274 



upper side lias twelve per unit. At the base of the leaf they 

 are almost completely absent. 



Fig. 21. Saxifraga tricuspidata. 



The leaf; A (2/1), Leaf-form. B, Marginal hairs. C, Spongy parenchyma. D, Transverse 



section. E, Longitudinal section. (B. D, E ■«U). {C so/i). 



The mesophyll is slightly and indistinctly differentiated, 

 and strongly recalls the condition in the section Euaizonia 

 (see below). The pahsade-cells are short and rounded, and 



