Gastonispermum

Name

Gastonispermum

Rank

Genus

Authors (Pub.)

Friis E. M. Crane P. R. Pedersen K. R.  

Publication

Extinct taxa of exotestal seeds close to Austrobaileyales and Nymphaeales from the Early Cretaceous of Portugal [2018/8]

Journal

Fossil Imprint

Volume

74

Issue

1-2

Page number

138

Year

2018

Parent Taxon

[Class] Magnoliopsida

Fossil Status

seeds

Type

Gastonispermum portugallicum

Diagnosis

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.