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Ahnetia conradii
Ahnetia conradii Decombeix, Galtier Rev. Palaeobot. Palynol., 2017, 237(10.1016/j.revpalbo.2016.11.003): 72. 23 Nov 2016
- Name
- Ahnetia conradii
- Rank
- Species
- Generic Name
- [Genus] Ahnetia
- 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
- Fossil Status
- stems
- Stratigraphy
- Tournaisian
- Location
- Hassi Ti-n-Etenaï, Central Ahnet region, Algeria
- Paleoregion
- Gondwana (N Africa)
Data for Holotypus
- Repository
- Université de Montpellier, Montpellier, France
- Repository Number
- UM ALG-JC874
- Diagnosis
- Stem with a circular eustele about 20 mm wide,
composed of about 13 axial strands and incipient leaf traces. Primary
xylem strands peri-medullar, separated from the secondary xylem by
several layers of parenchyma cells. Distance between strands up to
6mm. Primary xylem strands small, typically less than 200 μm in diameter
and usually consisting of a few tracheids. Pith of polygonal parenchyma
cells and about 20–60 sclerotic nests up to 2 mm in diameter
and composed of thick-walled cells of similar dimension than the pith
parenchyma cells. Tracheids of secondary xylem rectangular to polygonal,
with average diameter equal to slightly larger than the metaxylem
tracheids. Rays up to five cells wide, expanded in the innermost part
of secondary xylem, 10–20 cells in height, rarely up to 50. Ray parenchyma
cells procumbent. Secondary phloem with axial elements of parenchyma,
ray cells, probable sieve cells, and fibers. Fibers arranged in
tangential layers up to nine cells thick. Proliferation of axial parenchyma
cells and enlargement of rays in old secondary phloem. Departing leaf
traces about twice the size of the largest strands, dividing in the cortex
in two bundles less than 1 mm wide.
