Silutanispermum

Name

Silutanispermum

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

149

Year

2018

Parent Taxon

[Class] Magnoliopsida

Fossil Status

seeds

Type

Silutanispermum kvacekiorum

Diagnosis

Isolated seeds occurring singly. Seeds small, anatropous, bitegmic and exotestal. Seeds bilaterally symmetrical with dorsiventral plane of symmetry. Seed surface smooth without longitudinal ridges. Raphe indistinct externally. Hilum and micropyle separated by a narrow zone of testal sclerenchyma. Hilar scar small, triangular without a rim. Micropyle formed by the inner integument (tegmen) and marked on the seed surface by a transverse, slightly wavy slit through the outer integument (testa) adjacent to hilar scar. Testa formed from an outer layer (exotesta) of palisade-shaped sclerenchyma cells and an inner thick layer of large parenchyma cells (mesotesta/endotesta), that is particularly well-developed close to hilum. Palisade-shaped cells of exotesta with unevenly thickened walls that are thick towards the outside, slightly thinner towards the inside, but with an almost straight lumen. Anticlinal walls of palisadeshaped sclerenchyma strongly undulate towards the inside and towards the outside, resulting in stellate-undulate facets and a jigsaw puzzle-like pattern on the seed surface except over the raphe where the cell walls are straight and facets polygonal. Tegmen thin. Embryo tiny with two rudimentary cotyledons.