are native to south east Asia. The two living species (Tetracentron sinense and Trochodendron aralioides) both have secondary xylem without vessel elements, which is quite rare in angiosperms. As the vessel-free wood suggests primitiveness, these two species have attracted much taxonomic attention.
This section may be too technical for most readers to understand.(October 2020) |
Tetracentron and Trochodendron are deciduous or evergreen trees, which grow to between 20–30 m (66–98 ft) tall, with Trochodendron sometimes sporting umbrella-shaped branches.
Pollination is probably myriophyllous, even though Tetracentron shows a clear anemophilous syndrome. The pulverulent seeds are dispersed by the wind (anemochory). Trochodendron is present in both protandrous and protogynous forms that are self-compatible.
The plants are found in wooded formations, Trochodendron between 300 m and 2.700 m above sea level and Tetracentron between 1.100 m and 3.600 m above sea level.
Flavonoids (quercetin and kaempferol) and proanthocyanidins (cyanidin and delphinidin) are present. Epicuticular waxes are basically composed of nonacosan-10-ol.[ citation needed ] Tetracentron contains chalcones or dihydrochalcones. Trochodendron contains myricetin. Ellagic acid is absent.
Trochodendron and the fossil genus Eotrochion are known from the Paleocene of Wyoming, which constitute the oldest records of the family. [2]
A diverse assemblage of trochodendraceous species have been described from the Eocene OKanagan Highlands in British Columbia and Northeastern Washington. The monotypic genera Paraconcavistylon and Pentacentron are accompanied by Tetracentron hopkinsii and the Trochodendron infructescence morphospecies Tr. drachukii plus the foliage morphospecies Tr. nastae . [3] [2]
The fruit and wood genus Nordenskioeldia , along with the associated leaf morphogenus Zizyphoides have been considered part of Trochodendraceae, though phylogenetic analysis by Manchester et al (2020) suggested they might be better placed as a basal stem lineage in the Trochodendrales, rather than as a crown group member of the family Trochodendraceae. [2]
The Trocodendraceae are a group of flowering plants that include the clade Eudicotyledoneae. In previous systems they have been related with the Cercidiphyllaceae and the Eupteleaceae, with which they share some characteristics that can be considered symplesiomorphic or convergent and that have been excluded from the order Trochodendrales because of molecular data leaving the Trocodendraceae isolated. Based on molecular and morphological data, the APW (Angiosperm Phylogeny Website) considers that it constitutes the only family in the Order Trochodendrales (cf. AP-website).
The current classification of Trochodendraceae is the APG IV system published in 2016, which maintains the circumscription of Trochodendraceae used in the APG III system published in October 2009. Unlike the APG and APG II systems, the later systems place the family as the only family in the order Trochodendrales. They also includes Tetracentron , synonymizing Tetracentraceae fully with Trochodenraceae. [4] [5]
The APG II system, of 2003 retained the classification used in the 1998 APG system recognizing Trochodendraceae as a family. APG and APG II did not place the family in an order, leaving it among the basal lineages of the eudicots. Both APG systems accepts this as a family of two modern species, but it does allow the option of separating out the family Tetracentraceae.
This segregation would lead to two families with one species each: Tetracentraceae with Tetracentron sinense and Trochodendraceae with Trochodendron aralioides .
The Cronquist system, of 1981, accepted both Trochodendraceae and Tetracentraceae as families and placed these in the order Trochodendrales, in subclass Hamamelidae, in class Magnoliopsida.
The family includes two living genera with very different morphological characteristics:
Platanaceae, the "plane-tree family", is a family of flowering plants in the order Proteales. The family consists of only a single extant genus Platanus, with twelve known species. The plants are tall trees, native to temperate and subtropical regions of the Northern Hemisphere. The hybrid London plane is widely planted in cities worldwide.
The water-plantains (Alismataceae) are a family of flowering plants, comprising 20 genera and 119 species. The family has a cosmopolitan distribution, with the greatest number of species in temperate regions of the Northern Hemisphere. Most of the species are herbaceous aquatic plants growing in marshes and ponds.
Menispermaceae is a family of flowering plants. The alkaloid tubocurarine, a neuromuscular blocker and the active ingredient in the 'tube curare' form of the dart poison curare, is derived from the South American liana Chondrodendron tomentosum. Several other South American genera belonging to the family have been used to prepare the 'pot' and 'calabash' forms of curare. The family contains 78 genera with some 440 species, which are distributed throughout low-lying tropical areas with some species present in temperate and arid regions.
Parnassiaceae Gray were a family of flowering plants in the eudicot order Celastrales. The family is not recognized in the APG III system of plant classification. When that system was published in 2009, Parnassiaceae were treated as subfamily Parnassioideae of an expanded family Celastraceae.
Illiciaceae A.C.Sm. was a family of flowering plants recognized in a number of systems of plant taxonomy. The Illiciaceae is not recognized as a distinct family by the APG III system of plant taxonomy, the most well accepted system in use today.
The Hernandiaceae are a family of flowering plants (angiosperms) in the order Laurales. Consisting of five genera with about 58 known species, they are distributed over the world's tropical areas, some of them widely distributed in coastal areas, but they occur from sea level to over 2000 m.
Sabiaceae is a family of flowering plants that were placed in the order Proteales according to the APG IV system. It comprises three genera, Meliosma, Ophiocaryon and Sabia, with 66 known species, native to tropical to warm temperate regions of southern Asia and the Americas. The family has also been called Meliosmaceae Endl., 1841, nom. rej.
Trochodendron is a genus of flowering plants with one living species, Trochodendron aralioides, and six extinct species known from the fossil record. It was often considered the sole genus in the family Trochodendraceae, though botanists now also include the distinct genus Tetracentron in the family.
Tetracentron is a genus of flowering plant with a sole living species being Tetracentron sinense and several extinct species. It was formerly considered the sole genus in the family Tetracentraceae, though it is now included in the family Trochodendraceae together with the genus Trochodendron.
Chloranthaceae is a family of flowering plants (angiosperms), the only family in the order Chloranthales. It is not closely related to any other family of flowering plants, and is among the early-diverging lineages in the angiosperms. They are woody or weakly woody plants occurring in Southeast Asia, the Pacific, Madagascar, Central and South America, and the West Indies. The family consists of four extant genera, totalling about 77 known species according to Christenhusz and Byng in 2016. Some species are used in traditional medicine. The type genus is Chloranthus. The fossil record of the family, mostly represented by pollen such as Clavatipollenites, extends back to the dawn of the history of flowering plants in the Early Cretaceous, and has been found on all continents.
Peridiscaceae is a family of flowering plants in the order Saxifragales. Four genera comprise this family: Medusandra, Soyauxia, Peridiscus, and Whittonia., with a total of 12 known species. It has a disjunct distribution, with Peridiscus occurring in Venezuela and northern Brazil, Whittonia in Guyana, Medusandra in Cameroon, and Soyauxia in tropical West Africa. Whittonia is possibly extinct, being known from only one specimen collected below Kaieteur Falls in Guyana. In 2006, archeologists attempted to rediscover it, however, it proved unsuccessful.
Didymeles is a genus of flowering plants. It is variously treated as the only genus of the family Didymelaceae — or in the family Buxaceae, as in the APG IV system.
Ruppia, also known as the widgeonweeds, ditch grasses or widgeon grass, is the only extant genus in the family Ruppiaceae, with eight known species. These are aquatic plants widespread over much of the world. The genus name honours Heinrich Bernhard Rupp, a German botanist (1688-1719). They are widespread outside of frigid zones and the tropics.
Huerteales is the botanical name for an order of flowering plants. It is one of the 17 orders that make up the large eudicot group known as the rosids in the APG III system of plant classification. Within the rosids, it is one of the orders in Malvidae, a group formerly known as eurosids II and now known informally as the malvids. This is true whether Malvidae is circumscribed broadly to include eight orders as in APG III, or more narrowly to include only four orders. Huerteales consists of four small families, Petenaeaceae, Gerrardinaceae, Tapisciaceae, and Dipentodontaceae.
Tetracentron sinense is a flowering plant native to Asia and the sole living species in the genus Tetracentron. It was formerly considered the sole species in the family Tetracentraceae, though Tetracentron is now included in the family Trochodendraceae together with the genus Trochodendron.
Trochodendron aralioides, sometimes colloquially called wheel tree, is a flowering plant and the sole living species in the genus Trochodendron, which also includes several extinct species. It was also often considered the sole species in the family Trochodendraceae, though botanists now include the distinct genus Tetracentron in the same family. T. aralioides is native to Japan, southern Korea and Taiwan. Growing in lower temperate montane mixed forests in Japan, and broad-leaved evergreen forest in the central mountain ranges and Northern parts of Taiwan.
The Cleomaceae are a small family of flowering plants in the order Brassicales, comprising about 220 species in two genera, Cleome and Cleomella. These genera were previously included in the family Capparaceae, but were raised to a distinct family when DNA evidence suggested the genera included in it are more closely related to the Brassicaceae than they are to the Capparaceae. The APG II system allows for Cleomaceae to be included in Brassicaceae. Cleomaceae includes C3, C3–C4, and C4 photosynthesis species.
Trochodendron nastae is an extinct species of flowering plant in the family Trochodendraceae known from fossil leaves found in the early Eocene Ypresian stage Klondike Mountain Formation deposits of northern Washington state. T. nastae is one of the oldest members of the genus Trochodendron, which includes the living species T. aralioides, native to Japan, southern Korea and Taiwan and the coeval extinct species T. drachukii from the McAbee Fossil Beds near Cache Creek, British Columbia.
Trochodendron drachukii is an extinct species of flowering plants in the family Trochodendraceae known from a fossil fruiting structure found in the early Ypresian age Eocene fossils found in British Columbia, Canada. T. drachukii is one of the oldest members of the genus Trochodendron, which includes the living species T. aralioides, native to Japan, southern Korea and Taiwan and the coeval extinct species T. nastae from Washington state, United States.
Concavistylon is an extinct genus of flowering plant in the family Trochodendraceae comprising a single species Concavistylon kvacekii. The genus is known from fossils found in Middle Miocene deposits of central Oregon. A second species "Concavistylon" wehrii was originally placed in Concavistylon, but subsequently moved to a new genus Paraconcavistylon in 2020.
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