ILLUSTRATION No. 12. 



Fig. I. 



Fig. II. 



Fig- I- Fig. II. 



:ut from date tree and exposed to a hot sun for two hours approximately. Leaf just cut from the same date tree, 



that the leaflets have closed along their longitudinal fold, owing to Note that both upper and lower surfaces of t 



ss of water. The stomata on the normal upper surface of the leaflet leaflets are freely exposed to the air. 

 )ing now enclosed in the fold and sheltered from the dry air, trans- 

 iration is reduced, 



ilvinus. P. Pulvinus. 



h "'fatie li 



