The peculiar structure of the adult stem in the Marattiaceae has since long drawn the attention of many investigators, and a good deal of work has been devoted to the elucidation of the morphology of the stelar structures in the stem of these ferns. The papers of Mettenius (12), Kuhn (9, 10), Shove (18), Brebner (3), Farmer and Hill (4), Gwynne Vaughan (19, 20), Charles (7), West (21) and Blomquist (2), have made us acquainted in good detail with the arrangement of the vascular parts in the stem of the most important forms of the Marattiaceae.