RELATION OF LEAF STRUCTURE TO PHYSICAL FACTORS 67 



Galium boreale 



GRAVEL: light i; available water 2.5-5.5%; humidity 30-65%; 

 temperature 55-76 : diphotophyll 250/4; epidermis, upper 40/4, 

 lower 30 p.; cuticle 5/4; chlorenchym (iSo/*) 2 close irregular rows 

 prolate palisade cells, first row 50 /*, second row 30-40/1; close 

 irregular sponge cells. (Plate VIII, fig. I a.) 



SPRUCE SHADE: light 0.03; available water 12-16%; humidity 

 40-70% ; temperature 48-72 : diphotophyll 125/1; epidermis 15 /*, 

 slightly wavy, lower surface undulating; cuticle thin; chlorenchym 

 (95 /A) i loose row funnel palisade cells 30/4; loose oblate sponge 

 cells. (Plate VIII, fig. i Z>.) 



Gravel C. :8oM P. 2 rows, 80 A* S. IOOA* 



Spruce C. 95 n P. i row, 30 A* S. 65 A* 



_ 85 A* i row, 50 A* (62%) 35 A* (35%) 



Light 1/33; water -f- 10% ; humidity +(5-10%); temperature 

 -(4-7). 



AWNING SHADE (seedling): light 0.0016; available water 12- 

 16% ; humidity 40-70% ; temperature 48-72 : diphotophyll IOO/L; 

 epidermis 15/4 slightly wavy, lower surface undulating ; cuticle thin ; 

 chlorenchym (70/4) i lacunose loose row funnel palisade cells 30 p. ; 

 very oblate lacunose sponge cells. 



Gravel C. i8oA P. 2 rows, BOA* S. IOOA* 



Awning . . . C. 70 A* P. I row, 30 f- S. 40 A* 



IIC^M i row, 50 A* (62%) 60 A* (60%) 



Light 1/600; water -|- 10% ; humidity +(5-10%); temperature 



-(4-7)- 



Holodiscus dumosa 



ROCK: light i ; available water 3% ; humidity 30-65% ; tempera- 

 ture 5i-76: diphotophyll 115^; epidermis, upper 15/4, wavy, 

 lower IO/A; cuticle 2/x; chlorenchym (90/1) 2 compact rows prolate 

 palisade cells 25 /t ; compact subglbbose sponge cells. 



SPRUCE SHADE: light 0.03; available water 12-16%; humidity 

 40-70% ; temperature 48-72 : diphotophyll 65/4; epidermis, upper 

 io/i, lower 5/*; cuticle thin; chlorenchym (50/1) i loose row funnel 

 and prolate cells, 15/x, and a second row globose cells 10/1, looser 

 or lacking; loose oblate sponge cells. 



Rock C. 90 A* P- 2 rows, 50 A* S. 40 A* 



Spruce C. 50 M P. ii rows, 25 A* S. 25 A* 



40A* i row, 25A (50%) ISA* (37%) 



