186 THE ELEMENTS OF VEGETABLE HISTOLOGY 



63, No. 2) occurs immediately beneath the epidermis. 

 These subepidermal cells are frequently present in 



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Plate 63. — Leaf Structure. 



Transverse Section, Ficus Leaf. 1. Upper epidermis. 2. Subepidermal or 

 hypodermal layer. 3. Cystolith in subepidermal cell. 4. Palisade cells. 5. Meso- 

 phyll or leaf parenchyma; 6. Lower epidermis, showing stoma. 



the leaves of tropical plants and may be of use in pre- 

 venting excessive evaporation of water from the inner 

 leaf tissues. Stomata or breathing pores are present 



