434 



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



shifting of the longitudinal axis of the primary lamellse 

 producing a curvature at one end of the grain; (2) 

 to nipple-like, large, rounded, or finger-like protuberances 

 at various points. The grains tend to be somewhat 

 broader and to have more rounded ends than those noted 

 under H. leathering. The conspicuous forms are pointed 

 and pure ovoid, elliptical, plano-convex, and nearly round. 

 There are also scalene-triangular, reniform, pyriform, 

 and irregularly quadrilateral forms. 



The hilum is a moderately distinct, small, round, or 

 lenticular spot, and often fissured. It is more distinct 

 and much more frequently fissured than in H. leathering. 

 The fissures take the following forms : (1) An irregularly 

 shaped cavity from which small fissures radiate; (2) a 

 single, short, straight or slightly convex line with some 

 small fissures branching from it, lying transversely or 

 longitudinally; (3) irregularly V- and Y-shaped; (4) 

 flying-bird form. The hilum may be either centric or 

 eccentric. The range of eccentricity is from 0.45 to 0.15 

 usually 0.35 of the longitudinal axis about the same as 

 in H. katherince. 



The lamellce are usually rather indistinct, though less 

 indistinct than in H. katherince, and when they can be 

 seen they are rather fine, continuous lines, circular, 

 ovoid, or lenticular in form when near the hilum, and 

 taking the form of the outline of the grain elsewhere. 

 There is often one broad refractive lamella which may 

 be situated at varying distances from the hilum. From 

 12 to 30, usually about 20, may be counted on the larger 

 grains. 



The size of the grains varies from the smaller which 

 are 3 by 3/, to the larger broad forms which are 48 by 

 40/x, and the larger narrow forms which are 50 by 38^, 

 in length and breadth. The common sizes are 34 by 30/i 

 and 32 by 20/*. The grains of this starch are larger and 

 tend to be somewhat broader in proportion to their length 

 than those of H. katherince. 



POLARISCOPIC PROPERTIES. 



The figure varies from centric to quite eccentric, more 

 of the former than in H. katherince, and the figure is 

 usually distinct and clean-cut, more so than in H. kath- 

 erince. The lines vary from fine to moderately coarse, 

 with more of the former ; the mean being finer than in 

 H. katherince. In the majority of grains the lines inter- 

 sect obliquely, but the intersection is at right angles in 

 a considerable number; more of the latter than in H. 

 katherince. The lines are also not infrequently arranged 

 as a median line with bisected ends, more of this type 

 being observed than in H. katherince. The lines are more 

 frequently straight, but they are occasionally bent and 

 moderately, of ten bisected; they are less frequently bent, 

 but the bisection is about the same as in H. katherince. 

 Compound and multiple figures are not uncommon, but 

 more numerous than in 3. katherince. 



The degree of polarization is very high (value 90). 

 The polarization varies from high to very high in the 

 different grains, and there is some variation in the same 

 aspect of a given grain, the variation both in the former 

 and the latter is less common than in H. katherince, and 

 hence the degree of polarization is much higher than in 

 H. katherince. 



With selenite the quadrants are usually well defined, 

 more frequently unequal in size and generally regular in 



shape ; the definition is sharper ; they are more often equal 

 in size, and the regularity is much greater than in H. 

 katherince. The colors are generally pure, the purity not 

 so marked in the yellow as in the blue; the impurity 

 results more frequently from an extremely high degree 

 of polarization which imparts a greenish tinge to both 

 colors ; the colors are more frequently pure, although the 

 type of impurity above described is not present in H. 

 katherince. 



IODINE REACTIONS. 



With 0.25 Lugol's solution the grains color a mod- 

 erate violet (value 50), which is a little more bluish 

 and deeper than in H. katherince; the color deepens more 

 rapidly to a greater depth and becomes more blue than in 

 H. katherince. With 0.125 per cent solution the grains 

 color a light violet, a little deeper and more blue in tint 

 than in H. katherince, the color gradually deepens to a 

 moderate grade, a little deeper than in H. katherince. 

 (Studies of the iodine reactions were limited because of 

 insufficient material.) 



ANILINE REACTIONS. 



With gentian violet the grains color very faintly at 

 once, in half an hour becoming moderate to deep (value 

 55), some deeper than others, but not so deep as in H. 

 katherince. 



With safranin the grains color very lightly at once 

 and in half an hour they become moderate to deep (value 

 60), of about the same depth as in H. katherince. 



TEMPERATURE REACTIONS. 



The majority of the grains are gelatinized at 77 to 

 77.5 C.; and of all at 78 to 79, mean 78.5 C. 



EFFECTS OF VARIOUS REAGENTS. 



The reaction with chloral hydrate begins in a few 

 grains in 1 minute. Complete gelatinization occurs in 

 about 2 per cent of the entire number of grains and 4 

 per cent of the total starch in 5 minutes ; in about 8 per 

 cent of the grains and 14 per cent of the total starch in 

 15 minutes ; in about 11 per cent of the grains and 15 per 

 cent of the total starch in 30 minutes ; in about 14 per 

 cent of the grains and 17 per cent of the total starch in 

 45 minutes ; and little if any further change in 60 min- 

 utes. (Chart D 85.) 



A bubble appears at the hilum which expands to 

 greater size than in H. katherince. The fissure when 

 present becomes enlarged and refractive, which was not 

 observed in H. katherince. The lamellae do not generally 

 become more distinct, though slightly more frequently 

 than in H. katherince. A well-defined refractive border 

 is formed, and a very distinct lamella frequently consti- 

 tutes a line of demarcation between the main body of the 

 grain and the refractive border, the latter being much 

 more prominent than in H. katherince. In some grains 

 gelatinization may begin and proceed as in H. katherince, 

 but in others it begins at one point in the border and 

 spreads around the grain, and occasionally progresses 

 rather quickly through the mesial region, the refractive 

 border proving the more resistant. The starch is some- 

 times disorganized with the appearance of refractive frag- 

 ments or granules, the latter often being observed at an 

 earlier stage in the process of gelatinization than in H. 

 katherince. Deep, short fissures may form in the most 

 resistant part of the grain previous to gelatinization, and 



