WINSLOWIA TUSCUMBIANA GEN. ET SP. NOV. (CHALONERIACEAE): A CORMOSE, HETEROSPOROUS, LIGULATE LYCOPSID RECONSTRUCTED FROM THE INSIDE OUT FROM THE PRIDE MOUNTAIN FORMATION (LATE MISSISSIPPIAN/SERPUKHOVIAN) OF NORTHERN ALABAMA

摘要

Plant fossils recently recovered from the Pride Mountain Formation (Mississippian/Serpukhovian) of northern Alabama include a single type of rooting base preserved as casts and permineralizations, a single stem type preserved as compressions and permineralizations, and compressions of a single type of leaf, sporophyll, and megaspore, suggesting that this was a monospecific assemblage and facilitating whole-plant reconstruction. Permineralized specimens were analyzed by means of cellulose acetate peels, and compressions were analyzed as hand samples with selected macerations. These heterosporous, ligulate, cormose, isoetalean lycopsids are semiherbaceous with frequent variable branching. The lobed base produces forking rootlets and a small amount of secondary xylem. Internal anatomy transitions into external morphology, conforming to known isoetalean lycopsid characters from both compression and permineralized specimens with sufficient variation to suggest that this plant constitutes a new genus and species that should be known as Winslowia tuscumbiana Dunn, Atkinson, Lacefield, and Rischbieter. Reconstructing whole plants is one of the primary goals of paleobotany, and this rare occurrence of permineralized and compression remains representing all the organs of a plant in a monospecific assemblage allows for the reconstruction of this plant from the inside out as a much-branched, cormose Mississippian lycopsid.