Lusitanispermum

Name

Lusitanispermum

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

147

Year

2018

Parent Taxon

[Class] Magnoliopsida

Fossil Status

seeds

Type

Lusitanispermum choffatii

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 close together separated by a narrow zone of testal sclerenchyma. Hilar scar small without a hilar rim. Micropyle formed by the inner integument (tegmen) and marked on the seed surface by a transverse slit through the outer integument (testa) adjacent to the hilar scar. Testa formed from an outer layer (exotesta) of palisadeshaped sclerenchyma cells, and an inner thick layer of large parenchyma cells (mesotesta/endotesta). Palisade-shaped cells of exotesta with unevenly thickened walls that are thick towards the outside, thin towards the inside, and have a conical lumen. Exotesta thick adjacent to the hilum forming a bulging zone that may be two-parted. 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 except over the raphe and around the micropyle where the cell walls are straight and facets polygonal. Tegmen thin. Embryo tiny, with two rudimentary cotyledons.