648 



DATA OF PROPERTIES OF STARCHES OF PARENT- AND HYBRID-STOCKS. 



outline of the grain. They often show some irregulari- 

 ties, the chief of which is a small notch or depression 

 corresponding to the notch in the distal margin which is 

 noted in some of the grains. There is frequently one 

 coarse, moderately refractive lamella placed either at 

 about half the distance between the hilum and the distal 

 margin or very near the distal margin. The number 

 of lamellfe counted on the larger grains varies from 

 10 to 20, usually 15. 



In size the grains vary from the smaller which are 

 3 by 3,u, to the larger which are 30 by 16/*, in length 

 and breadth. The common sizes are 22 by 14/i and 20 

 by 18/,. 



Comparison of the histologic properties between 7. 

 iberica and I. cengialti shows: 



Form. There are more compound gTains and more 

 aggregates than in 7. cengialti. The compound grains 

 belong to two types neither of which is the same as the 

 one type seen in I. cengialti. In the first, 2 small 

 grains, each consisting of a hilum and 1 or 2 lamellae, are 

 adherent and surrounded by 8 to 15 common secondary 

 lamellfe, so that they are at the proximal end of a large 

 elongated grain. In the second type, 2 or 3 small 

 grains, if they are pyramidally arranged, each consisting 

 of a hilum and 4 or 5 lamellae, are surrounded by 1 or 2 

 common secondary lamellae. The grains are not quite 

 so regular in form, and the irregularities are due to the 

 same causes as in I. cengialti, with the addition of one 

 other — sharply defined, triangular depressions in the 

 margin at the side, probably representing pressure facets. 

 Elongated elliptical grains are more common and ovoid 

 forms very much less common than in 7. cengialti. 



The hilum is more distinct than in I. cengialti. It is 

 much less often fissured and the fissures have only the 

 first two forms mentioned in that starch. The hilum 

 is usually eccentric 0.15 of the longitudinal axis, 0.1 

 more than that of I. cengialti. 



The lamella are less distinct, not quite so coarse, 

 and more numerous, than in I. cengialti. Their general 

 arrangement is the same as in that starch. 



In size the grains are somewhat smaller though there 

 is no very marked difference between the two starches in 

 this respect. The common size is 20 by 14/t, 2/i shorter 

 and the same breadth, and the same length and 4/i 

 narrower, respectively, than the two common sizes of 

 J. cengialti. 



Polariscopic Properties. 



The figure is distinct and usually well defined. The 

 lines cross at a right angle or at an acute angle which 

 varies widely in different grains. They are usually not 

 bent, but not infrequently are bisected. 



The degree of polarization varies from moderately 

 high to high (value 60). There is usually but little 

 variation in a given aspect of the same grain. 



With selenite the quadrants are commonly clear-cut. 

 They are very unequal in size but generally regular in 

 form. The colors are, as a rule, pure and in an occasional 

 grain they have a greenish tinge. 



Comparison of the polariscopic properties between 

 I. iberica and 7. cengialti shows : 



The figure is not quite so distinct and is not so well 

 defined as in 7. cengialti. The lines rarely cross at a 

 right angle, but usually at an acute angle which does 

 not vary so much in size in different grains as in I. cen- 



gialti. They are more often bent and less often bisected 

 than in that starch. 



The degree of polarization varies from low to high 

 (value 50), 10 units lower than in I. cengialti. There 

 is also more variation in a given aspect of the individual 

 grains than in that starch. 



With selenite the quadrants are not quite so clear- 

 cut. They are as unequal in size, but are more often 

 irregular in shape than in J. cengialti. The colors 

 are usually not pure, while in I. cengialti they are pure. 



Iodine Reactions. 



With 0.25 per cent Lugol's solution the grains all 

 color a moderate violet tinged with blue (value 45) 

 and the color deepens rapidly until it is very deep and 

 has assumed more of a bluish tint. With 0.125 per cent 

 Lugol's solution, the grains all color a light violet and 

 the color deepens rapidly until it is deep and has assumed 

 more of a bluish tint. After heating in water until all 

 the grains are completely gelatinized and then treating 

 with a 2 per cent Lugol's solution the gelatinized grains 

 all color a moderate indigo, and the solution a very deep 

 indigo. If the preparation is boiled for 2 minutes and 

 then treated with an excess of a 2 per cent Lugol's solu- 

 tion most of the grain-residues are colored a light to 

 moderately light indigo at their proximal ends only, 

 the capsules reddish-violet and the solution a very deep 

 indigo, deeper than after merely heating in water. 



Comparison of the iodine reactions bet*ween I. iberica 

 and 7. cengialti shows : 



With 0.25 per cent Lugol's solution, the grains all 

 color a light to moderate violet tinged with blue (value 

 40), 5 units less than in 7. cengialti. With 0.125 per 

 cent Lugol's solution they are colored more lightly than 

 with 7. cengialti. After heating in water until the 

 grains are completely gelatinized the grains are more and 

 the solution less deeply colored. After boiling for 2 

 minutes and then treating with an excess of a 2 per cent 

 Lugol's solution, the grain-residues are more often and 

 less lightly colored ; the capsules less deeply colored and 

 the color is reddish violet instead of wine-red; the 

 solution is very deeply colored, but not so deeply as in 

 7. cengialti. 



Aniline Reactions. 



With gentian violet the grains all color very lightly 

 at once, and in 30 minutes they are moderately colored 

 (value 45). About half of the grains are moderately to 

 deeply stained, and the other half light to moderately 

 stained. 



With safranin the grains all color very lightly at 

 once, and in 30 minutes they are moderately colored 

 (value 50) more than with gentian violet. A few of 

 the grains are light to moderately colored, and the rest 

 are moderately colored. There is much less variation 

 than with gentian violet. 



Comparison of the aniline reactions between 7. iberica 

 and 7. cengialti shows : 



With gentian violet the grains color moderate to 

 lightly (value 40), 5 units less than with 7. cengialti. 

 There is much less variation between different grains 

 than in 7. cengialti. 



With safranin the grains color moderately (value 

 45), 5 units less than in 7. cengialti. There is less 

 variation between different grains than in 7. cengialti. 



