Structure of the Leaves of Catamites. 187 



the position assigned to it is the correct one, as several 

 longitudinal sections show that the sclerenchymatous 

 strand becomes more and more pronounced towards the 

 apex of the leaf where it runs out on the upper surface. 

 Transverse sections in this region show the assimilating and 

 the " melasmatic " tissues reduced to the form of circular 

 ares, convex towards the lower surface of the leaf, while a 

 large part of the upper surface of the section is occupied by 

 sclerenchyma. 



In view of the recent discussions on the affinities of 

 Calamostachys Binneyana* it is deserving of notice that the 

 modification last described renders the leaf of Catamites 

 very similar in structure to the sterile bracts of the 

 Calamostachys. If, in fact, we suppose a large extension of 

 the sclerenchyma on the upper side of the leaf and a great 

 reduction of the assimilating tissue of the lower, while the 

 " melasmatic " tissue retains its special characteristics, the 

 leaf of Catamites would become the bract of Calamostachys 

 Binneyana. 



General Observations and Conclusions. 



The leaves described in the preceding paragraphs are 

 those of the small ultimate branches of Catamites, and are 

 the only ones which, after much searching, I have been able 

 to find. Hence my observations throw no light upon the 

 structure of those leaves which are occasionally seen in 

 casts and impressions attached to the larger Calamitean 

 stems and which are referred to by descriptive palaeo- 

 botanists. 



It might be supposed from the small size of the leaves 



* Hick : " Cala?nostachys Binneyana " : Proc. Yorkshire Geological and 

 Polytechnic Soc, 1893: also, "The Fruit-Spike of Catamites." Natural 

 Science. Vol. 2, 1893. 



Williamson & Scott : " Further Observations on the Organisation of The 

 Fossil Plants of the Coal-Measures. Tart I. Calamites, Calamostachys, and 

 Sphe?iofihylhim." Phil. Trans., 1894. 



N 



