426 PSARONIEAE [CH. XXIII 



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 Pterido- 

 sperms. The association of fronds bearing Asterotheca and 

 Scolecopteris types of fructification with Psamnius stems recorded 

 by Grand'Eury^ 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 re- 

 production. 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. 



' Grand'Eury (77) A. p. 98. 



