CHAPTER XXIII. 



Psaronieae. 



This family name, first suggested by Unger, may be con- 

 veniently adopted for the numerous species of petrified tree- 

 fern stems characteristic of the Lower Permian and Upper 

 Carboniferous strata. In his monograph Uber die Staarsteine 

 published in 1854, Stenzel* referred to the Psaronieae as a 

 special sub-division of the Filices most nearly allied to the 

 Polypodiaceae. There is now a consensus of opinion in favour 

 of including Psaronius in the Marattiales, or at least of regarding 

 the genus as more closely allied to the Marattiaceae than to any 

 other family. While admitting that the balance of evidence is 

 in favour of this view, it is probably wiser to retain the dis- 

 tinctive term Psaronieae on the ground that species of Psaronius 

 differ in several respects from any recent ferns, and because 

 of our comparative ignorance in regard to the nature of the 

 fructification. 



Psaronius. 



This generic name was proposed by Cotta in his classic 

 work Die Dendrolithen^. The stems so named, formerly included 

 by SprengeP in the genus Endogenites, had long been familiar 

 as petrified fossils. Most of the specimens described by the 

 earlier writers were obtained from Lower Permian rocks in the 

 neighbourhood of Chemnitz, Saxony. The mottled appear- 



1 Stenzel (54) p. 803. " Cotta (32). 3 Sprengel (28). 



