Ahnetia

Name

Ahnetia

Rank

Genus

Authors (Pub.)

Decombeix A.-L. Galtier J.  

Publication

Ahnetia, a new lignophyte stem from the Lower Carboniferous of southern Algeria [2016/11]

Journal

Review of Palaeobotany and Palynology

Annee/Jahrgang

2017

Volume

237

Issue

10.1016/j.revpalbo.2016.11.003

Page number

72

Year

2016

Parent Taxon

[Subclass] Pityidae

Fossil Status

stems

Type

Ahnetia conradii

Diagnosis

Stem with primary and secondary vascular tissues and primary cortex. Eustele consisting of small discrete axial strands of primary xylemat the periphery of a broad circular pithwith sclerotic nests. Ratio of primary xylem diameter to stem diameter high (about 1:1.7). Axial primary xylem strands widely spaced, composed of a few tracheids, and separated fromthe secondary xylemby several layers of parenchyma cells. Leaves arranged in a complex spiral. Leaf emission starting with two divisions of a primary xylem strand and formation of an arc-shaped group of three strands that moves towards the secondary xylem. One of these strands emitted as a simple leaf trace with one protoxylem strand. No evidence of a sympodial nature of the vascular system. Leaf trace dividing in two in the cortex. Secondary xylem tracheids with multiseriate bordered pits on radial walls. Rays uni- to multiseriate, not high. Secondary phloem present, including fibers arranged in tangential layers several cells in thickness. Evidence of periderm formation within the secondary phloem. Cortex consisting of parenchyma with sclerotic nests.