Reyispermum

Name

Reyispermum

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

144

Year

2018

Parent Taxon

[Class] Magnoliopsida

Fossil Status

seeds

Type

Reyispermum parvum

Diagnosis

Isolated seeds occurring singly. Seeds tiny, anatropous, bitegmic and exotestal. Seeds bilaterally symmetrical with dorsiventral plane of symmetry. Seed surface smooth without longitudinal ridges. Raphal region distinct, seen externally as a slightly raised rounded ridge that extends from the hilum to the chalazal end opposite the micropyle. Hilum and micropyle separated by a moderate zone of testal sclerenchyma. Hilar scar small, circular without a 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 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). Testa bulging below hilum. Palisade-shaped cells of exotesta with evenly thickened anticlinal walls and a straight lumen. Anticlinal walls of exotestal cells 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 in the micropylar region where the anticlinal walls are straight and the outer facets polygonal. Tegmen thin.