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Sennicaulis hippocrepiformis
Sennicaulis hippocrepiformis D. Edwards Rev. Palaeobot. Palynol., 32(2-3): 225. 8 Apr 1981
- Name
- Sennicaulis hippocrepiformis
- Rank
- Species
- Generic Name
- [Genus] Sennicaulis
- Authors (Pub.)
- Edwards D.
- Publication
- Studies on Lower Devonian petrifactions from Britain 2 [1981/4]
- Journal
- Review of Palaeobotany and Palynology
- Volume
- 32
- Issue
- 2-3
- Page number
- 225
- Year
- 1981
- Fossil Status
- stems
- Stratigraphy
- Pragian
- Strat. comment
- Senni Beds, Breconian Stage
- Location
- Brecon Beacons Quarry, abandoned roadside quarry near Storey Arms, on the A470 road between Brecon and Merthyr, approximately 12 km south of Brecon, Powys, U.K.
- Paleoregion
- Laurussia (Avalonia)
Data for Holotypus
- Repository
- Natural History Museum, London, U.K.
- Repository Number
- Sections V60352-V60386
- Diagnosis
- Axes up to 6.0 mm maximum diameter, ? smooth; branching pattern unknown. Xylem strand terete, sometimes slightly compressed, 0.9--0.2 X 0.8--0.15 mm in cross-sections and occupying 1/3 to 1/7 diameter of complete axis. Centrarch; protoxylem tracheids probably annular with average diameter 12 pm; metaxylem tracheids with helical and annular secondary thickenings up to 50 um diameter (majority between 20 and 35 pm). Secondary thickenings 4--12 pm thick, variably spaced in the narrower tracheids, more regular in the wider metaxylem tracheids where majority 1--2 bar widths apart. Extraxylary zone up to 30 pm wide consisting of up to three layers of cells, usually crushed and consisting of two types of cells; inner layer square to rectangular in longitudinal section, outer with narrow elongate cells. Outer cortex composed of up to five layers of thick-walled (ca. 5 t~m) cells, more or less isodiametric in cross-section, but decreasing in diameter and length towards outside; range in width 25--100 pm (average 49.6 um), up to 450 pm long.
