KEVIEW ON STRUCTURE OF LEAVES 





types of epidermal hairs. What use could be suggested for tin- 

 dense coat of hairs on leaves of shepherdiaf Pig. 412. 



XdTK. To study leaf tissues: A uumber of leaves can be com- 

 pared by making free-hand cross-sections of leaves held between 

 two pieces of pith or cork, ami mounting the material in water. 

 Study sin-h leaves as ivy (Hedera 

 helix), begonia, cycas, geranium, 

 and corn. Note the number of 

 layers of palisade cells, the spongy 

 parenchyma, the epidermal lay- 

 ers. Which cells bear chlorophyll ? 

 Write a brief description of the 

 tissues of each leaf and make a 

 drawing of the geranium. 



"/'- study stomates in cross- 

 section: In the cross-sections of 

 leaves of geranium, corn, ivy, lily. 

 or spider- lily prepared for the above experiment, look for theston 

 and make a careful drawing from the one you can Bee best. 



Study of stomates in surface view: From the under surface of 

 leaves of geranium and impatiens peel bits of epidermis by tearing 

 the leaf. Mounl these in water and examine under low power. Are 

 the stomates scattered or in grcupsf With aid of a higher power 

 draw a few Btomates Bhowing their guard cells and the Burrounding 

 epidermal cells. Make a similar study and Bketch of the epidermis 

 torn from the under Burface of a Begonia aanguinea leaf. 



Breathing-pores are known as itomata, singular stoma; also as 

 stomates, singular stomale. 



117. Leaf-scar of the plane 1 1 

 Bycamore. The scar surrounds 

 the trad, which was covered bj 

 the hollow base of the petiole. 



R 



Ling foi 1 1 kcl 1 1 . 



