Symmetrical bifurcation of the Alethopteris urophylla frond.

Abstract

A symmetrical bifurcation of an Alethopteris urophylla frond from the Pennsylvanian (Upper Carboniferous) of the Northern France coalfield shows some still-attached remains of foliage. Such rare specimens contribute, step by step, to a better understanding of the frond architecture of the genus Alethopteris, which is of the bifurcate-pinnate type. A few complementary general comments are given.