Systematics and paleoecology of three Late Devonian floras of southern Ireland

The Devonian Period was a time of evolutionary innovation in terrestrial plants, in terms of the appearance of major organs of the plant body and in terms of the appearance and diversification of major lineages of plant groups. Three localities of Late Devonian (Uppermost Famennian) age in southern Ireland yielded plant fossils which provide new data on anatomy, morphology, range of variability, and paleoecology in arborescent lycopsids, progymnosperms, and gymnosperms.; Six taxa of anatomically preserved plants are described from Sandeel Bay, Hook Head, County Wexford. Wexfordia hookense is demonstrated to possess secondary xylem and periderm and reconstructed as an arborescent lycopsid. Three gymnosperm seeds, New Seed A, New Seed B, and c.f. Hydrasperma tenuis are described. Progymnosperms are represented by a penultimate branch of Archaeopteris c.f. hibemica and by the first report of Callixylon from Ireland. The environment of deposition at Sandeel Bay is interpreted as a cut-off channel chute of a meandering river near the coastline.; A diverse gymnosperm community is known from Ballyheige, Kerry Head, County Wexford. Quantitative paleoecological sampling identifies patterns of distribution of plant fossils across the outcrop which are utilized to provide insights to biases that result from the fossilization process. The environment of deposition at Ballyheige is interpreted as a crevasse splay on an alluvial plain.; Quarries at Kiltorcan Hill, County Kilkenny provided access to three stratigraphic levels in which different assemblages of plant fossils occur. These assemblages are compared in terms of their taxonomic composition and environments of deposition, which is interpreted as a meandering river and its associated lateral environments.; The three localities are placed into the larger context of the overall landscape of southern Ireland during the Late Devonian and compared with reconstructed communities from the Late Devonian on the east coast of North America.