RELATION OF LEAF STRUCTURE TO PHYSICAL FACTORS 55 



Spruce ...... C. i6oA* P. 2 rows, IOOA* S. 60 A* 



Half gravel . C. 175 A* P. 2 rows, 125 M _ S. 50 M _ 



+ 15 A* +25M (25%) IDA* (16%) 



Light 33/1 ; water 8%; humidity (5-10%); temperature 



Heracleum lanatum 



SHADY BROOK BANK: light 0.016; available water 25-30%; hu- 

 midity 60-85%; temperature 47-69 : diphotophyll IOO/A; epi- 

 dermis, upper 20 ft, lower lOft; cuticle thin; chlorenchym (70 ft) I 

 loose row of funnel palisade cells 35 ft ; loose oblate sponge cells. 



OPEN SPRUCE: light i; available water 12-16%; humidity 40- 

 70%; temperature 4.8 -7 2 : diphotophyll 150 ft; epidermis, upper 

 25 ft, lower 15 ft; chlorenchym (no ft) i loose row of prolate pal- 

 isade cells 60 ft ; loose oblate sponge cells. 



Shade ......... C. 70 A* P. i row, 35 A* S. 35 At 



Sun ........... C. i IDA* P. i row, 60 A* S. 50 /* 



+ 40 /* +2S A* (71%) +15^ (43%) 



Light 65/1; water (13-14%); humidity (15-20%); tem- 

 perature + (i-3). 



Rudbeckia laciniata 



SHADY BROOK BANK: light 0.012; available water 15-20%; hu- 

 midity 60-85%; temperature 47-69 : diphotophyll lobft; lower 

 epidermis 15 ft; cuticle 2 p.; chlorenchym (i2Ofi) i lacunose row 

 prolate palisade cells, 60 ft; lacunose oblate sponge cells. (Plate VI, 

 fig. 6 a. ) 



ASPEN CLEARING: light i; humidity 30-65%; temperature 51- 

 76 : diphotophyll 275 ft ; epidermis 25 /A ; cuticle 4 /t ; chlorenchym 

 (225^1) i compact row prolate palisade cells, 75ft, and a lacunose 

 row, 50 ft; lacunose triangular sponge cells. (Plate VI, fig. 6 &.) 



Brook bank C. 120 A* P. i row, 60 A* S. 6oM 



Aspens C. 225 A* P. 2 rows, 125 A* S. IOOA* 



+ 105 A* +i row, +65 A* (108%) +40 A* (66%) 



Light 80/1; water the same; humidity (20-30%); tempera- 

 ture (3-4). 



Primula parry i 



ALPINE ROCK CLEFT: light 0.05; available water 12-17%; hu- 

 midity 40-60%; temperature 3O-55 : diphotophyll 350 ft; epi- 

 dermis, upper 25ft with raised stomata, lower 20 /i; cuticle thin; 



