Trochodendron

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Trochodendron
Temporal range: Ypresian to Recent 49.5–0  Ma
Trochodendron aralioides 09072.JPG
Scientific classification OOjs UI icon edit-ltr.svg
Kingdom: Plantae
Clade: Tracheophytes
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.

Contents

Species

Trochodendron is native to Japan, southern Korea, Taiwan and the Ryukyu Islands, with fossils known from North America, Europe, and the Russian Far East. [2]

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.

Fossil record

Among the middle Miocene Sarmatian palynoflora from the Lavanttal Basin Austria researchers have recognized Trochodendron fossil pollen. The sediment containing the Trochodendron fossil pollen had accumulated in a lowland wetland environment with various vegetation units of mixed evergreen/deciduous broadleaved/conifer forests surrounding the wetland basin. Key relatives of the fossil taxa found with Trochodendron pollen are presently confined to humid warm temperate environments, suggesting a subtropical climate during the middle Miocene in Austria. [3]

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<i>Tetracentron</i> Genus of flowering plants in the family Trochodendraceae

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.

<span class="mw-page-title-main">Trochodendraceae</span> Family of flowering plants

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<i>Tetracentron sinense</i> Species of tree

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.

<i>Trochodendron aralioides</i> Species of tree

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.

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<i>Trochodendron nastae</i> Extinct species of flowering plant

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.

<i>Daphniphyllum macropodum</i> Species of tree

Daphniphyllum macropodum is a shrub or small tree found in China, Japan and Korea. Like all species in the genus Daphniphyllum, D. macropodum is dioecious, that is male and female flowers are borne on different plants. The timber is used in China in construction and furniture making. It is grown as an ornamental plant, chiefly for its foliage.

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.

<i>Pentacentron</i> Extinct genus of Trochodendralean plant

Pentacentron is an extinct genus of flowering plant in the family Trochodendraceae, consisting of the single species Pentacentron sternhartae. The genus is known from fossil fruits found in the early Eocene deposits of northern Washington state, United States. P. sternhartae are possibly the fruits belonging to the extinct trochodendraceous leaves Tetracentron hopkinsii.

<i>Tetracentron hopkinsii</i> Extinct species of flowering plant

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.

Trochodendron postnastae is an extinct species of flowering plant in the family Trochodendraceae. The species is known from fossils found in Middle Miocene deposits of central Oregon. T. postnastae are possibly the leaves belonging to the extinct trochodendraceous fruits Trochodendron rosayi.

Acer cascadense is an extinct maple species in the family Sapindaceae described from a series of isolated fossil samaras. The species is known from fossils found in Middle Miocene deposits of central Oregon. It is one of several extinct species placed in the living Acer section Negundo.

Trochodendron rosayi is an extinct species of flowering plant in the family Trochodendraceae. The species is known from fossils found in Middle Miocene deposits of central Oregon. T. rosayi are possibly the fruits belonging to the extinct trochodendraceous leaf species Trochodendron postnastae.

Paraconcavistylon is an extinct genus of flowering plant in the family Trochodendraceae comprises a single species, Paraconcavistylon wehrii. The genus is known from fossil fruits and leaves found in the early Eocene deposits of northern Washington state, United States, and southern British Columbia, Canada. The species was initially described as a member of the related extinct genus Concavistylon as "Concavistylon" wehrii, but subsequently moved to the new genus Paraconcavistylon in 2020 after additional study.

References

  1. Manchester, S. R.; Kvaček, Z.; Judd, W. S. (2020). "Morphology, anatomy, phylogenetics and distribution of fossil and extant Trochodendraceae in the Northern Hemisphere". Botanical Journal of the Linnean Society. 195 (3): 467–484. doi: 10.1093/botlinnean/boaa046 .
  2. 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. S2CID   45399415.
  3. Grímsson, Friđgeir; Meller, Barbara; Bouchal, Johannes M.; Zetter, Reinhard (2015). "Combined LM and SEM study of the middle Miocene (Sarmatian) palynoflora from the Lavanttal Basin, Austria: part III. Magnoliophyta 1 – Magnoliales to Fabales". Grana. 54 (2): 85–128. Bibcode:2015Grana..54...85G. doi:10.1080/00173134.2015.1007081. S2CID   216591875.