592 



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



(1) Large or small pointed or rounded protuberances 

 from the sides or either end; (2) small, irregular de- 

 pressions and elevations of the surface and margin; (3) 

 a greater development of one part of the distal end or of 

 one side than the rest; (4) irregular and poorly denned 

 pressure facets; (5) a deviation of the long axis at either 

 end, with a consequent bending of the grain. The con- 

 spicuous forms are ovoid, lenticular, nearly round, dome- 

 shaped, plano-convex, and elliptical. There are also 

 clam-shell-shaped, round, reniform, pyrif orm, irregularly 

 quadrilateral, and triangular with rounded angles. The 

 broader forms are somewhat flattened, the others are not. 



The hilum, when it is not fissured, is a rather indis- 

 tinct, small, round, or lenticular spot. It is usually fis- 

 sured, but not deeply nor extensively, and the fissures 

 have the following forms: (1) Y- or T-shaped; (2) a 

 single short, straight or curved line lying transversely, 

 obliquely, or longitudinally; (3) an irregularly stellate 

 arrangement of several fissures; (4) a flying-bird form. 

 The hilum is often centric, but in the majority of the 

 grains it is eccentric from 0.44 to 0.31, usually 0.4, of 

 the longitudinal axis. 



The lamella are usually not visible, but in a few 

 grains they are moderately distinct and appear as rather 

 fine continuous rings which have in general the form 

 of the outline of the grain. They are more distinct near 

 the hilum than the margin, except in those grains which 

 have both primary and secondary starch, and in such 

 grains, when they can be seen at all, they can only be 

 found in the secondary starch. The total number can not 

 be determined on any grain. 



In size the grains vary from the smaller which are 

 3 by 3/t, to the larger elongated forms which are 36 by 

 28/*, and the larger broad forms which are 30 by 40/a, 

 rarely, 30 by 50/i, in length and breadth. The common 

 sizes are 28 by 20/t and 24 by 30/i. 



Comparison of the histologic properties between N. 

 triandrus albus and N. emperor shows: 



There are more compound grains and a few more 

 aggregates than in N. emperor and the compound grains 

 belong to the same two types that were described under 

 N. emperor, the only exception being that these grains 

 may have more components. No aggregates of com- 

 pound grains and simple grains, or of compound grains 

 only, are seen. There are not so many simple grains 

 which show a primary and a secondary starch formation. 

 The grains are more irregular than in N. emperor, and 

 the irregularities are due to the same causes, except that 

 pressure facets are not seen on these grains. The grains 

 are not so varied in form as in N. emperor. 



The hilum when not fissured is no more distinct 

 than in N. emperor, but it is more often and somewhat 

 more deeply and extensively fissured than in that starch. 

 The fissures have the same forms, except that a cruciate 

 figure is frequently seen. The hilum is more eccentric, 

 the usual degree of eccentricity being 0.33 of the longi- 

 tudinal axis. 



The lamella? are somewhat more often visible and 

 when so are somewhat more distinct. They are not quite 

 so fine, and when near the hilum do not follow the form 

 of the outline of the grain, but otherwise they resemble 

 those of N. emperor. 



In size the grains are not quite so large as those of 

 N. emperor, though the differences are slight. 



Polariscopic Properties. 



The figure is usually distinct, but is commonly not 

 very well defined. The lines generally cross at right 

 angles, but sometimes cross at acute angles which do not 

 vary greatly in size in the different grains. They are, 

 as a rule, not bent, and rarely are bisected. The figure, 

 rarely, has the form of a conjugate hyperbola, or of a 

 long line bisected at both ends. 



The degree of polarization varies from low to high 

 (value 60). Most of the grains have a moderate or 

 moderate to high degree of polarization. There is some 

 variation in a given aspect of some of the individual 

 grains. 



With selenite the quadrants are usually not clear-cut, 

 and are unequal in size, and usually regular in shape. 

 The colors are often pure but sometimes not pure, the 

 yellow more often than the blue. In some of the grains 

 there is a greenish tinge. 



Comparison of the polariscopic properties between 

 N. triandrus albus and N. emperor shows : 



The figure is not so distinct, but is more often well 

 defined. The lines are less apt to cross at right angles, 

 and more apt to cross at acute angles which do not vary 

 much. They are, as in N. emperor, not often bent or 

 bisected, and there are the same number of grains in 

 which the figure has the form of a conjugate hyperbola, 

 or a long line bisected at both ends. 



The degree of polarization is lower than in N. emperor 

 (value 50), as there are fewer grains in which it is 

 moderate to high and high. 



With selenite the quadrants are more often clear-cut, 

 and are of the same regularity. The colors are less 

 often pure and there are fewer grains which have a 

 greenish tinge. 



Iodine Reactions. 



With 0.25 per cent Lugol's solution the grains all 

 color a moderate to deep violet tinged with blue (value 

 60), and the color deepens rapidly until very deep and 

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

 Lugol's solution the grains all color a light to moderate 

 violet, and the color deepens rapidly until it is very deep, 

 and has assumed a bluish tint. After heating in water 

 until all the grains are gelatinized and then treating 

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

 color a moderate indigo and the solution a deep indigo. 

 If the preparation is boiled for 2 minutes and then 

 treated with an excess of a 2 per cent Lugol's solution, 

 the grain-residues all color a light indigo, the capsules 

 a red or a reddish violet, and the solution a very deep 

 indigo-blue. 



Comparison of the iodine reactions between N. trian- 

 drus albus and N. emperor shows : 



With 0.25 per cent Lugol's solution the grains all 

 color more than those of N. emperor (value 65) ; so also 

 with 0.125 per cent Lugol's solution. After heating in 

 water until the grains are all gelatinized and then treat- 

 ing with a 2 per cent Lugol's solution, the gelatinized 

 grains and the solution color the same as in N. emperor. 

 If the preparation is boiled for 2 minutes and then treated 

 with an excess of a 2 per cent Lugol's solution, the 

 grain-residues, the capsules, and the solution all color 

 the same as in N. emperor. 



