RELATION OF LEAF STRUCTURE TO PHYSICAL FACTORS 51 



chlorenchym (65^) i loose row broad funnel palisade cells 25/4; 

 oblate lacunose sponge cells. 



Spruce C. 60 M P. 2 rows, 40 /* S. 20 /* 



Awning .... C. 65 M P. i row, 25 f> S. 40 M 



+ 5M i row, is/* (38%) +2o/* (100%) 



Light 1/20; moisture probably greater on account of the deep 

 shade, but unmeasured. 



Galium trvfiorum 



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

 40-70%; temperature 48-72 : diphotophyll 165^; epidermis, 

 upper 30 ju,, lower 15-25/11, with enlarged cells; cuticle thin, chlor- 

 enchym (115 /A) i row funnel palisade cells 50^; irregular to oblate 

 sponge cells. (Plate VI, fig. 2 a.) 



SHADY BROOK BANK: light o.on; available water 18-20%; hu- 

 midity 60-85%; temperature 47-69 : diphotophyll 125 /A; epi- 

 dermis, upper 25 fi, lower 20 p.; chlorenchym (So/*) i row broad- 

 based funnel palisade cells 25 ^ ; lacunose oblate sponge cells. 

 (Plate VI, fig. 2 &.) 



Spruce C. USA* P. i row, 50 M S. 65 M 



Brook bank ... C. 80 f- P. i row, 25 M S. 55 M 



25/4 (50%) IOM (15%) 



Light 1/3; water -f (4-6%) ; humidity -f- (15-20%) ; tempera- 

 ture (i-3). 



Geranium richardsonii 



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

 40-70%; temperature 48-72 : diphotophyll i6o/*; epidermis, 

 upper 20 /i, lower 15/4; cuticle thin; chlorenchym (125/1,) i loose 

 row prolate palisade cells 60 /*; loose oblate sponge cells. (Plate 

 VI, fig. 3 a-) 



SUNNY BROOK BANK: light i; available water 40%; humidity 

 50-70%; temperature 5O-75 : diphotophyll 300^; epidermis, 

 upper 35^., lower 2O/*; cuticle 3/4; chlorenchym (250^) 2 loose 

 rows of prolate palisade cells, first row 75 ),, second row oblobate 

 cells 65 /*; loose irregular and oblate sponge cells. (Plate VI, 

 fig- 3&.) 



