Tetracentron sinense

Classification System: APG IV

Superregnum: Eukaryota
Regnum: Plantae
Cladus: Angiosperms
Cladus: Eudicots
Ordo: Trochodendrales

Familia: Trochodendraceae
Genus: Tetracentron
Species: Tetracentron sinense
Name

Tetracentron sinense Oliv.
References

Hooker's Icones Plantarum; or Figures, with brief Descriptive Characters and Remarks of New or Rare Plants 19: t. 1892. 1889
USDA, ARS, Germplasm Resources Information Network. Tetracentron sinense in the Germplasm Resources Information Network (GRIN), U.S. Department of Agriculture Agricultural Research Service. Accessed: 08-Apr-12.

Vernacular names
中文: 水青树

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.

Range and habitat

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]
Morphology

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.

References

Bartholomew, Bruce. "Tetracentron sinense". Flora of China. Retrieved 30 September 2020.
Worberg, Andreas; Quandt, Dietmar; Barniske, Anna-Magdalena; Löhne, Cornelia; Hilu, Khidir W.; Borsch, Thomas (2007). "Phylogeny of basal eudicots: Insights from non-coding and rapidly evolving DNA". Organisms Diversity & Evolution. 7 (1): 55–77. doi:10.1016/j.ode.2006.08.001.
Burleigh, J. Gordon; Hilu, Khidir W.; Soltis, Douglas E. (2009). "Inferring phylogenies with incomplete data sets: a 5-gene, 567-taxon analysis of angiosperms". BMC Evolutionary Biology. 9 (1): 61. doi:10.1186/1471-2148-9-61. PMC 2674047. PMID 19292928.