FLOURS. 



33 



t-C. 



Fig. 23. Oat Flour, (x 240.) 



a, Starch grains, some of which are irregularly rounded, more often angular 

 fusiform, or with sharp edges. 



a', Compound starch grains, mostly entire, sometimes more or less broken up. 

 ap, Aleurone layer. 



b, Brown layer ; the cells are fusiform, and very irregular in direction. 



e, Epidermis of the pericarp with thin cell walls, sometimes with, sometimes 

 without pits. 



es, Epidermis of scutellum. 



ip, Point of insertion of hairs. 



m, Debris of the hypoderma. 



p, Protective hairs, often geminate, and often much longer and narrower 

 than those shown in the illustration. 



pi, Pigment layer. 



r, Fragments of raphe, 



t, Tubular cells. 



