Tetracentron sinense | |
---|---|
Tetracentron sinense, leaves and flowers | |
Scientific classification | |
Kingdom: | Plantae |
Clade: | Tracheophytes |
Clade: | Angiosperms |
Clade: | Eudicots |
Order: | Trochodendrales |
Family: | Trochodendraceae |
Genus: | Tetracentron |
Species: | T. sinense |
Binomial name | |
Tetracentron sinense | |
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 .
It is native to southern China, northern Vietnam and the eastern Himalaya (eastern Nepal, Bhutan, Northeast India, and northern Myanmar), where it grows at altitudes of 1,100–3,500 m (3,600–11,500 ft) along streams and forest margins in broad-leaved evergreen and mixed evergreen-deciduous forests. [1]
It is a tree growing to 20–40 m (66–131 ft) tall. The leaves are deciduous (the Flora of China reporting it as evergreen is an error), borne singly at the apex of short spur shoots, each leaf dark green, broad heart-shaped, 5–13 cm (2.0–5.1 in) long and 4–10 cm (1.6–3.9 in) broad, with a rugose surface and a serrated margin. The spur shoots bear one leaf each year, slowly lengthening with each subsequent year.
The flowers are inconspicuous, yellowish green, without petals, produced on slender catkins 10–15 cm (3.9–5.9 in) long; each flower is 1–2 mm (0.039–0.079 in) diameter. The fruit is a follicle 2–5 mm (0.079–0.197 in) diameter, containing 4–6 seeds.
Tetracentron and Trochodendron share the very unusual feature of lacking vessel elements in the wood, something not typical in angiosperms. This has long been considered a very primitive character, resulting in the classification of these two genera in a basal position in the angiosperms; however, molecular phylogenetics research by the Angiosperm Phylogeny Group and others has shown that these two genera are not basal angiosperms, but related basal eudicots. [2] [3] This suggests that the absence of vessel elements in this group is a secondarily evolved character, not a primitive one.
The dicotyledons, also known as dicots, are one of the two groups into which all the flowering plants (angiosperms) were formerly divided. The name refers to one of the typical characteristics of the group: namely, that the seed has two embryonic leaves or cotyledons. There are around 200,000 species within this group. The other group of flowering plants were called monocotyledons, typically each having one cotyledon. Historically, these two groups formed the two divisions of the flowering plants.
Liriodendron is a genus of two species of characteristically large trees, deciduous over most of their populations, in the magnolia family (Magnoliaceae).
The Buxales are a small order of eudicot flowering plants, recognized by the APG IV system of 2016. The order includes the family Buxaceae; the families Didymelaceae and Haptanthaceae may also be recognized or may be included in the Buxaceae. Many members of the order are evergreen shrubs or trees, although some are herbaceous perennials. They have separate "male" (staminate) and "female" (carpellate) flowers, mostly on the same plant. Some species are of economic importance either for the wood they produce or as ornamental plants.
Drosophyllum is a genus of carnivorous plants containing the single species Drosophyllum lusitanicum, commonly known as Portuguese sundew or dewy pine. In appearance, it is similar to the related genus Drosera, and to the much more distantly related Byblis.
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.
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.
Trochodendraceae is the only family of flowering plants in the order Trochodendrales. It comprises two extant genera, each with a single species along with up to five additional extinct genera and a number of extinct species. The living species are native to south east Asia. The two living species 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.
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.
Scheuchzeria palustris, is a flowering plant in the family Scheuchzeriaceae, in which there is only one species and Scheuchzeria is the only genus. In the APG II system it is placed in the order Alismatales of the monocots.
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.
Aphloia is a genus of flowering plants that contains a single species, Aphloia theiformis, the sole species of the monogeneric family Aphloiaceae. It is a species of evergreen shrubs or small trees occurring in East Africa, Madagascar, the Mascarene Islands and the Seychelles.
Cercidiphyllum japonicum, known as the katsura, is a species of flowering tree in the family Cercidiphyllaceae native to China and Japan. It is sometimes called caramel tree for the light caramel smell it emits during leaf fall.
Oreocallis is a South American plant genus in the family Proteaceae. There is only one species, Oreocallis grandiflora, which is native to mountainous regions in Peru and Ecuador.
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.
Eucommia is a genus of small trees now native to China, with a fossil record that shows a much wider distribution. The single living species, Eucommia ulmoides, is near threatened in the wild, but is widely cultivated in China for its bark, and is highly valued in herbology such as traditional Chinese medicine.
Borthwickia is genus of flowering plants, containing one species, Borthwickia trifoliata from Yunnan, China and Myanmar. The common name in Chinese is 节蒴木. It is a shrub or small tree with evergreen trifoliate leaves, whitish flowers clustered at the tip of the branches, with many stamens, and thin, knobbly, drooping fruits with many small red seeds.
Cleistanthus sumatranus is an accepted name of a tree species in the genus Cleistanthus. No subspecies are listed in the Catalogue of Life.
Tetracentron hopkinsii is an extinct species of flowering plant in the family Trochodendraceae. The species is known from fossil leaves found in the early Eocene deposits of northern Washington state, United States and south Central British Columbia. The species was first described from fossil leaves found in the Allenby Formation. T. hopkinsii are possibly the leaves belonging to the extinct trochodendraceous fruits Pentacentron sternhartae.