Article: Non-vascular land plants from the Devonian of Ghana
W. G. Chaloner, M. K. Mensah and M. D. Crane
Two species of fossil plant (Spongiophyton nanum Krausel, S. lenticulare (Barbosa) Krausel) preserved as compression fossils with cuticles, are described from the ?Middle Devonian of Ghana. S, nanum, first described from the Devonian of Parana, Brazil, is a plant of dorsiventral thalloid organization, branching dichotomously, and with a series of large pores on the presumed upper surface. It has a cuticle far thicker than that of most vascular land plants. On its inner surface the outlines of cells of the underlying tissue may be seen. Nothing else is known of the inner tissue of the plant. Material of S. lenticulare is similar, but is only seen as small fragments. Spongiophyton combines an external morphology resembling that of some algae and liverworts, with a thick cuticle unknown in those groups. In this and its dorsiventral organization, it appears to show adaptation to a terrestrial environment. It may be compared with Foerstia (? = Protosalvinia) and with Parka, but shows significant differences from these and other genera of Devonian thalloid plants.