''Tetracentron sinense'' is a

flowering plant Flowering plants are plants that bear flowers and fruits, and form the clade Angiospermae (). The term angiosperm is derived from the Ancient Greek, Greek words (; 'container, vessel') and (; 'seed'), meaning that the seeds are enclosed with ...

native to Asia and the sole living species in the genus ''

Tetracentron ''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 fami ...

''. It was formerly considered the sole species in the family

Tetracentraceae 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 specie ...

, though ''Tetracentron'' is now included in the family

Trochodendraceae 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 specie ...

together with the genus ''

Trochodendron ''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 ...

''.

Range and habitat

It is native to southern

China China, officially the People's Republic of China (PRC), is a country in East Asia. With population of China, a population exceeding 1.4 billion, it is the list of countries by population (United Nations), second-most populous country after ...

, northern

Vietnam Vietnam, officially the Socialist Republic of Vietnam (SRV), is a country at the eastern edge of mainland Southeast Asia, with an area of about and a population of over 100 million, making it the world's List of countries and depende ...

and the eastern

Himalaya The Himalayas, or Himalaya ( ), is a mountain range in Asia, separating the plains of the Indian subcontinent from the Tibetan Plateau. The range has some of the Earth's highest peaks, including the highest, Mount Everest. More than 100 pea ...

(eastern

Nepal Nepal, officially the Federal Democratic Republic of Nepal, is a landlocked country in South Asia. It is mainly situated in the Himalayas, but also includes parts of the Indo-Gangetic Plain. It borders the Tibet Autonomous Region of China Ch ...

Bhutan Bhutan, officially the Kingdom of Bhutan, is a landlocked country in South Asia, in the Eastern Himalayas between China to the north and northwest and India to the south and southeast. With a population of over 727,145 and a territory of , ...

Northeast India Northeast India, officially the North Eastern Region (NER), is the easternmost region of India representing both a geographic and political Administrative divisions of India, administrative division of the country. It comprises eight States and ...

, and northern

Myanmar Myanmar, officially the Republic of the Union of Myanmar; and also referred to as Burma (the official English name until 1989), is a country in northwest Southeast Asia. It is the largest country by area in Mainland Southeast Asia and has ...

), where it grows at altitudes of along streams and forest margins in broad-leaved evergreen and mixed evergreen-deciduous forests.

Morphology

It is a

tree In botany, a tree is a perennial plant with an elongated stem, or trunk, usually supporting branches and leaves. In some usages, the definition of a tree may be narrower, e.g., including only woody plants with secondary growth, only ...

growing to tall. The

leaves A leaf (: leaves) is a principal appendage of the stem of a vascular plant, usually borne laterally above ground and specialized for photosynthesis. Leaves are collectively called foliage, as in "autumn foliage", while the leaves, stem, ...

are

deciduous In the fields of horticulture and botany, the term deciduous () means "falling off at maturity" and "tending to fall off", in reference to trees and shrubs that seasonally shed Leaf, leaves, usually in the autumn; to the shedding of petals, aft ...

(the ''Flora of China'' reporting it as evergreen is an error), borne singly at the apex of short

spur shoot In botany, a plant shoot consists of any plant stem together with its appendages like leaves, lateral buds, flowering stems, and flower buds. The new growth from seed germination that grows upward is a shoot where leaves will develop. In the sp ...

s, each leaf dark green, broad heart-shaped, long and broad, with a rugose surface and a serrated margin. The spur shoots bear one leaf each year, slowly lengthening with each subsequent year. The

flower Flowers, also known as blooms and blossoms, are the reproductive structures of flowering plants ( angiosperms). Typically, they are structured in four circular levels, called whorls, around the end of a stalk. These whorls include: calyx, m ...

s are inconspicuous, yellowish green, without petals, produced on slender

catkin A catkin or ament is a slim, cylindrical flower cluster (a spike), with inconspicuous or no petals, usually wind- pollinated ( anemophilous) but sometimes insect-pollinated (as in '' Salix''). It contains many, usually unisexual flowers, arra ...

s long; each flower is diameter. The

fruit In botany, a fruit is the seed-bearing structure in flowering plants (angiosperms) that is formed from the ovary after flowering. Fruits are the means by which angiosperms disseminate their seeds. Edible fruits in particular have long propaga ...

is a follicle diameter, containing 4–6

seed In botany, a seed is a plant structure containing an embryo and stored nutrients in a protective coat called a ''testa''. More generally, the term "seed" means anything that can be Sowing, sown, which may include seed and husk or tuber. Seeds ...

s. ''Tetracentron'' and ''Trochodendron'' were described to share the very unusual feature of lacking

vessel element A vessel element or vessel member (also called a xylem vessel) is one of the cell types found in xylem, the water conducting tissue of plants. Vessel elements are found in most angiosperms (flowering plants) and in some gymnosperms such as cyca ...

s in the

wood Wood is a structural tissue/material found as xylem in the stems and roots of trees and other woody plants. It is an organic materiala natural composite of cellulosic fibers that are strong in tension and embedded in a matrix of lignin t ...

, 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 Molecular phylogenetics () is the branch of phylogeny that analyzes genetic, hereditary molecular differences, predominantly in DNA sequences, to gain information on an organism's evolutionary relationships. From these analyses, it is possible to ...

research by the

Angiosperm Phylogeny Group The Angiosperm Phylogeny Group (APG) is an informal international group of systematic botanists who collaborate to establish a consensus on the taxonomy of flowering plants (angiosperms) that reflects new knowledge about plant relationships disc ...

and others, has shown that these two genera are not

basal angiosperms The basal angiosperms are the flowering plants which diverged from the lineage leading to most flowering plants. In particular, the most basal angiosperms were called the ANITA grade, which is made up of ''Amborella'' (a single species of shrub f ...

, but related basal eudicots. This suggested that the absence of vessel elements in this group is a secondarily evolved character, not a primitive one. However, a study in 2020 reported that ''T. sinense'' has vessel elements and it also has the key genes that regulate vessel formation. image:Tetracentron sinense - Arbre-2.jpg, Branches image:Tetracentron sinense - Feuilles et fleurs-2.jpg, Leaves and flowers image:Tetracentron sinense - Feuilles et fleurs-3.jpg, Leaves and flowers image:Tetracentron sinense - Feuilles et fleurs.jpg, Leaves and flowers image:Tetracentron sinense - Couleur automnale.jpg, Fall color image:Tetracentron sinense - Jeunes graines-2.jpg, Young seeds image:Tetracentron sinense - Jeunes graines.jpg, Young seeds

References

External links

*Flora of China
''Tetracentron''
an
Tetracentraceae
{{Taxonbar, from=Q1418111 Trochodendrales Trees of Bhutan Trees of China Flora of East Himalaya Trees of Myanmar Trees of Nepal Trees of Vietnam Taxa named by Daniel Oliver