Bui. 183, U. S. Dept. of Agriculture. 

 d / 



Plate II. 



Fig. 1.— Longitudinal (Dorsi-ventral) Section of a Mature 

 Barley Grain. 



a, Starcb endosperm; &, aleurone layer; c, area of starch endo- 

 sperm, adjacent to the scutellum, representiiag the initial 

 stage of the corrosion of the endosperm. This toolc place at 

 the close of the ripening of the grain, d-r, The embryo; d, 

 plumule with investing sheath; e, primary, and e' , secondary, 

 radicles;/, scutellum, the surface next to the endosperm covered 

 with the epithelial layer (g); r, root cap of primary radicle. 



Fig. 2.— Longitudinal Section of Barley Grain, Showing 

 the Stage of Endosperm Conversion at the End of 

 the Second Day of Germination. 



Thestarch endosperm is being broken down in thedenseareas directly 

 in front of theepitheliallayer, (f), of the scutellum (s),and more 

 rapidly in the less dense areas adjacent to the aleurone layer, (o). 

 6, Clear fluid area produced during germination; c, corroded area of 

 starch endosperm; n, normal starch endosperm not yet attacked. 



