Keratosperma allenbyensis seeds from the Middle Eocene Allenby Formation near Princeton, British Columbia were reexamined from over 200 new specimens. Anatomical characters have shown their affinities to seeds of Araceae, Subfamily Lasioideae. The seeds were reexamined using the cellulose acetate peel technique modified for hydrofluoric acid.
Seeds are campylotropous with three rows of spiny ridges on the integument.
Idioblasts that contained raphides are found scattered in the outer integument. The micropylar end of the seed shows an epistase and a thin micropylar cover that was easily displaced at the time of germination. At the chalazal end of the seed a prominent hypostase and podium are present. Endosperm tissue and monocotoledonary embryos are present in some but in most specimens these tissues have been invaded by fungi. Anatomical comparisons with the extant lasioids Cyrtosperma ferox Linden et N. E. Br.