FOLIA CAROB^. 103 



There are in addition to these hairs some beautiful glands 

 thickly scattered over the leaf surface (see c, fig. 2). These are 

 wheel-shaped, and composed of eight or ten cells. In the dried 

 leaf they are of a reddish brown color, and probably contain oil and 

 some of the essential properties of the leaf. Similar glands are 

 found on the surface of a few other kinds of leaves, and they gen- 

 erally contain "secreted resinous, gummy or other substances."* 



Fig. 4. Crystals Found in the Caroba Leaf, x 750 diameters. 



The cross sections of this leaflet gives the usual leaf structure 

 (see fig. 3). A thick cuticle protects the leaf on the upper surface 

 (a}. The epidermal cells (b) are unusually large. Directly beneath 

 these are the long slender palisade cells, filled, when fresh, with 

 bright green chlorophyll ; but in its dried condition filled only with 

 dead brown chlorophyll bodies. The lower half of the leaf is com- 

 posed of the usual loosely packed parenchyma (d) with occasionally 

 drops of oil and grayish colored, granular masses. The lower epi- 

 dermis (e) is much more delicate, while the cells are either collapsed 

 or are smaller, and the cuticle is thinner than the corresponding 

 parts on the upper surface of the leaf. Two of the large epider- 

 mal glands (h) are yet attached to the lower epidermis. 



A chemical examination of the leaf has been made, with the 



*See Bessy's Botany, p. 96. 



