204 



BOTANY OF CROP PLANTS 



~-§-'Jhiemma 



'glumej 



nated. The flowers at the tip of the inflorescence are the first 

 to open. Flower opening continues throughout the day. 

 The stamens are the first flower parts to 

 appear. After they are extended full 

 length, the lemma and palet open wider, 

 and the stigmas protrude. Usually the 

 stigmas draw back between the palet 

 and lemma after polUnation, although 

 they may remain outside. Although 

 self-fertilization is the normal process, 

 cross-fertilization is not altogether pre- 

 cluded. 



Grain. — The rice grain (caryopsis) is 

 surrounded by the lemma and palet, or 

 palet alone. These two structures form 

 the "hull." Rice enclosed in the hull is 

 known as "paddy." Rice from which 

 the hull has been removed is "cleaned 

 rice." The rice grain (Fig. 76) is 

 smooth, longer than broad, and elliptical in cross-section. 

 There are two longitudinal parallel ridges on 

 each of the flat surfaces. The grain of common 

 rice is shiny and transparent. This appearance 

 is due to the glassy endosperm. Occasionally 

 there are grains that appear dull; in such, the 

 endosperm is starchy on the outside and horny 

 within. Grains with dull areas here and there 

 are not uncommon. An interesting rice is 

 Oryza glutinosa, the grains of which always 

 appear dull. A cut surface of this rice is de- 

 scribed as paraffin-like in appearance. The 

 starch grains behave quite differently from those of common 

 rice. They color yellow-brown with iodine instead of violet- 



Fig. 



75. — Spikelet of rice 

 (Oryza sativa). 



Fig. 76.— 



Kernel of rice 



(Oryza sativa). 



e, embryo. 



X 5- 



