IX] 



THE PHYLLOPODIUM 



167 



the normal curve (Fig. 1 57, b), sometimes forming strands with xylem-masses 

 of various outline (Fig. 1 57, e), but clearly related to the usual curve, of which 

 they may be regarded as modifications. The basal splitting of the curve is 





[\f]f 



Fig. 160. Reconstruction of the vascular system of the axis of 

 Gymuogra7nme japonica, showing how a stele with alternate 

 leaves, each with bi-partite leaf-trace, may be further disinte- 

 grated by irregular perforations. (After McLean Thompson.) 



probably in relation to ventilation, and its effectiveness is readily seen from 

 the reconstruction q{ Gymnogramme japonica, where a long slit opens directly 

 into the central pith. Two somewhat similar slits appear about half way 



