RELATION OF LEAF STRUCTURE TO PHYSICAL FACTORS 57 



Aspens C. 200 n P. 2 rows, 80 /* S. 120 n 



Spruce C. 80 /* P. i row, 25 ^ S. 55 ft 



120 ft i row, 55ft (69%) 65;* (54%) 



Light 1/27; water +(2-3%); humidity +(5-10%); tempera- 

 ture (2-3). 



ALPINE MEADOW (dwarf) : light i ; available water 12-17% J hu- 

 midity 40-55%; temperature 4O-65 : diphotophyll 175^; chlor- 

 enchym (130 /A) I close row globose to prolate and oblate palisade 

 cells, and i looser row 30/1,; loose oblong sponge cells. 



Aspens C. 200 ft P. 2 rows, Son S. 120 ft 



Meadow C. 130 ft P. 2 rows, 60 ft S. 70 ft 



-70ft 20ft (25%) 5 oft (42%) 



Light ij; water +3%; humidity (0-15%); temperature 

 10. 



Chamaenerium angustifolium 



ASPENS: light 0.8; available water 9-14%; humidity 30-65%; 

 temperature 5O-75 : diphotophyll 250^; epidermis 15/4; cuticle 

 2/*,; chlorenchym (220/4) 2 compact rows prolate palisade cells, 

 first row 75 /i ; second row 50 /i, looser ; close triangular and globose 

 sponge cells, the lower ones prolate and oblobate. (Plate VI, 

 fi g- 50.) 



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

 5i-76: differs from type only in more compact sponge. 



Light i; water (4.5-6.5%); humidity the same; tempera- 

 ture -f- i. 



GRAVELLY BROOK BANK : light i ; available water 8% ; tempera- 

 ture 55-76 : similar to type. 



Light i; water (1-6%) ; humidity the same; temperature 



-Ki-5). 



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

 30-50%; temperature 4O-65 : diphotophyll 230/4; chlorenchym 

 200 /x. ; palisade cells 50 /i ; compact globose sponge cells. 



Aspens C. 220 ft P. 2 rows, 125 A S. 95 M 



Gravel . . C. 200 /* P. 2 rows, 100 M S. IOOM 



20M 25/4(20%) +5^(5%) 



Light i; water (6.5-8.5%) ; humidity (0-15%) ; tempera- 

 ture 10. 



SUBALPINE BOG : light i ; available water 58% ; humidity 50- 



