The stelar structure ofAsplenium obtusifolium and its related species (A. repandulum, A. riparium, A. triquetrum, A. volubile, A. purpurascens, A. ortegae, A. delitescens, A. hoffmannii, andA. laetum) in the New World tropics was observed and compared to that of Asian species ofAsplenium sect.Hymenasplenium. Both of the groups were found to share peculiar stelar structures: steles with two meristeles, a broader ventral and a narrower dorsal, each providing one of the two leaf traces; leaf gaps arranged in two rows between the dorsal and ventral strands, which are connected by thin meristeles, delimiting the leaf gaps. These structures are distinct from the radial symmetrical ones general inAsplenium. Together with cytological evidence, this strongly indicates that the New and Old World groups are closely related. Thus, these Neotropical species should be included in sect.Hymenasplenium.