PATTERNS OF ECOLOGICAL SUCCESSION WITHIN THE UPPER PENNSYLVANIAN DUQUESNE COAL OF OHIO (USA)

Root penetration analysis was used as a quantitative test of probable order of species turnover within the ancient peat-accumulating swamp p reserved by the Late Pennsylvanian (Stephanian B equivalent) age Duque sne Coal of Ohio (USA). Quantitative results support the following mod el: Initial stages of peat accumulation in the ancient swamp were domi nated by aerial debris from vegetation growing near the swamp margin. Through this debris grew an assemblage of plants dominated by the lyco phyte Chalaneria cormosa. There was a gradual transition to an assembl age dominated by a pteridosperm and tree fern canopy with numerous gym nospermous and pteridophytic subcanopy species, and extensive herbaceo us ground cover of the zygopterid fern Corynepteris. Late stages of ec ological succession were dominated by Psaronius tree ferns.