122 NATURE ( >F A PLANT'S LIFE 



that the endosperm forms the larger part of tin- grain and that 

 the embryo is relatively small, consisting <>\ a root, plumule, of 

 several closely wound leaves, and a shield like organ, tin- scu- 

 tellum (Fig. 86, /■'. C). The entire embryo may easily he re- 

 moved from the endosperm with a knife if the seed is thoroughly 

 soaked. Unlike the two preceding examples the corn is a mono- 

 cotyledon and many regard the scutellum a- a modified coty- 

 ledon. This organ forms the enzymes which put int<> soluble 



form the f 1 in the endosperm and it also functions a- an 



absorbing organ of the embryo (Fig. 86, D). Similar devices 

 for absorbing the storage foods and transferring them to the 

 embryo are seen in the wheat, onion, date, and cocoanut. The 

 early growth of the embryo goes on as in the preceding examples. 

 The root first emerges and anchors the grain in the soil. The 

 plumule of closely rolled leaves forms a sharp bodkin that reaches 

 up through the soil with ease. This modification of the plumule 

 would appear to be of a decided advantage and you will notice 

 that this method of emerging from the soil is followed by a great 

 mam plants with underground stems; see tlu- large leaves of the 

 skunk cabbage, may apple. Solomon's seal. etc. The rest ,,t 



the grain remains in the ground as in the case <>f the pea. 



57. The Two Phases in the Life of a Plant.— As has been 

 stated the plumule unfolds in all th< S like a bud and 



gradually develops int.. the mature plant. This may be effected 

 in <me year "V several years may he required to complete the 

 work. \t some time in this growth flowers will appear bearing 



5porophylls and spores and thus we arrive again at the starting 

 point in the life histO!*) of a plant. There air two distinct phases 

 or generations in the lif«- of a plant. The formation of the 

 megaspores ami microspores marks tlu- beginning of tlu- sexual 

 generation or gametophyte which ends when the male and female 

 gametes have been developed. Tin- formation of the gameto- 

 spore marks the beginning of the asexual generation or sporo- 

 phyte which ends in the sporophylls when those cells, called the 



-pore mother cells, appear which produce the micro- and mega 



spores. Th, generations are also sharply distinguished 



from each other b) tin number of chromosomes, page \<>. which 



