644 



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



per cent of the total starch in 45 minutes ; little if any 

 further advance in 60 minutes. (Chart D 395.) 



The reaction with copper nitrate begins in a few 

 grains in 30 seconds. Complete gelatinization occurs in 

 less than 0.5 per cent of the entire number of grains 

 and 16 per cent of the total starch in 5 minutes; in 

 about 1 per cent of the grains and 25 per cent of the 

 total starch in 15 minutes; in about 17 per cent of the 

 grains and 70 per cent of the total starch in 30 minutes ; 

 in about 25 per cent of the grains and 76 per cent of the 

 total starch in 45 minutes ; in about 34 per cent of the 

 grains and 81 per cent of the total starch in 60 minutes. 

 (Chart D 396.) 



The reaction with cupric chloride begins in a few 

 grains immediately. Complete gelatinization occurs in 

 about 3 per cent of the entire number of grains and 15 

 per cent of the total starch in 5 minutes; in about 10 

 per cent of the grains and 50 per cent of the total starch 

 in 15 minutes; in about 27 per cent of the grains and 

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

 34 per cent of the grains and 77 per cent of the total 

 starch in 45 minutes ; in about 39 per cent of the grains 

 and 81 per cent of the total starch in 60 minutes. 

 (Chart D 397.) 



The reaction with barium chloride begins in a few 

 grains in 1 minute. Complete gelatinization occurs in 

 less than 0.5 per cent of the entire number of grains 

 and 1 per cent of the total starch in 5 minutes ; in about 

 2 per cent of the grains and 6 per cent of the total starch 

 in 15 minutes; in about 3 per cent of the grains and 

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

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

 total starch in 45 minutes; in about 3 per cent of the 

 grains and 11 per cent of the total starch in 60 minutes. 

 (Chart D398.) 



The reaction with mercuric chloride begins in a few 

 grains in 1 minute. Complete gelatinization occurs in 

 about 1 per cent of the entire number of grains and 6 

 per cent of the total starch in 5 minutes ; in about 3 per 

 cent of the grains and 18 per cent of the total starch in 

 15 minutes; in about 10 per cent of the grains and 32 

 per cent of the total starch in 30 minutes; in about 20 

 per cent of the grains and 40 per cent of the total starch 

 in 45 minutes; in about 20 per cent of the grains and 

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

 D399.) 



IRIS ISMALI (HYBRID). 



(Plate 18, fig. 105; Charts D 379 to D 390.) 



HISTOLOQIC PROPERTIES. 



In form the grains are usually simple and isolated, 

 and there are not so many aggregates of 2 or 3 com- 

 ponents as in either parent, but many more compound 

 grains than in /. iberica and a few more than in I. tro- 

 jana. The compound grains are of the two types already 

 described under /. iberica. The grains are much more 

 irregular than in I. iberica and somewhat more than in 

 /. trojana, and the irregularities are due to the following 

 causes, in their order of frequency of occurrence: (1) 

 Depressions and elevations in the surface giving an undu- 

 lating or wavy outline to the grain; (2) a secondary 

 set of lamellae whose longitudinal axis is at an angle, 

 usually a right angle, with that of the primary set; (3) 



deviation of the axis of the grain with a consequent 

 bending, usually at the middle; (4) rounded protuber- 

 ances from the sides or either end; (5) rarely, a shallow 

 notch in the distal margin. The conspicuous forms are 

 round and nearly round, elongated elliptical with flat- 

 tened distal end, and irregular rather broad ovoid with 

 rounded distal end. The additional forms are pyri- 

 form, boot-shaped, napiform, triangular, and irregularly 

 quadrilateral with rounded angles. The grains, as in 

 the parents, are not flattened. In form I. ismali shows 

 a closer relationship to /. iberica, than to 7. trojana. 



The hilum is as distinct as in 7. iberica and is even 

 less frequently fissured than in that starch, and when 

 fissures occur they are of the same character as noted 

 in I. iberica. The hilum is eccentric from 0.33 to 

 0.16, usually 0.23, of the longitudinal axis. In the 

 character of the hilum I. ismali shows a closer relation- 

 ship to I. iberica, but in the degree of eccentricity to 

 7. trojana; the latter being 0.08 less eccentric than in 

 7. iberica and 0.05 less eccentric than in 7. trojana. 



The lamellae are less distinct and are not so coarse 

 as in 7. iberica, and can not be demonstrated on all 

 the grains. They have the same arrangement as in 

 7, ib erica, but are not so apt to be irregular. The num- 

 ber counted on some of the larger grains varies from 

 6 to 10, usually 8, less than in either parent. 



In character, arrangement, and number of the la- 

 mellze, I. ismali shows a closer relationship to I. iberica 

 than to 7. trojana. 



In size the grains vary from the smaller which are 

 2 by 2jti, to the larger which are 22 by 10/t, in length and 

 breadth. The common sizes are 14 by lO^i and 14 by 12/*. 

 In size 7. ismali is much smaller than either parent, the 

 common sizes being 6/t shorter by 4/A narrower, or 6/i 

 shorter by 2/t narrower, than in 7. iberica, and 14/* 

 shorter by 8^. narrower, and 16/* shorter by 4/j, narrower, 

 than in 7. trojana. It is therefore closer to 7. iberica 

 in size than to 7. trojana. 



POIARISCOPIC PROPERTIES. 



The figure is somewhat less distinct and less well 

 defined than in either parent, in this showing a closer 

 relationship to 7. trojana than to 7. iberica. The lines as 

 in 7. trojana cross at a very acute angle which does not 

 vary greatly in size in the different grains. They are 

 somewhat less irregular than in 7. trojana and some- 

 what more than in 7. iberica. 



The degree of polarization varies from low to moder- 

 ately high (value 40), 10 units lower than in 7. trojana 

 and 5 units lower than in 7. iberica. There is less varia- 

 tion in a given aspect of an individual grain than in 

 either parent. In this respect the hybrid is closer to 

 7. iberica than I. trojana. 



With selenite the quadrants are less clear-cut than in 

 either parent, in this respect more closely resembling 

 7. trojana. They are as unequal in size and less irregu- 

 lar in form than in 7. trojana and more irregular than 

 in 7. iberica. The colors are less pure than in either 

 parent, in this respect more closely resembling 7. trojana 

 than 7. iberica. 



In the character of the figure and the appearance 

 with selenite 7. ismali shows a closer relationship to 

 7. trojana, and in the degree of polarization to 7. iberica. 



