BOTANICAL CHARACTERS 



119 



average of 

 average of 

 average of 



(r) Circumference of ear at 2 inches from tip: maximum inches; 



minimum inches ; average of ten inches. 



(5) Weight of ear: maximum oz. ; minimum 0/ 



ten oz. 



(r) Weight of cob: maximum oz. ; minimum oz 



ten oz. 



(//) Percentage of grain: maximum ; minimum 



ten 



(v) Circumference of cob at 2 inches from butt : inches. 



(tr) Ratio of circumference of cob to that of ear ; 



90. The Grain. — The grain of maize and other grasses is 

 often spoken of as a seed, but it is in reality more than a seed, 

 it is a whole fruit. It is a peculiar form of fruit, for the peri- 

 carp or outer covering of the fruit is completely united with 

 the seed-coat. This special 

 form of fruit is called a 

 caryopsis. 



The caryopsis of the 

 maize plant comprises the 

 following parts : — the hull, 

 which is the combined peri- 

 carp and seed-coat ; lying 

 immediately under the hull 

 is a layer of cells known 

 as the aleurone layer (Figs. 

 15A and 6oj. The hull 

 and aleurone layer together 

 enclose the main mass of 

 the grain. This consists 

 of two distinct parts, the 

 endosperm and the embryo 

 (Fig. 1 5 J). The grains are 

 arranged with the embryo 

 side towards the tip of the FlG ^ 6o ._ EnIarge d Rec tion through hull 



ear ; when the ear hangs of maize grain. />, pericarp ; f, testa or 



Clown, the embryo is then seed coat ' "• P«=™r«m; a, aleurone 

 * laver ; j, endosperm, (i'rom Passmore and 



on the under side of the vVebber.) 



CHAP. 

 IV. 



The grain may be firm on the cob or movable. Movable 

 grains may, sometimes, be due to the ear being not fully 

 mature when gathered, or to lack of adequate moisture at the 

 time of ripening off. The grain may be set on at right angles 

 to the surface of the cob, or it may slant towards the tip. 



