RELATION OF LEAF STRUCTURE TO PHYSICAL FACTORS 37 



4/4; chlorenchym (350 /A) 3-4 loose rows subglobose to prolate 

 palisade cells 50/4; loose subglobose sponge cells. (Plate III, 

 fig. 8.) 



Besseya plantaginea: 2-3 rows palisade cells 50-60/4. 



Besseya alpina: leaf 300 /A; palisade cells 35-50/11. 



Draba aureiformis (available water 9-14%) : closer sponge. 



Pirola chlorantha (light 0.03). 



Draba sp. : leaf 325 /A 



Androsace subumbellata: palisade cells 60-75/4; sponge cells 

 irregular and more loosely arranged. 



SALIX SAXIMONTANA : diphotophyll 225 p. ; epidermis 25 /A ; cu- 

 ticle, upper 5/4, lower 2 p.; chlorenchym (175 /A) 3 compact rows 

 prolate palisade cells 40/1; loose sponge cells. (Plate IV, fig. I.) 



Salix pseudolapponum: upper epidermis 20 /A; cuticle 2 /A; third 

 row of palisade looser 30/1,; close somewhat prolate sponge cells. 



Salix nuttallii: compact somewhat prolate sponge cells. 



POPULUS TREMULOIDES: diphotophyll 200 /4j epidermis 15 p.; 

 cuticle 2 /A with papillae, smaller and more scattered on lower sur- 

 face; chlorenchym (170 /A) 2 close regular rows prolate palisade 

 cells 45 /A; loose triangular and oblate sponge cells. (Plate IV, 



fig. 2.) 



Rhus trilobata: no papillae ; sponge somewhat prolate. 



Geum oregonense: leaf 250/4; epidermis, upper 35 /A, lower 20 /A; 

 chlorenchym (195/4) 1-2 rows palisade cells 50-100/4; sponge cells 

 close and subglobose ; no papillae. 



Polygonum viviparum: leaf 350/4; cuticle 2/4. 



Betula glandulosa (sub-type): diphotophyll 200/4; epidermis 

 25/4; cuticle 2/4; chlorenchym (150/4) 2 rows prolate palisade cells 

 30/4, the first compact, the second looser; lacunose oblong sponge 

 cells. 



Betula occidentalis. 



Aquilegia coerulea: upper epidermis 30/4; papillae on both sur- 

 faces. 



Fragaria pumila: leaf 175 /A; epidermis, upper 35/4, lower 25/4; 

 tissues closer. 



Aquilegia brevistylis (sub-type) : leaf 200/4; epidermis, upper 

 30 /A with papillae, lower 25-50 /A, wavy ; cuticle 2 /4 ; chlorenchym 

 (140/4) 2-3 compact rows prolate palisade cells 30/4; close globose 

 sponge cells. 

 4 



