In a previous paper on the anatomy and affinity of Platyzoma microphyllum R. Br. (Trans. Roy. Soc. Edin., vol. li, No. 20, 1916), the structure of a single herbarium specimen of this rare Australian fern, collected by Professor Baldwin Spencer in 1902, at Boorroololoo, N.T., was described. Attention was directed in particular to the remarkable heterophylly, the anomalous stelar structure, and the unique sporangia and spores. The facts detailed made it difficult to indicate any known fern with which Platyzoma could be reasonably compared. They might be considered to suggest a probable derivative position for Platyzoma from some Gleicheniaceous source; but their divergence from the Gleichenia characters was so pronounced that it seemed impossible to retain a view of close affinity between Gleichenia and Platyzoma.