GENUS ZEA. 



349 



Chart No. 5. 



CA PA rc P S CI PA CA 



PC PS 



The grains vary in size from the smaller, which are 4 by 4/i, to the larger, which are 20 by 16/i 

 or 20 by 20//. The common size is 14/t. 



Polariscopic Properties. — The figure is usually centric, distinct, regular, and fairly clear-cut. 

 The lines become broader near the margin, not infrequently slightly curved, and generally placed 

 at right angles to one another. 



The degree of polarization is fairly high. It does not vary much in different grains, nor in dif- 

 ferent aspects of the same grain. It is higher in Golden Queen. 



With selenite the quadrants are usually well defined, irregular in shape, and unequal in size. 

 The colors are generally pure. 



Iodine Reactions. — With a 0.25 per cent Lugol's solution the grains all color a fairly deep violet; 

 and with a 0.125 per cent solution they color lightly and the shade does not deepen rapidly. The 

 color is a little deeper than in Golden Queen. After 

 heating in water until all the grains are completely gel- 

 atinized, the solution colors fairly and the gelatinized 

 grains very deeply on the addition of iodine. After boil- 

 ing for 2 minutes the solution colors very deeply, but the 

 gelatinized grain-residues not at all. The capsules all 

 color red-violet with an excess of iodine. 



Staining Reactions. — With gentian triolet the grains 

 when viewed in masses show a slight tint of violet at 

 once. After remaining in the solution for 30 minutes 

 they are unevenly and still lightly stained. If the fis- 

 sures at the hilum are quite broad the color is deeper at 

 this point. The color is the same as in Golden Queen. 



The grains, when viewed in masses, show a slight 

 tint of pink with safranin. After remaining in the solu- 

 tion for 30 minutes they are unevenly and still lightly 

 stained. The color is deeper than in Golden Queen. 



Temperature Reaction. — The temperature of gela- 

 tinization is 66° to 67° C., mean 66.5°. 



Effects of Various Reagents. — With chloral hydrate- 

 iodine the grains begin to react at once; most of them are gelatinized in 23^ minutes and all in 10 

 minutes. The reaction is qualitatively the same as in Golden Queen. 



The reaction begins at once with chromic acid. A few grains are dissolved in a minute and all in 

 Z}/2 minutes. The reaction is qualitatively the same as in Golden Queen. 



The reaction with pyrogallic acid begins at once. A few grains are gelatinized in 30 seconds, and 

 all in 2 minutes with the exception of a few scattered grains (one in several hundred) in which the 

 reaction is complete in 33^ minutes. A bubble is formed in many of the grains at the hilum during 

 the process of gelatinization. The reaction is qualitatively the same as in Golden Queen. 



With ferric chloride the reaction begins at once. A few grains are gelatinized in a minute, 

 most in 5 minutes, and all in 12 minutes. The reaction is qualitatively the same as in Golden Queen. 



The reaction begins at once with Purdy's solution. A few grains are gelatinized in 2 minutes 

 and about one-fifth in 30 minutes, and there is little further change in an hour. The reaction is 

 qualitatively the same as in Golden Queen. 



STARCH OF ZEA MAYS VAR. INDENTATA (HICKORY KING). (Plate 1, figs. 1 and 2. Chart 6.) 



Histological Characteristics. — In fonn the grains are simple and isolated, with the exception of a 

 number of small aggregates consisting of from two to six or seven components, and some clumps. 

 There are usually from one to five or six pressure facets on each of the grains. The grains are gener- 

 ally irregular in outline, owing to irregularities caused by variation in the size, number, and position of 

 the facets. The conspicuous forms are the polygonal with usually five to six facets, round, oval, 

 and ovoid. There are some triangular and hemispherical or dome-shaped grains. 



The hilum is a rather indistinct, small or large round spot or irregularly shaped cavity, cen- 

 trally or slightly eccentrically situated. It is often fissured either by a large, irregular fissure, or 

 by a single short, straight line; or by three straight radiating lines. 



The lamell(B are not demonstrable. 



Curve of Reaction-Intensities of Starch of Zea mays 

 var. indentata (Early Learning). 



