VI.] 



BOTANY. 



must have warmth, air, and moisture. Further on it 

 will be shown that to grow to maturity light is also 

 wanted ; but at present we are concerned only with 

 the germinating seed. 



35. From experiment now proceed to observation. 

 All seeds consist of two principal parts a dead part 

 outside and a living part within it. The living part 

 is the plantlet, or embryo, and is in fact an im- 



FIG. ii. Germination of Mustard, i Seed, 2 Embryo removed from Integu- 

 ment, 3 Radicle pushing through Integument, 4 Cotyledons and Radicle after 

 throwing off Integument, 5 Young Plant ; all twice the real size. 



mature plant, having a separate existence from that of 

 its parent : the dead parts are its coverings (integu- 

 ments), together with sometimes a nourishing matter 

 (albumen) provided for the plantlet, and like it con- 

 tained within the integuments. The pea and mustard 

 have no albumen ; the wheat has. 



