Leclercqia (plant)
| Leclercqia | ||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|
Leclercqia complexa |
||||||||||||
| Temporal occurrence | ||||||||||||
| Lower Devon to Middle Devon | ||||||||||||
| 416 to 385 million years | ||||||||||||
| Locations | ||||||||||||
|
Australia, North and South America, Europe |
||||||||||||
| Systematics | ||||||||||||
|
||||||||||||
| Scientific name | ||||||||||||
| Leclercqia | ||||||||||||
| HPBanks , Bonamo & Grierson |
Leclercqia is an extinct plant genus from the Devonian and is placed in the order of the Protolepidodendrales , an early group of the club moss plants .
Specimens of Leclercqia complexa are up to 46 cm high and have a diameter of 3.5 to 7 mm. The shoot axes are dichotomous or pseudo monopodial and are covered with 6.5 mm long microphylls . These leaves have two lateral appendages roughly in the middle, which in turn are divided and have pointed ends. The central part is gradually narrowed and bent backwards. The five-pointed leaves are narrow and give the plant an unusual appearance. Leclercqia has ligules .
In some finds, the stele has been preserved as a pyrite stone. The stele is circular in cross section and has up to 18 outer proto xylem points. The metaxylem consists of stair tracheids or the tracheids have oval pits. The stele is surrounded by a narrow, parenchymal cortex . Each leaf is supplied by a single vascular bundle that branches off from a protoxylemic cord of the stele.
The sporangia are located adaxially to the surface of the sporophyll . The sporophylls are practically indistinguishable from the sterile leaves and are distributed over the entire stem axis. The spores are trilet, have a diameter of 60 to 85 µm and are covered with numerous, densely seated spines with a broad base. The numerous finds with only one kind of spores are interpreted as an indication that Leclercqia was homospor .
supporting documents
- Thomas N. Taylor, Edith L. Taylor, Michael Krings: Paleobotany. The Biology and Evolution of Fossil Plants . 2nd Edition. Elsevier / Academic Press, Amsterdam et al. 2009, ISBN 978-0-12-373972-8 , pp. 275–278 ( limited preview in Google Book search).