Genus Gastonispermum Friis, P.R. Crane, K. R. Peders. Foss. Impr., 74(1-2): 138. 31 Aug 2018
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- Authors (Pub.)
- Friis E. M.
Crane P. R.
Pedersen K. R.
- Extinct taxa of exotestal seeds close to Austrobaileyales and Nymphaeales from the Early Cretaceous of Portugal [2018/8]
- Fossil Imprint
- Page number
- Parent Taxon
- [Class] Magnoliopsida
- Fossil Status
- Gastonispermum portugallicum
- Isolated seeds occurring singly. Seeds small, anatropous, bitegmic and exotestal. Seeds bilaterally symmetrical with a dorsiventral plane of symmetry. Seed surface smooth without longitudinal ridges. Raphe distinct, seen externally as a slightly raised rounded ridge that extends from hilum to the chalazal end opposite the micropyle. Hilum and micropyle separated by a narrow zone of sclerenchyma. Hilar scar small, slightly raised without
a hilar rim. Micropyle formed by the inner integument (tegmen) and marked on the seed surface by a Y-shaped slit through the outer integument (testa) adjacent to the hilar scar. Testa formed from an outer layer (exotesta) of
palisade-shaped sclerenchyma cells and an inner thin layer of thin-walled parenchyma cells (mesotesta/endotesta). Palisade-shaped cells of exotesta with evenly thickened anticlinal walls and a straight lumen. Anticlinal walls of
palisade-shaped sclerenchyma strongly undulate toward the inside and toward the outside, resulting in stellate-undulate facets and a jigsaw puzzle-like pattern on the seed surface. Tegmen thin. Embryo tiny with two rudimentary cotyledons.