STRUCTURE OP THE SEED. 

 Fig. 112. Fig. 113. 



217 



■'..,sh 



Fig. 112. a shows the exorhizal germination of the Dicotyledonous seed of the orange ; 

 c, the Ciotyledon; £r, the first pair of aerial leaves; r, the radicle naked and without a 

 sheath. 



Pig. 113. Seed of oats sprouting." r, roots passing through the sheath, sh, from the 

 single cotyledon c. g^ The young leaves and stalk. 



to it, and which it raises with it above the earth, when its 

 elongation operates from its base. 



The cotyledons. — These are the lateral appendages of the 

 embryo axophyte. The cryptogamia have no cotyledons in their 

 embryos, which are therefore aootyledonous. The embryo in 

 such cases is called a spore, and as it gives oflF roots indiffer- 

 ently from any part of its surface, and from a fixed point, it 

 is termed heterorizal, (f^tpoj diverse.) Plants possessing coty- 

 ledons in their embryo are termed cotyledonous. If we examine 



19* 



