198 POPULAR GEOGRAPHY OF PLANTS. 



on which, the curious Mexican hieroglyphics were painted. 

 The process of preparing the paper consists simply in leav- 

 ing the green tissue of the leaves to decay away till the 

 layers of fibres stick to each other. These plants are eight 

 years before they flower, that is to say, when they are not 

 prevented from blooming, as they are in a cultivated state, 

 by a wound made in the plant at the time the flower-shaft 

 begins to spring, " by cutting off the tuft of central leaves ;" 

 into the cavity which is thus created the sap runs, which 

 was intended to nourish the growth of the flower-shaft. 



There is another genus allied to the Maguey plant, called 

 the Mexican Yucca, of which we may form some idea by 

 imagining a lofty tree covered with a number of bell-shaped 

 flowers, generally of a greenish-white colour, or very delicate 

 yellow. 



Another thing which excites our wonder a little, is the 

 number of extraordinary -looking hedges we meet with, made 

 of a most unshapely kind of Cactus, with many branches; 

 we find them cultivated so extensively, that they form one 

 of the most prevailing features of Mexico; but this is ac- 

 counted for on discovering that it is on this kind of Cactus, 

 called Opuntla Tunas, or Opuntia coc/iinillifera, that the 

 Cochineal insect is bred. Formerly cochineal was exported 



