Cuticular analysis of new Westphalian and Stephanian Cordaites species from the USA

Four cordaitalean species from the USA are described here: Cordaites olneyensis Šimůnek, sp. nov., Cordaites daviessensis Šimůnek, sp. nov., Cordaites kinneyensis Šimůnek sp. nov. and Cordaites minshallensis Šimůnek sp. nov. They come either from below the Minshall coal or from its roof-shales in Indiana, at the Bolsovian-Asturian boundary, or from Stephanian age deposits in Illinois and New Mexico. The Westphalian cordaitaleans are from a seasonally dry habitat (between coal beds) or from a wet habitat (the roof-shales). In both cases, their cuticles have low stomatal densities on the adaxial surface; however, stomatal densities are high on the abaxial surface and stomata are arranged in stomatiferous bands. The Stephanian species come from the period where seasonal drought was more frequent, even during the wetter intervals of glacial-interglacial cycles, and cordaitalean cuticles have less variation between adaxial and abaxial surfaces. In these Late Pennsylvanian specimens, stomatal density was low on both abaxial and adaxial cuticles and stomata were arranged in stomatal rows on both sides.