XXVIl] GLOSSOPTERIS 505 



irregularly winged axis like the stem of Onoclea. Zeiller^ has 

 replied in detail to Oldham's interpretation and adheres to his 

 original view, that the rhizome consisted of a solid axis with 

 radial wings or flanges which at intervals anastomosed trans- 

 versely in pairs at the nodes. It may, however, be possible that 

 the spaces between the longitudinal and transverse grooves on 

 a Vertebraria axis, which have been filled with the surrounding 

 rock, were originally occupied in part at least by secondary wood, 

 and the transverse strips of carbonaceous material^ lying in the 

 grooves may represent medullary-ray tissue and accompanying 

 leaf-traces. The longitudinal striations seen in some specimens 

 of Vertebraria on the areas between the grooves may be the 

 impressions of woody tissue. It is impossible without the aid 

 of more perfectly preserved material to arrive at a satisfactory 

 conception of the structural features of a complete Glossopteris 

 rhizome. 



In the specimen of Glossopteris Browniana shown in 

 fig. 339 several leaves are attached to an axis which shows 

 none of the surface-features of Vertebraria. I am indebted 

 to the kindness of Dr Mohlengraaff of Delft for the loan of this 

 specimen which was obtained from Permo-Carboniferous rocks 

 in the Transvaal. An axis figured by Etheridge^ from an 

 Australian locality bears a tuft of Glossopteris leaves, possibly 

 G. Browniana ; in place of the rectangular areas characteristic 

 of Vertebraria it shows transversely elongated leaf-scars or, on 

 the internal cast, imbricate rod-like projections which Etheridge 

 suggests represent vascular bundles. 



Glossopteris indica, Schimper. Figs. 340, A, 341. 



It is a question of secondary importance whether or not 

 the fronds which Brongniart spoke of as a variety of Glossopteris 

 Browniana should be recognised as specifically distinct. The 

 careful examination by Zeiller of the venation characters has, 

 however, afforded justification for separating G. Broivniana and 

 G. indica. We must admit that the slight and not very constant 



» Zeiller (02). = Zeiller (02) PI. v. fig. 7. '' Etheridge (94). 



