RELATION OF LEAF STRUCTURE TO PHYSICAL FACTORS 73 



THICKET: light 0.0125 ; available water 11% ; humidity 38-80% ; 

 temperature 53-85 : diphotophyll 75/1,; epidermis, upper 15/4, 

 lower 10 /A ; cuticle thin ; chlorenchym (45 /u,) i lacunose row funnel 

 palisade cells 2511; lacunose oblate sponge cells. (Plate VIII, 

 fig. 6fc.) 



Mesa C. 150 /< P. i row, 75 p S. 75 M 



Thicket C. 45 M P. I row, 25 M S. 20 A* 



105/1 SOM (66%) 55 /* (73%) 



Light 1/80; water +(7-9%) ; humidity +(3-10%) ; temperature 

 -4- 



Monarda menthifolia 



HALF GRAVEL: light i; available water 4.5-7.5%; humidity 30- 

 65%; temperature 5i-76: diplophyll 250/0,; epidermis 25^; 

 cuticle 4/*; chlorenchym (200 /*) i row prolate palisade cells ioo/u 

 next to upper epidermis, and i looser row prolate and oblobate cells 

 50 /* next to lower epidermis; loose central sponge cells. (Plate 

 VIII, fig. 7 a.) 



THICKET: light 0.016; available water 15-20%; humidity 40- 

 70%; temperature 48-72 : diphotophyll looju,; epidermis, upper 

 20 /*, lower 15 /A ; lower surface very wavy ; cuticle thin ; chlorenchym 

 (65/11) i loose row funnel palisade cells 40 /A ; lacunose oblate sponge 

 cells. (Plate VIII, fig. 7 &.) 



Half gravel C. 200 /* P. 2 rows, 150 A S. 50 /* 



Thicket . . . C. 65 M P. I row, 40 M S. 25 n 



135*1 i row, IIOM (73%) 25 M (50%) 



Light 1/65; available water +(10.5-12.5%); humidity +(5- 

 10%) ; temperature (3-4)- 



Ximenesia encelioides 



FOOTHILL MESA: light i; available water 2-4%; humidity 28- 

 77%; temperature 57-89 : diplophyll 325^; epidermis, upper 

 25/i, lower 15/4; cuticle thin; chlorenchym (285/11.) 4-5 compact 

 rows prolate cells, uppermost 125 /*, second row 75 ft, lowermost 

 40 p ; lower and central cells sponge-like. 



FOOTHILL THICKET: light 0.0125 ; available water 11% ; humidity 

 38-80%; temperature 53-85 : diphotophyll 200 /A ; chlorenchym 

 (i6o/*) i compact row prolate palisade cells 6o/*; close subglobose 

 sponge cells. 



