682 



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



to 22, but on the component grains generally 10 to 14. 

 In the characters of the lamellae C. colvillei is midway 

 between the parents, but in number it exceeds those of 

 the parents. 



The size of the grains varies from the smaller isolated 

 ones, which are 4 by 3/*, to the larger permanently isolated 

 which are 30 by 30/*, the larger doublets which arc 44 

 by 30/i, and of the larger separated dome-shaped com- 

 ponents which are 28 by 28/*, in length and breadth. 

 The common size of the permanently isolated grains is 

 about 24 by 22'/*, of the doublet about 34 by 24/*, and of 

 the dome-shaped component about 24 by 23/*. In size 

 the grains of 67. covillci are closer to 67. cardinalis than 

 to 67. tristis. 



Polariscopic Properties. 



The figure varies from centric to quite eccentric, 

 the mean is slightly greater than in G. cardinalis, the 

 same as in G. tristis. The lines are fine and may inter- 

 sect at right angle or obliquely with more of the former 

 as in G. cardinalis, but they are not quite so often bent 

 and bisected, while they are finer and more often bent and 

 bisected than in G. tristis. Double and multiple figures 

 are moderately numerous, but not found as frequently 

 as in G. cardinalis, though much more numerous than in 

 G. tristis. 



The degree of polarization varies from high to very 

 high (value 80), with not quite so many grains showing 

 the latter as in 67. cardinalis, hence the mean is some- 

 what lower, but much higher than in G. tristis. A slight 

 variation may be found in the same aspect of a given 

 grain as in G. cardinalis, but less than in 67. tristis, while 

 variation in the different grains is as in 67. cardinalis, but 

 somewhat less than in G. tristis. 



With selcnile the quadrants are sharply defined and 

 often slightly unequal in size and irregular in shape, 

 but in the larger permanently isolated grains they are 

 more often equal and generally regular. The definition 

 of the quadrants is about the same, but the mean some- 

 what more equal and regular than in 67. cardinalis, while 

 the definition is sharper, and the quadrants more equal 

 and regular than in 67. tristis. The colors are generally 

 pure; although an occasional impurity due to a greenish 

 tinge of both colors is found, they are pure in somewhat 

 more grains than in 67. cardinalis and in considerably 

 more than in 67. tristis. 



In degree of polarization, in the character of the 

 figure, and in the reaction with selenite the grains of G. 

 colvillei are much closer to 67. cardinalis than to 67. 

 tristis. 



Iodine Reactions. 



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

 a moderate blue-violet (value 55), which is a little lighter 

 than in 67. cardinalis, and as in 67. tristis they deepen 

 rapidly, becoming more bluish in tint but not quite as 

 dark as in both parents and are less reddish in tint than 

 in 67. tristis. With 0.125 per cent Lugol's solution the 

 grains color a light blue-violet, a trifle lighter than in 

 67. cardinalis, and the same difference as noted with 

 0.25 per cent Lugol's solution with 67. tristis, they deepen 

 with the same variation, but the mean is not quite so dark 

 as in 67. cardinalis, while there is more variation, but 

 not so much depth of color as in 67. tristis. After heating 

 in water until all the grains are gelatinized and then 

 adding 2 per cent Lugol's solution, the majority of the 



gelatinized grains color light to moderate, with a few 

 moderately deep blue; the color is of the same tint and 

 depth as in 67. cardinalis, but lighter and purer than in 

 G. tristis; the solution becomes a moderately deep indigo- 

 blue, about the same as in both parents. If the prepara- 

 tion is boiled for 2 minutes and then treated with an 

 excess of 2 per cent Lugol's solution, the grain-residues 

 become a deep blue with reddish tint, and the capsules 

 a deep heliotrope to wine-red ; both of about the same 

 depth but slightly more reddish than in 67. cardinalis, 

 the grain-residues about the same depth, the mean of 

 the capsules somewhat deeper, but both not nearly so 

 reddish as in 67. tristis. The solution has the same depth 

 of color as in both parents. 



Qualitatively and quantitatively the reactions with 

 iodine are nearer to 67. cardinalis than to 67. tristis, and 

 the quantitative reactions are lower than in either parent. 



Aniline Reactions. 



With gentian violet the grains color very lightly at 

 once, and in half an hour they are moderately colored 

 (value 47), though slightly lighter than in 67. cardinalis, 

 but deeper than in 67. tristis. The delicate border of 

 deeper color of occasional grains was noted as in G. car- 

 dinalis ; this was not observed in 67. tristis. 



With safranin the grains stain lightly at once, and 

 in half an hour they are moderately colored (value 53), 

 though somewhat deeper than with gentian violet, the 

 same as in 67. cardinalis, but deeper than in 67. tristis. 

 The same delicate border of deeper color of occasional 

 grains is seen, as in the reaction with gentian violet, and 

 noted for 67. cardinalis, but not for 67. tristis. 



The reactions with aniline stains are much closer to 

 67. cardinalis than to G. tristis. 



Temperature Reactions. 

 The majority of the grains are gelatinized at 78° 

 to 80° C, and all at 82° to 83° C, mean 82.5° C. The 

 temperature of gelatinization is nearer to 67. cardinalis 

 (mean 85°) than to 67. tristis (mean 78.5°). 



Effects of Various Reagents. 



The reaction with chloral hydrate begins immediately. 

 Complete gelatinization occurs in about 11 per cent of 

 the entire number of grains and 17 per cent of the total 

 starch in 5 minutes; in about 21 per cent of the grains 

 and 25 per cent of the total starch in 15 minutes; in 

 about 28 per cent of the grains and 34 per cent of the 

 total starch in 30 minutes; in about 39 per cent of the 

 grains and 43 per cent of the total starch in 45 minutes; 

 in about 40 per cent of the grains and 44 per cent of 

 the total starch in 60 minutes. (Chart D 463.) 



The hilum becomes very prominent and usually a 

 small bubble is formed there, and two lines extend From 

 the hilum to the distal corners as in 67. cardinalis. The 

 lamella?, however, become distinct only on some of the 

 grains as in 67. tristis. Gelatinization begins and pro- 

 ceeds as in G. cardinalis, with the exception of a few 

 grains in which gelatinization begins all around the 

 margin as in 67. tristis. The gelatinized grains are large 

 and somewhat distorted but still retain some of the 

 original form of the grain. 



The process of gelatinization is qualitatively closer 

 to 67. cardinalis, except in a few grains in which it is 

 closer to G. tristis. 



