Variation in stomatal density in the Late Carboniferous gymnosperm frond Neuropteris ovata

Abstract

Fossil foliage cuticles of the Late Carboniferous medullosa-lean pteridosperm Neuropteris ovata show a marked drop in stomatal density and index in the very early Stephanian, and a ret urn to higher values at the end of the Stephanian. This probably reflects a rise in CO, partial pressure in the atmosphere during the Stephanian, due to a drastic contraction of the tropical forests. This interval of high atmospheric CO, levels appears to coincide with a warming interval in, both the Gondwanan and Angaran areas.