STRUCTURE OF FOSSIL PLANTS 



55 



GROUND TISSUE 



Parenchyma. Simple soft cells, 

 either closely packed, as in 

 fig. 24, or with air spaces 

 between them. Compare 

 78, B, for fossil. 



Fig. 24 



Palisade. Elongated, closely 

 packed cells, /, chiefly in 

 leaves, lying below the epi- 

 dermis, <?, fig. 25. Com- 

 pare fig. 34, /, for fossil 

 palisade. 



P 



Fig. 25 



Endodermis. Cells with 

 specially thickened walls, 

 eti, lying as sheath be- 

 tween the parenchyma, 

 <:, of ground tissue, and 

 the vascular tissue, 5, fig. 

 26. Compare fig. 108 

 for fossil endodermis. 



en 



Fig. 26 



Latex cells. Large, often much 

 elongated cells, m, lying in 

 the parenchyma, /, fig. 27, 

 which are packed with con- 

 tents. Compare fig. 107, s. 



p 



Fig. 27 



