PTEROPSIDA 127 



Eusporangiatae 



Marattiales 



Asterothecaceae* Psaronius* Asterotheca,^ 



Scolecopteris,* Acitheca,"^ 



Eoangiopteris* 

 Angiopteridaceae Angiopteris 

 Marattiaceae Marattia 

 Danaeaceae Danaea 

 Christenseniaceae Christensenia 



Ophioglossales 

 Ophioglossaceae Ophiglossum Botrychium, 



Helmin thostachys 



Marattiales 



It was customary in the past to describe the Carboniferous 

 as the Age of Ferns. This was because of the abundance of 

 large fern-like fronds in the coal-measures, but it is now 

 known that many of them really belonged to gymnosperms, 

 for they have been found in association with seeds. Indeed, 

 it is now suspected that most of them were gymnospermous. 

 However, there can be no certainty about sterile fronds and 

 these must, therefore, be placed in a number of form genera 

 defined on the basis of the overall shape of the frond and on 

 the shape and venation of the pinnules. Pecopteris is one of 

 these and a large number of species are known. Some of 

 them were certainly gymnosperms, but others were equally 

 certainly ferns, for they bore sori of thick-walled sporangia. 

 The frond, sometimes as much as 3 m long, was many times 

 pinnate and the pinnules were attached along their entire 

 base, each with a single midrib. The lateral veins were some- 

 what sparse and branched dichotomously once or twice 

 (Figs. 19D and 19E) or remained unbranched. 



Asterotheca is the name given to pecopterid fronds bearing 

 sessile sori made up of four or five sporangia fused at the 

 base into a synangium, but with the distal part free (Fig. 



