The roots of _Psaronius_, more especially as regards the stelar structure, are in close agreement with those of Marattiaceae. The reference to Marattiaceae of the great majority of fertile fern-like fronds from Permian and Carboniferous rocks constituted a strong _a priori_ argument in favour of including _Psaronius_ stems in the same family, especially when it was known that leaves with Marattiaceous synangia were borne by species of this genus. It is, however, well to remember the change in our views as to the dominance of Marattiaceae in Palaeozoic floras consequent on the discovery of the Pteridosperms. The association of fronds bearing _Asterotheca_ and _Scolecopteris_ types of fructification with _Psaronius_ stems recorded by Grand’Eury[1094] is a point in favour of the Marattiaceous affinity of this extinct genus, but it is not impossible that _Psaronius_ stems bore fronds which produced Pteridosperm organs of reproduction. In this connexion the specimen represented in fig. 297 is of interest, as the fronds (_Pecopteris Sterzeli_) borne on the _Psaronius_ stems are hardly distinguishable from the seed-bearing leaves known as _Pecopteris Pluckeneti_. The position of _Psaronius_ may be best expressed by assigning it to a separate family, the Psaronieae, as advocated by Stenzel, and by regarding it as one of the many instances of a generalised type which in the sum of its characters approaches most nearly to the Marattiaceae. CHAPTER XXIV. Ophioglossales (Fossil). The fossils hitherto classed with the Ophioglossales are not such as afford any satisfactory evidence in regard to the past history or phylogeny of the group. In the generalised class of Palaeozoic ferns, the Botryopterideae, we find certain characters suggesting comparison with recent members of the Ophioglossaceae, but no trustworthy records of these eusporangiate ferns are furnished by the older plant-bearing strata. [Illustration: FIG. 301. _Rhacopteris_ sp., Ballycastle, Ireland. From a specimen in the Manchester Museum. [M.S.]]