384 STUDIES IN FOSSIL BOTANY 



and five or more around the pith). As the great 

 majority of the specimens show no signs of any 

 approach to the apex or base, it seems clear that they 

 represent fragments of very long stems, bearing a large 

 number of leaves. Although the stem was well con- 

 structed mechanically, thanks principally to the 

 sclerenchymatous network of the outer cortex, it 

 may be doubted whether an axis of such length and 

 such slender proportions, bearing numerous leaves of 

 large size, could have supported itself unaided in the 

 vertical position. Yet the plant shows complete radial 

 symmetry, and could not well have been of prostrate 

 habit. It is not unlikely that Lyginodendron oldhamium 

 was a climbing plant of the " scrambler " type, a 

 suggestion which is confirmed by the presence of spines 

 on the stem, and on all parts of the compound leaves. 

 These spines may well have been organs of attachment, 

 enabling the plant to cling to the trees or shrubs which 

 supported it, just as we see in the recent Fern Davallia 

 aculeata, where, however, it is only the frond, and not 

 the stem that climbs. On the other hand, a comparison 

 has been suggested with the tall, erect species of Todea, 

 such as T. australis. 



The evidence for the identification of the foliage 

 of our fossil with Sphenopteris Hbninghausi is now 

 conclusive. The agreement is exact in the venation, 

 form and size of the leaflets, and in their conchoid 

 curvature, in the mode of branching of the rachis, the 

 presence of spines on all the parts, and the reticulated 

 cortex of the petiole. Further, casts have been figured 

 by M. Zeiller, which agree closely with the stem of 

 Lyginodendron, and which at the same time bear the 



