Pentacentron
| Pentacentron Temporal range:
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|---|---|
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| Holotype infructescence, SR 93-08-02 | |
Scientific classification 
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| Kingdom: | Plantae |
| Clade: | Tracheophytes |
| Clade: | Angiosperms |
| Clade: | Eudicots |
| Order: | Trochodendrales |
| Family: | Trochodendraceae |
| Genus: | †Pentacentron |
| Species: | †P. sternhartae
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| Binomial name | |
| †Pentacentron sternhartae Manchester et al, 2018
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Pentacentron is an
Distribution and paleoenvironment
Pentacentron sternhartae is known from specimens which are recovered from outcrops of the early Eocene,
Taxonomy
The species was described from a
Pe. sternhartae is one of between three and four trochodendraceae species that have been described from the Klondike Mountain Formation. Broadly circumscribed, three other species have been identified at Republic, Paraconcavistylon wehrii, Tetracentron hopkinsii, and Trochodendron nastae. Additionally the species Trochodendron drachukii is known from related Kamloops group shales at the McAbee Fossil Beds near Cache Creek, British Columbia. Manchester et al 2018 noted that Tr. drachukii is likely the fruits of Tr. nastae, while Pe. sternhartae are likely the fruits of Te. hopkinsii.[2] If fossils of the fruits and foliage in attachment are found, that would bring the species count down to three whole plant taxa.[2]
Description
Pentacentron sternhartae fruiting spikes range between 5.8–9.2 cm (2.3–3.6 in) in length with the fruits arranged long the axis in a helical pattern. Each capsule is sessile on the thin raceme. The capsular heads consist of five fruiting chambers, arranged pentagonally around the midline of the 1.3–1.5 mm (0.051–0.059 in) wide head. Growing from the middle area of each chamber is an apically and inwardly curving persistent style, each with an elliptical nectary bulge at its base. Rimming the base of each fruit are Perianth scars creating a raised flange. The fruits opened apically, through separation lines running from just above the styles up to the fruit tip where they met to form a pentagonal star like opening.[2]
References
- ^ doi:10.1139/E04-095.
- ^ S2CID 92201595.
- ^ Wolfe, J.A.; Tanai, T. (1987). "Systematics, Phylogeny, and Distribution of Acer (maples) in the Cenozoic of Western North America". Journal of the Faculty of Science, Hokkaido University. Series 4, Geology and Mineralogy. 22 (1): 1–246.
- ^ Wolfe, J.A.; Wehr, W.C. (1987). "Middle Eocene dicotyledonous plants from Republic, northeastern Washington". United States Geological Survey Bulletin. 1597: 1–25.