EXOGENS. 151 



The RHIZOPHORACE^E, or Mangrove family, is named 

 after Rhizophora Mangle, the Mangrove, which forms 

 thickets at the muddy mouths of rivers in tropical 

 countries, and sends out adventitious roots which often 

 raise up the main trunk, and give the tree the appear- 

 ance of being supported on stalks. (Fig. 62.) The fruit 

 is sweet and edible. 



The Myrtle family (MYRTACE^E) contains trees or 

 shrubs which are usually natives of warm countries. 

 Some of the genera are peculiar to Australia, as the 

 Eucalyptus, or Blue Gum-tree, which is being planted 

 extensively in California. It is a rapid grower, and 

 promises to be serviceable as a forest tree. It contains 

 a medicinal balsamic resin. The Pimento, (Myrtus Pi- 

 menta,) the Pomegranate, (Punica Granatum,) and vari- 

 ous species of edible Guavas and Rose-apples belong to 

 this order. . 



The Evening Primrose (CEnothera) and the FucJisia 

 belong to the order ONAGRACE^E, or the Evening Prim- 

 rose family. 



The Cucumber family (CUGURBlTACEyE) contains many 

 plants that are drastic purgatives, and others whose fruits 

 under cultivation are edible, as the Melon and the Colo- 

 cynth, both species of the same genus, (Cucumis.) 



The Passion-flowers (PASSIFLO RACEME) received their 

 name from a fancied resemblance to the scenes at Cal- 

 vary. The superstitious monks saw in the five anthers 

 a resemblance to the wounds of Christ ; in the triple 

 style, the three nails on the cross ; in the central pillar, 

 the cross itself; and in the filamentous processes, the 

 rays of light round the Saviour, or the crown of thorns. 



