754 



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



are much more often present than in M. vexillaria; as in 

 that species it could not be determined whether or not 

 they always represent depositions at different periods, 

 or whether they are caused by a shifting of the longi- 

 tudinal axis during 1 period. The number counted on 

 the larger grains varies from 26 to 38, more often 

 the former. 



The size of the grains varies from the smaller which 

 are 6 by 5fi, to the larger elongated, which are 40 by 30/*, 

 and the broadened 34 by 50^; the common size of the 

 elongated is about 30 by 24/x and of the broadened 24 

 by 26/t, in length and breadth. The size is larger than in 

 the other parent and with a marked tendency to 

 broadness. 



POLABISCOPIO PBOPERTIES. 



The figure is not quite as clean-cut as in M. vexillaria, 

 varies from centric to quite eccentric, with a smaller pro- 

 portion of the eccentric type than in M. vexillaria, thus 

 making the mean less eccentric. The lines vary from 

 fine to coarse, the mean being coarser than in M. vexil- 

 laria; they intersect as in M. vexillaria, but the arrange- 

 ment of a median line with bisected ends is more fre- 

 quent. The lines are more often bent than straight and 

 also frequently bisected; both occur with greater fre- 

 quency than in M. vexillaria. Double and multiple 

 figures of both the aggregate and the compound type are 

 present as in M. vexillaria. 



The degree of polarization is moderate to very high 

 (value 75), the mean being lower than in M. vexillaria 

 because the variation is greater, although somewhat more 

 of the very high grains are present than in M. vexillaria. 

 A greater variation is also found in the same aspect of a 

 given grain. 



With selenite the quadrants vary from moderately 

 to sharply defined, less clean-cut than in M. vexillaria; 

 they are generally unequal in size and vary from slightly 

 to very irregular in shape, more irregular than in M. 

 vexillaria. The blue is generally pure, but the yellow 

 is frequently not pure throughout the entire quadrant; 

 and the impurity is at both ends of the scale as in M. 

 vexillaria, but the proportion of the purplish and orange 

 is considerably greater, while that of the greenish tinge is 

 slightly greater, hence the mean places the impurity 

 of the colors lower than in M. vexillaria. 



Iodine Reactions. 

 With 0.25 per cent Lugol's solution the grains color 

 a moderate blue- violet (value 50), which, however, is a 

 little lighter and more reddish, than in M. vexillaria. 

 The color deepens rapidly but is more varied in depth of 

 the individual grains and also becomes neither so deep 

 nor so bluish as in M. vexillaria. With 0.125 per cent 

 Lugol's solution the grains color a light violet which is a 

 little lighter and more reddish than in M. vexillaria; the 

 color deepens with greater variation, and also becomes 

 neither so deep nor so bluish as in M. vexillaria. After 

 heating in water until all the grains are gelatinized and 

 then adding iodine, the gelatinized grains color a moder- 

 ately deep to deep blue, some with reddish tint, deeper 

 and a little more reddish than in M. vexillaria. The 

 solution becomes a deep indigo-blue, deeper and purer 

 than in M. vexillaria. If the preparation is boiled for 2 

 minutes and then treated with an excess of 2 per cent 

 Lugol's solution, the grain-residues (somewhat more 



numerous than in M. vexillaria) become a moderately 

 deep blue, all with reddish tint, deeper than in M. vexil- 

 laria; and the capsules vary from an amethyst or light 

 reddish-heliotrope to deep reddish-heliotrope or rarely 

 a wine-red — they are deeper and less reddish than in 

 M. vexillaria. The solution is a little deeper than in M. 

 vexillaria. 



Aniline Reactions. 



With gentian violet the grains immediately color very 

 lightly, and in 30 minutes they are moderate to moder- 

 ately deep in color (value 55), more of the latter than in 

 M. vexillaria, hence making the mean deeper. The 

 one lamella stains more deeply than the other parts of 

 the grain, as in M . vexillaria. 



With safranin the grains immediately color lightly, a 

 little deeper than with gentian violet, and in 30 minutes 

 they are moderate to deep in color (value 65), consider- 

 ably deeper than in M. vexillaria. The one lamella colors 

 more deeply with this reagent as with gentian violet. 



Temperature Reactions. 

 The temperature of gelatinization of the majority 

 of grains is at 74° to 76° C, and of all but rare resistant 

 grains at 76° to 77° C, mean 76.5° C. The central 

 portion of the grains of this species is much more easily 

 gelatinized than the marginal lamellae, as in M. vexillaria. 

 This mesial portion of practically all the large grains is 

 gelatinized at 67° to 69° C, mean 68° C, but several 

 small grains are little affected, as well as the marginal 

 lamellas of the large grains, at this temperature. 



Effects of Various Reagents. 



The reaction with chloral hydrate begins immediately. 

 Complete gelatinization occurs in about 50 per cent of the 

 grains and 60 per cent of the total starch in 5 minutes; 

 in about 66 per cent of the grains and 71 per cent of 

 the total starch in 15 minutes ; in about 81 per cent of the 

 grains and 82 per cent of the total starch in 30 minutes; 

 in about 76 per cent of the grains and 84 per cent of 

 the total starch in 45 minutes; little if any further 

 advance in 60 minutes. (Chart D 595.) 



The hilum is, usually, as distinct as in M. vexillaria, 

 but in some grains it is not distinct. The lamellas are 

 usually not distinct, but can be seen in some grains. A re- 

 fractive space is noted at the distal margin as in M. vexil- 

 laria, but it is not so broad or so refractive, as in those 

 grains. Gelatinization differing from M. vexillaria begins 

 at many points on the margin, or, as in M. vexillaria, it 

 begins at the distal margin and then at the proximal end. 

 The progress of gelatinization is much the same as in M. 

 vexillaria, except that it is more irregular, more granules 

 are formed and split off, and the greater part of the 

 grain may be split by fissures into several pieces which 

 gelatinize separately. The grains are large and more 

 distorted than those of M. vexillaria. 



The reaction with chromic acid begins immediately. 

 Complete gelatinization occurs in about 6 per cent of the 

 entire number of grains and 37 per cent of the total 

 starch in 5 minutes; in about 20 per cent of the grains 

 and 71 per cent of the total starch in 15 minutes ; in about 

 70 per cent of the grains and 96 per cent of the total 

 starch in 30 minutes; in about 95 per cent of the grains 

 and in over 99 per cent of the total starch in 45 minutes. 

 (Chart D 596.) 



