222 



PRACTICAL BOTANY. 



2. Cut through seeds of Corn in a median plane longi- 

 tudinally at right angles to the broad sides. Notice the 

 thick double-walled coating. This consists of the pericarp 

 or wall of the ovary and the seed coat or developed integu- 

 ment of the ovule. The remains of the style will be found 

 at the apex of the smaller end of the seed. At one side, 

 near the smaller end of the seed, is the embryo. The 

 embryo is separated from the endosperm by the scutellum, 



which is an ar- 

 rangement for 

 the absorption 

 of the food for 

 the nourishment 

 of the embryo. 

 The endosperm 

 consists of two 

 parts a firm 

 yellow part on 

 the side of the 

 seed opposite the 

 embryo, and a 

 less firm white 

 part .occupying 



^ e central DOr- 



1 1 o n and the 

 larger end. Draw, showing all you have seen. Scrape 

 off some of the endosperm and mount in water. Deter- 

 mine if starch is present. If it is, draw some of the 

 grains. Dissect the embryos from seeds of corn that have 

 been softened by soaking. Make out the apical bud, or 

 plumule, pointed towards the large end of the seed, the 

 caulicle, or radicle, attached to the scutellum and pointed 

 towards the smaller end of the seed. Make longitudinal 

 sections through the radicle and examine the rootcap 

 and the rootsheath, or coleorhiza. Study the development 



FIG. 141. Transverse section through upper part of a 

 Cornstalk, as seen under low power, (x 35.) 



