Pachytheca
| Pachytheca | ||||||||||
|---|---|---|---|---|---|---|---|---|---|---|
| Temporal occurrence | ||||||||||
| Upper Silurian to Middle Devonian | ||||||||||
| Systematics | ||||||||||
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| Scientific name | ||||||||||
| Pachytheca | ||||||||||
Pachytheca is a genus of fossils that is oftendiscussedas a possible early land plant . It comes from the upper Silurian to middle Devonian.
The specimens are rather small with 0.1 to 0.6 centimeters in diameter. They are spherical and consist of two different zones. The inner zone, called the medulla, consists of tightly packed, intertwined tubes. The outer zone, called the bark, consists of radially arranged tubes. Between the cortex and medulla there is a narrow zone in which the tubes alternate between random and orderly arrangement. In some specimens there is a channel connecting the medulla to the outside.
One interpretation of Pachytheca is as the unit of propagation (cystocarp) of Prototaxites . However, no organically related finds are known. Another interpretation sees Pachytheca as the youthful form of Parka decipiens .
supporting documents
- 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 . P. 183f.