Frond architecture of the seed-fern Macroneuropteris scheuchzeri, based on Pennsylvanian specimens from the Northern France coal field

An exceptional collection of remarkably informative specimens of Macroneuropteris scheuchzeri from the Bolsovian (ex Westphalian C) of the Northern France coal field shows a bifurcate semi-pinnate type of frond architecture. This collection allows the circumscription of the variability of the main characters of the frond. Reconstructions of the frond and of the whole plant are proposed. Morphological, taxonomical, and palaeogeographical implications are analyzed.