300 



STARCHES OF GRAMINACE^. 



The reaction begins in some of the grains in 1^ minutes with ferric chloride. It is over in most 

 of tlie grains in 10 minutes and in all in 15 minutes. The reaction is the same qualitatively as that 

 of the grains of White Kaffir corn. 



The reaction with Piirdy's solution begins in some of the grains in a minute, but it does not 

 advance appreciably further even during an hour. 



STARCH OF ANDROPOGON SORGHUM VAR. (SHALLU). (Plate 1, figs. 3 and 4. Chart 12.) 



Histological Characteristics. In form both simple and compound grains are found, chiefly the 

 former. There are a few aggi-egates. The conspicuous forms are the polygonal, round or rounded 

 oval. Grains arc occasionally observed that are broadly triangular, with a curved base and rounded 

 angles; also, some that are lenticular and diamond-shaped. Among the aggregates, the type most 

 frequently found is one large grain, usually broadly triangular in sliape, with a small one closely 

 attached to it. Some of the isolated grains are dome-shaped, with either pointed or flattened base, 

 or finger-shaped, or polygonal. The grains are rather more angular and more varied in form than 

 those observed in White Kaffir corn. 



The hilum is a clear, refractive spot which is centric in the round forms and slightly eccentric 

 in the oval and polygonal grains. More than one hilum is occasionally observed in a grain. There 

 may be either a cavity, or one or more clefts, at the hilum. One short, transverse cleft may be 

 present; but more often two are arranged in the form of a cross, or three in a Y-shaped figure. The 

 clefts have the same character and shape as noted for White Kaffir corn. 



The lamellm are generally invisible. Their character and number could not be determined, as 

 is the case of the other sorghums. 



The grains vary in size from the smaller, which are 2 by 2|U, to the larger, which are 24 by 24/i. 

 The common size is 15 by 15ju. 



Polariscopic Properties. The figure is centric, reg^ilar, and very distinct. The lines are rather 

 thick and generally straight and broadening towards the margin. The figure is more often irregular 

 in size and shape than in White Kaffir corn. 



The degree of polarization is high. There is a slight 

 variation among the grains, and also occasionally in the 

 same aspect of a grain. It is about the same as in White 

 Kaffir corn. 



With selenite the quadrants are well defined, and 

 vary less in size and shape than in White Kaffir corn. 

 The colors are pure. 



Iodine Reactions.- With a 0.25 per cent Lugol's solu- 

 tion the grains all color a fairly deep violet; and mth a 

 0.125 per cent solution they color lightly, but the shade 

 does not deepen rapidly. The color is the same as that 

 of the grains of White Kaffir corn. After heating in 

 water until all the grains are completely gelatinized, the 

 solution colors lightly and the gelatinized grains very 

 deeply on the addition of iodine. After boiling for 2 

 minutes the solution colors very deeply, but the gelatin- 

 ized grain-residues not at all. The capsules all color 

 red or red-violet with an excess of iodine. 



Staini7ig Reactions. With gentian violet the grains 

 begin to stain at once, and in 30 minutes they are lightly stained, some more than others 

 is less than that of the grains of White Kaffir corn. 



With safranin the gi-ains begin to stain at once and in 30 minutes they are lightly stained, 

 some more than others. The stain is slightly less than that of the grains of AVhite Kaflu- corn. 

 Temperature Reaction. The temperature of gelatinization is 66 to 67.8 C, mean 66.9. 



Effects of Various Reagents. With chloral hydrate-iodine the reaction begins in 30 seconds. 

 It is over in two-thirds of the grains in 6 minutes, in nearly ail in 15 minutes, and in all in 20 min- 

 utes. It is the same qualitatively as that of the grains of White Kaffir corn. 



The reaction with chromic acid begins in all the grains in 30 seconds and is over in 3 minutes. 

 It is the same qualitatively as that of the grains of White Kaffir corn. 



I GV T P I r ,v 



Chart No. 



T a 



Curve of Reaction-Intensities of Starch of Andropogon 

 sorghum var. (Shallu). 



The stain 



