Schmeissneria
Germany, China
Schmeissneria is an extinct relative of the ginkgo and the only genus of the family Schmeissneriaceae.
Features
Of the other members of the genus Ginkgoales distinguished by the following features: The fertile shoots bear in a spiral arrangement of single or paired cupulae which may be sessile or pedunculated. The seeds are winged to maturity.
The seed-bearing axes are up to 8 cm long and carry up to 45 teardrop-shaped cupulae. Each of them is long and 3.5 mm. At maturity, the seeds are up to 5 mm long.
There shall be set short and long rung. The leaves are undivided and sitting.
Together with Schmeissneria microstachys be pollen organs preslii found the type Stachyopitys and should belong to the same plant.
Dissemination
The genus Schmeissneria is from the Hettangian ( Lower Jurassic ) of Germany and the Middle Jurassic, Callovian probably known of Liaoning in northeastern China.
System
The genus Schmeissneria 1994 positioned for the type species Schmeissneria microstachys by Kirchner and Van Cittert Konijnenburgvan. In 1997, the genus in its own family Schmeissneriaceae was provided. It was interpreted as representative of the Ginkgoales. However, some features, they also near the Gnetophyta.
After the finding of Schmeissneria sinensis in the Haifanggou Formation in Liaoning affinity was discussed among the angiosperms. In this way, the ovules are paired on short stalks along an axis with cupulae. Each of the ovules has a central unit which is surrounded by a sheath with characteristic longitudinal ribs. The top is completely closed by a wall. Each central unit has two compartments that are completely separated by a vertical septum.
Documents
- Zhi- Yan Zhou: An overview of fossil Ginkgoales. Palaeoworld, Vol 18, 2009, pp. 1-22, doi: 10.1016/j.palwor.2009.01.001
- Thomas N. Taylor, Edith L. Taylor, Michael Krings: Paleobotany. The Biology and Evolution of Fossil Plants. Second Edition, Academic Press 2009, ISBN 978-0-12-373972-8. S. 753
- Seed plants
- Spermatophytina
- Extinct plant