Trochodendron

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Trochodendron
Temporal range: Ypresian to Recent 49.5–0Ma
Trochodendron aralioides 2.jpg
Scientific classification e
Kingdom: Plantae
Clade: Angiosperms
Clade: Eudicots
Order: Trochodendrales
Family: Trochodendraceae
Genus: Trochodendron
Siebold & Zucc., 1838
Species

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 Trochodendraceae.

Species[edit]

Trochodendron is native to Japan, southern Korea, Taiwan and the Ryukyu Islands, with fossils know from North America and Europe.[1]

Trochodendron aralioides is an evergreen tree or large shrub growing to 20 m tall. Trochodendron and Tetracentron lack vessel elements in their wood, a quite unusual feature 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, genetic research by the Angiosperm Phylogeny Group has shown it to be in a less basal position (early in the eudicots), suggesting the absence of vessel elements in these two genera is a secondarily evolved character, not a primitive one.

References[edit]

  1. ^ Pigg, K.B.; Wehr, W.C.; Ickert-Bond, S.M. (2001). "Trochodendron and Nordenskioldia (Trochodendraceae) from the Middle Eocene of Washington State, U.S.A.". International Journal of Plant Sciences 162 (5): 1187–1198. doi:10.1086/321927. 

External links[edit]