LEPIDOSTROBUS 179 



corresponds to the parichnos-strand in the vegetative 

 axis (see pp. 148 and 155). 



The sporophylls in L. oldhamius are more than a 

 centimetre in length, and stand out at almost a right 

 angle with the axis. Each consists of a long, slender 

 pedicel, terminating in a foliaceous lamina. Near the 

 axis the pedicel is narrow, with a triangular section, 

 while further to the exterior it becomes broader and 

 flatter. It consists chiefly of thick-walled tissue like 

 that of the outer cortex, and is traversed by the vascular 

 bundle, which retains essentially the same structure as 

 in the cortex. The lamina broadens out rapidly at 

 the end of the pedicel, where at the same time it attains 

 a considerable thickness. It turns upwards almost at 

 a right angle with the pedicel, and becomes both 

 narrower and thinner towards its termination. The 

 general form of the lamina is thus lanceolate ; as 

 mentioned above, it has a shorter downward prolonga- 

 tion, rendering the whole somewhat peltate (see 

 diagram, Fig. 71). The structure is simple, the 

 mesophyll consisting of rather small-celled parenchyma, 

 in the outer layers of which the cell-walls are much 

 thickened. The single vascular bundle which traverses 

 the lamina is surrounded by a very well developed 

 transfusion-tissue of short spiral or reticulated tracheides, 

 most abundant where the leaf is thickest. In this 

 respect the sporophyll resembles the foliage-leaf, and in 

 both cases this accessory system of tracheides no 

 doubt served to facilitate the supply of water to the 

 mesophyll. 



An interesting feature of the sporophyll is the 

 ligule, the presence of which was demonstrated by 



