228 OLASSIFIOATIOX OF RICE 



symmetrical, both sides being parallel, or if the palea is concave, the 

 grain is almost crescentic. 



As already mentioned, the grain has ridges upon it which 

 correspond with the nerves of the glume and palea. 



Double Grains. — In a rice from Bilaspur and another from 

 Narsinghpur the glume and palea are reported to enclose two or more 

 grains. This variety has already been referred to by Prain(22) 

 under the name of Onjza sativa var Plena. Like the coloured 

 rice and the rices with clustered spikelets this also ranks as a 

 systematic variety. In the present classification the distinction 

 between single and double grained rices cannot be made a main 

 distinction. 



4jbdo7ninal White. — This term is used by Kikkawa(23) to 

 describe the presence of a chalky white portion on the ventral side 

 of certain rice grains. When it occurs in tlie centre of the grain 

 surrounded by a translucent portion, the term ' Shiratama ' is used 

 to distinguish the grain. Inagaki, quoted by Kikkawa, believes 

 that the abdominal white is nothing but a portion of the rice grain in 

 which the spaces between the starch grains have not been filled up 

 with albuminous substances. Most immature rices show an 

 abdominal white and it appears on germination in grains which 

 previously showed none. 



Micro-chemical examination of the abdominal white shows 

 that the starch grains are less closely packed in the cells in the chalky 

 white portion and that the cells contain a large amount of dextrin. 

 It would therefore seem that the abdominal white is an indication 

 that a grain is immature and that the carbohydrate has not been 

 converted into its most concentrated form. The appearance of 

 abdominal white in germinating grains is then due to the conversion 

 of starch into dextrin. It is obvious therefore that the use of the 

 presence or absence of closely related carbohydrates in a portion 

 of the endosperm as a basis for classification has nothing to recom- 

 mend it. 



Notched Grain. — Gammie(24) mentions the presence of a notch 

 on the side of the grain as a diagnostic character in the rice varieties. 



