PRINCIPLES OF CLASSIFICATION 259 



exceptions, the following characters may be relied upon in 

 grouping plants with reference to these two divisions. The 

 monocotyledonous plants have endogenous stem (see page 304), 

 parallel-veined leaves and the parts of the flower arranged in cir- 

 cles of three each. The dicotyledonous plants have exogenous 

 stems (see page 304), net-veined leaves and the parts of the 

 flower in circles of four, five or some other multiple. 



