PARTS OF SEEDS: CORN SEEDLINGS 



st 



side to the stem or caulicle and this point of connection can be seen 

 quite clearly. This is the scutellum of the embryo, so calkd be- 

 cause of its form and the central attachment at one side which 

 resembles a little shield. The stem or 

 caulicle, the leaf bud, or plumule, the* 

 root or radicle, the root sheath, and the 

 scutellum or cotyledon, make the .young 

 embryo in the corn seed. There is still 

 a large bulk of the content of the grain 



Fig. IS- 



Com grains sprouting; st. which lies against the scutellum. This 

 muie- '/radicle fn roo/sneSth is known as the endosperm. In the corn 

 oot ' it is largely made up of starch which 

 is stored food for the young embryo when the seed germinates. 



12. Germination of the corn. The root sheath usually 

 emerges first with the radicle of the embryo still enclosed. 

 While the root sheath is still 

 short, lengthwise sections will 

 show that it has ceased to elon- 

 gate, and the root has pushed 

 through it at one end. 



Fig. 16. 



Germination of corn grains, showing origin 

 of first lateral roots. Note the radicle (pri- 

 mary root) emerging from the root sheath. 

 In right-hand seedling note the remains of 

 root sheath from which the radicle emerged. 



Fig. 17. 



Germinating corn grains, 

 primary root have emerged. 



Plumule and 



At this stage sections also show, when made through the middle 

 line of the embryo, the origin of the first two lateral roots. One 

 of them lies inside in the axis of the scutellum and the leaf, 

 while the other lies opposite underneath the coat of the groove 



