IRIS. 



661 



18 per cent of the grains and 60 per cent of the total 

 starch in 45 minutes; in about 21 per cent of the grains 

 and 63 per cent of the total starch in 60 minutes. (Chart 

 D439.) 



The reaction with barium chloride begins in a few 

 grains in 1 minute. Complete gelatinization occurs in 

 less than 0.5 per cent of both the grains and total starch 

 in 5 minutes; in less than 0.5 per cent of the grains and 

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

 0.5 per cent of the grains and 3 per cent of the total starch 

 in 30 minutes; in about 1 per cent of the grains and 

 4 per cent of the total starch in 45 minutes; in about 

 1 per cent of the grains and 5 per cent of the total starch 

 in 60 minutes. (Chart D440.) 



The reaction with mercuric chloride begins in rare 

 grains in 1 minute. Complete gelatinization occurs in 

 less than 0.5 per cent of the entire number of grains and 

 total starch in 5 minutes; in about 0.5 per cent of the 

 grains and 5 per cent of the total starch in 15 minutes ; 

 in about the same percentage of the grains and 9 per cent 

 of the total starch in 30 minutes; in about 1 per cent 

 of the grains and 10 per cent of the total starch in 45 

 minutes; in about 2 per cent of the grains and 14 per 

 cent of the total starch in 60 minutes. (Chart D 441.) 



Iris mrs. alan grey (Hybrid). 



(Plate 19, fig. Ill; Charts D 421 to D 441.) 

 Histologic Properties. 



In form the grains are usually simple and isolated. 

 There are, however, as many compound grains and aggre- 

 gates as in I. pallida queen of may, and both belong to the 

 same types which are described under that starch. The 

 grains are more regular in form than in either parent, 

 in this respect more closely resembling J. cengialti than 

 I. pallida queen of may. The irregularities which occur 

 are due to the same causes, and in the same order of fre- 

 quency of occurrence as in J. cengialti. The conspicuous 

 forms are elongated and broad elliptical with flattened 

 distal end, ovoid, and nearly round. The additional 

 forms are boot-shaped, rod-shaped, and pyriform. The 

 grains are not flattened. 



In form the grains of I. mrs. alan grey show, on the 

 whole, a somewhat closer relationship to I. cengialti than 

 to /. pallida queen of may. The three starches resemble 

 one another closely. 



The hilum is moderately distinct and is even less 

 often fissured than in I. pallida queen of may. The 

 fissures have the same forms as in that starch. The 

 hilum is eccentric from 0.4 to 0.1, usually 0.19, of the 

 longitudinal axis. 



In the character of the hilum J. mrs. alan grey shows 

 a closer resemblance to I. pallida queen of may. The 

 hilum is more eccentric (0.1 of the longitudinal axis) 

 than I. pallida queen of may, and is still more eccentric 

 (0.06 of the longitudinal axis) than in I. cengialti, there- 

 fore closer to I. pallida queen of may. 



The lamella? are less distinct than in either parent, 

 in this resembling I. cengialti more closely than /. pallida 

 queen of may. Otherwise they are the same as in I. 

 cengialti. The entire number on the grains can not 

 be determined. 



In size the grains vary from the smaller grains which 

 are 3 by 3,u, to the larger which are 22 by 10/*, in length 

 and breadth. The common sizes are 10 by 8fi and 10 by 



6;u. I. mrs. alan grey is smaller than either parent, hut 

 is closer to /. pallida queen of may than to I. ccngialli. 

 The large-sized grains are 2//, shorter but no narrower 

 than those of I. pallida queen of may and 8/«. shorter 

 and 6/x narrower than those of I. cengialti. The common 

 sizes are 4/x shorter but are 2/* wider than those of /. mrs. 

 alan grey, and are 12;u shorter and 4/u. narrower than 

 those of I. cengialti. 



PotARiscoric Properties. 



The figure is not so distinct nor so well defined as in 

 either parent, but in this respect resembles I. pallida 

 queen of may more closely than I. cengialti. The lines 

 cross at right angles as in some grains of I. pallida queen 

 of may, or at a very acute angle which, as in I. pallida 

 queen of may, does not vary much in size in different 

 grains. They are as much bent and as often bisected as 

 in I. pallida queen of may. The figure is as frequently 

 in the form of a conjugate hyperbola or of a long line 

 bisected at both ends as in that starch. 



The degree of polarization varies from low to high 

 (value 45), 5 units less than in I. pallida queen of may 

 and 15 units less than in I. cengialti. There are fewer 

 grains in which it is high, and more in which it is low 

 or low to moderate, than in either parent. There is 

 usually some variation in a given aspect of an individual 

 grain. 



With selenite the quadrants are not so clear-cut as 

 in either parent, but are closer in this respect to I. pallida 

 queen of may than to I. cengialti. They are as irregular 

 in form as in 7. pallida queen of may. The colors are 

 somewhat more often impure than in either parent. 



In the character of the figure, the degree of polariza- 

 tion, and the appearance with selenite I. mrs. alan grey 

 shows a closer relationship to I. pallida queen of may 

 than to I. cengialti. 



Iodine Reactions. 

 With 0.25 per cent Lugol's solution the grains all 

 color a moderate violet tinged with blue (value 50), 5 

 units more than in I. cengialti and 15 units more than 

 in I. pallida queen of may. With 0.125 per cent Lugol's 

 solution the grains all color a light violet, more than in 

 either parent but closer to I. cengialti than to I. pallida 

 queen of may. The qualitative reactions are closer to 

 those of /. cengialti. 



Aniline Reactions. 



With gentian violet the grains all color very lightly 

 at once, and in half an hour they are light to moderately 

 colored (value 40), 5 units less than in I. cengialti and 

 8 units less than in I. pallida queen of may. 



With safranin the grains all color very lightly at 

 once, and in half an hour they are moderately colored 

 (value 45), 5 units less than in I. cengialti and 7 units 

 less than in I. pallida queen of may. 



In the reactions with aniline stains I. mrs. alan grey 

 shows a closer relationship to /. cengialti than to I. pal- 

 lida queen of may. 



Temperature Reactions. 

 The temperature of gelatinization of the majority 

 of the grains is 69° to 70° C, and of all is 73° to 

 74.5° C, mean 73.75° C. The temperature of gela- 

 tinization of 1. 7iirs. alan grey is 1.6° C. less than that of 



