46 WOODY PLANTS OF MASSACHUSETTS. 



jointed leaflets, and are netted and feather- veined, the ribs and 

 veins branching and running into each other ; while the leaves 

 of monocotyledonous plants are without joints, and have parallel 

 ribs and veins which do not thus intersect. 



The essential part of the seed of a dicotyledonous plant, the 

 embryo, is composed of two cotyledons united by a neck or 

 collar to a radicle or future root. The cotyledons are the seed- 

 leaves, which, after the germination of the seed in the earth, 

 usually expand upon the surface, as is conspicuously the case 

 with the beech and the bean. Between these seed-leaves or 

 cotyledons rises the plumule, the ascending axis, the future 

 stem of the plant. Below them shoots downward the radicle, 

 the descending axis or root. 



