62 



EUCALYPTUS GLOBULUS. 



aromatic, pungent taste, slightly bitter, followed by a sensation 

 of coldness. 



The microscopical structure of the leaves is quite character- 

 istic. A cross section, when magnified only a few times, shows 

 the large resin-cells loaded with bright brick-red resin and the 

 smaller oil glands in which float the oil drops of a bright yel- 

 low color. When magnified more highly the minute structure 

 of the leaf is seen plainly. In figure 2, we have a cross sec- 

 tion of the leaf cut directly through the midrib. The midrib is 

 composed mostly of wood and liber fibre which gives such great 

 strength to the frame work of the leaf. On the upper and un- 

 der surface, and in fact entirely covering it, is a very thick wall 

 of cellulose which is nearly impervious to water and to the 

 sun's rays ; at A we see this thick wall that stands duty over 



Fig. 2. Cross Section of an Eucalyptus Leaf. x$o diameters. 



the delicate central portion. The epidermis seen at B is a 

 single row of empty cells whose only object in life apparently, 

 is to give a chance for the circulation of air between the 

 outer garment of cellulose and the body of the leaf. The green 

 portion of the leaf is composed entirely of the delicate elon- 

 gated cells loaded with coloring matter called chlorophyll, while 

 to the row of cells seen at C has been given the imposing 

 name of palisade cells. Palisade cells are common to all leaves. 



