274 



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

 are almost completely absent. 



Fig. 21. Saxifraga tricuspidata. 



The leaf; A {-/i), Leaf-form, ß, Marginal hairs. C, Spongy parenchyma. D. Transverse 

 section. E, Longitudinal section. (B, D, E »U), (C ä'Vi). 



The mesophyll is slightly and indistinctly differentiated, 

 and strongly recalls the condition in the section Euaizonia 

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



