Protopitys
| Protopitys | ||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Temporal occurrence | ||||||||||||
| Lower Carboniferous ( Tournaisium ) | ||||||||||||
| Systematics | ||||||||||||
|
||||||||||||
| Scientific name of the order | ||||||||||||
| Protopityales | ||||||||||||
| J. Walton | ||||||||||||
| Scientific name of the genus | ||||||||||||
| Protopitys | ||||||||||||
| J. Walton |
Protopitys is an extinct genus of plants. It is the only genus of the order Protopityales and is part of the progymnosperms . The representatives are relatively poorly known.
features
The stems show an elliptical in cross-section Mark , at its two ends a endarches primary vascular bundle lies. The tracheids located in the secondary xylem have ladder-shaped pits in Protopitys buchiana , in Protopitys scotica the round courtyard pits are in several rows (multiseriat). By Protopitys scotica known roots are diarch and have no secondary xylem.
Leaves or other photosynthetically active organs are not known.
The sporangia are terminally attached to double dichotomous branches. The sporangia themselves are elongated and opened lengthways. The spores are triple and between 75 and 355 micrometers in size. They have an extra-exinal skin that may have been a sac. The large size variance is interpreted as an indication of possible heterosporia .
Systematics
The Protopityales are placed among the progymnosperms due to their gymnosperm wood and their mode of reproduction. Only the two species Protopitys buchiana and Protopitys scotica are known.
supporting documents
- Thomas N. Taylor, Edith L. Taylor: The Biology and Evolution of Fossil Plants , p. 458. Prentice Hall, Englewood Cliffs 1993. ISBN 0-13-651589-4