290 



CATALOGUE OF TjOWEll GllEEXSAND PLANTS. 



are extremely elongated vertically (v., e.), and show very 

 striking lens-shaped cells in the vertical section (text-fig. 92, c.). 

 These cells may be even more elongated than is shown in the 

 figure ; in the actual sections some are three times as long as the 

 limiting cells illustrated. The appearance of these cells in the 

 tangential section is very striking. They frequently measure 

 250 y. and more in vertical extension. The phloem elements of 

 the soft bast are so much crushed that their details cannot be 

 described. The soft cells are in groups of numerous cells, 

 apparently tangentially extended. The hard bast forms clusters 

 of two or three up to twelve elements, most of which are 



Text-fig. $l.Aptiana radiata, Slopes. Radial longitudinal section of 

 part of a medullary ray showing: m., ordinary ray-cells, with thickened 

 pitted walls, without intercellular spaces ; ., larger square cells ; 

 >., radially elongated cells; v., vertically elongated cells all with 

 thickened pitted walls. No. V. 11517 b. 



irregularly hexagonal in shape with walls so much thickened 

 that the lumen is almost obliterated. 



AFFINITIES. The original account of the affinities of this 

 fossil (Stopes, 1912, pp. 90-91) premised that it was impossible 

 conclusively to identify it with any living genus, and conse- 

 quently a non-committal name was given to the specimen. 



