294 FINE-STRUCTURE OF PROTOPLASMIC DERIVATIVES III 



TABLE XXVI 

 CELL WALL SUBSTANCES OF THE CUTICULAR LAYERS 



Clivia 



Gasieria 



Yucca 



Dasylirion 



A 



20^ 

 12° 



4 



(\ 



12 3 4 



[\ 



'-^yr* 



12 3 4 





2(f 40° 



Fig. 145. Cuticular layers of vegetable epidermises 

 (from M.Meyer, 1938). a) Optics of longitudinal 

 section. Ordinate: Relative strength of bire- 

 fringence. Abscissa: i cellulose layer, pos. bire- 

 fringent; 2 pectin layer, isotropic; 3 cutinized 

 ''•' wall, neg. birefringent; 4 cuticle, isotropic, h) 

 Hysteresis-melting curve of the cutin wax of 

 Clivia, measured by reduction in birefringence 

 of the section. Ordinate: Retardation in degrees 

 of the Senarmont compensator. Abscissa: 

 Temperature T in °C. 



60'' 



evenly distributed over the thickness of the cuticular layer. In Clivia, 

 for instance, only an inner zone — which iodine-zinc chloride solution 

 tints dark brown — clearly contains cellulose. The waxes are in 

 greatest evidence in the middle of the layer, so that it is there that 



