STRUCTURE ET DIFFERENCIATION DU SYSTEME CONDUCTEUR DE L'HEPATIQUE ANTIPODIALE HYMENOPHYTON FLABELLATUM (LABILL.) DUM. EX TREV. (METZGERIALES)

Abstract

  The liverwort Hymenophyton flabellatum possesses a dendroid gametophyte with a repetitive pattern in its organization. Its morphogenesis is described. A correlated light and electron microscope (SEM and TEM) study is made of its water-conducting system. The conducting elements bear a superficial ressemblance to the tracheids of vascular plants. However, both the ultrastructure of their walls, which are perforated by small plasmodesmata-derived pores, and the absence of lignin, readily separate these cells from the tracheary elements of true vascular plants.