IRIS. 



671 



of the entire number of grains and 46 per cent of the 

 total starch in 5 minutes; in about 54 per cent of the 

 grains and 86 per cent of the total starch in 15 minutes; 

 in about 74 per cent of the grains and 90 per cent of the 

 total starch in 30 minutes; in about 83 per cent of the 

 grains and 95 per cent of the total starch in 45 minutes ; 

 in about 88 per cent of the grains and 97 per cent of the 

 total starch in 60 minutes. (Chart D 455.) 



The reaction with uranium nitrate begins in a few 

 grains immediately. Complete gelatinization occurs in 

 about 5 per cent of the entire number of grains and 47 

 per cent of the total starch in 5 minutes; in about 60 

 per cent of the grains and 86 per cent of the total starch 

 in 15 minutes; in about 71 per cent of the grains and 

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

 83 per cent of the grains and 97 per cent of the total 

 starch in 45 minutes ; in about 86 per cent of the grains 

 and 98 per cent of the total starch in 60 minutes. 

 (Chart D 456.) 



The reaction with strontium nitrate begins imme- 

 diately. Complete gelatinization occurs in about 10 per 

 cent of the entire number of grains and 45 per cent of 

 the total starch in 5 minutes ; in about 74 per cent of the 

 grains and 93 per cent of the total starch in 15 minutes; 

 in about 95 per cent of the grains and 98 per cent of the 

 total starch in 30 minutes. (Chart D 457.) 



The reaction with cobalt nitrate begins in 30 seconds. 

 Complete gelatinization occurs in about 2 per cent of the 

 entire number of grains and 12 per cent of the total 

 starch in 5 minutes ; in about 15 per cent of the grains 

 and 40 per cent of the total starch in 15 minutes; in 

 about 20 per cent of the grains and 50 per cent of the 

 total starch in 30 minutes ; slight advance in 45 minutes ; 

 in about 24 per cent of the grains and 51 per cent of the 

 total starch in 60 minutes. (Chart D 458.) 



The reaction with copper nitrate begins immediately. 

 Complete gelatinization occurs in about 26 per cent of the 

 entire number of grains and 58 per cent of the total 

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

 and 86 per cent of the total starch in 15 minutes; in 

 about 78 per cent of the grains and 96 per cent of the 

 total starch in 30 minutes ; in about 82 per cent of the 

 grains and 96 per cent of the total starch in 45 minutes ; 

 in about 89 per cent of the grains and 98 per cent of the 

 total starch in 60 minutes. (Chart D 459.) 



The reaction with cupric chloride begins imme- 

 diately. Complete gelatinization occurs in about 24 

 per cent of the entire number of grains and 64 per cent 

 of the total starch in 5 minutes ; in about 64 per cent of 

 the grains and 95 per cent of the total starch in 15 

 minutes; in about 80 per cent of the grains and 98 per 

 cent of the total starch in 30 minutes; in about 92 pur 

 cent of the grains and in more than 99 per cent of the 

 total starch in 45 minutes. (Chart D 460.) 



The reaction with barium chloride begins imme- 

 diately. Complete gelatinization occurs in about 2 per 

 cent of the entire number of grains and 10 per cent of 

 the total starch in 5 minutes ; in about 6 per cent of the 

 grains and 37 per cent of the total starch in 15 minutes ; 

 in about 13 per cent of the grains and 51 per cent of the 

 total starch in 30 minutes; in about 27 per cent of the 

 grains and 58 per cent of the total starch in 45 minutes ; 

 in about 34 per cent of the grains and 68 per cent of 

 the total starch in 60 minutes. (Chart D 461.) 



The reaction with mercuric chloride begins imme- 

 diately. Complete gelatinizatiou occurs in about 5 per 

 cent of the entire number of grains and 34 per cent of 

 the total starch in 5 minutes; in about 50 per cent of 

 the grains and 80 per cent of the total starch in 15 

 minutes; in about 75 per cent of the grains and 88 per 

 cent of the total starch in 30 minutes; in about 83 per 

 cent of the grains and 95 per cent of the total starch in 

 45 minutes ; in about 88 per cent of the grains and 96 

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

 D462.) 



A larger percentage of grainsi becomes completely 

 gelatinized than in /. persica var. purpurea, but there 

 are more scattered entire grains which resist the reac- 

 tion for a longer period, hence the variation between the 

 percentage. 



IRIS PDRSIND (HYBRID). 



(Plate 19, fig. 114; Charts D 442 to 462.) 

 HISTOLOGIO PBOPEBTIES. 



In form the grains are usually simple and isolated. 

 There are a few aggregates as in the parents, and even 

 fewer compound grains than in I. persica var. purpurea, 

 and all are of the same types as those described under 

 /. persica var. purpurea. The grains are not so irregular 

 as in I. persica var. purpurea and are slightly more 

 irregular than in I. sindjarensis, and the irregularities 

 are due to the following causes : ( 1 ) Pointed and rounded 

 protuberances of various sizes; (2) small, shallow de- 

 pressions and elevations on the surface, giving an undu- 

 lating outline to the margin; (3) a notch in the middle 

 of the distal margin; (4) rarely, deviation of the longi- 

 tudinal axis. The conspicuous forms are both slender 

 and broad ovoid, and lenticular. The additional forms 

 are nearly round, elliptical, irregularly quadrilateral, 

 dome-shaped, and triangular. The grains are not flat- 

 tened. In form this starch shows a closer relationship to 

 7. persica var. purpurea than to I. sindjarensis. 



The hilum when not fissured is as distinct as in 

 7. persica var. purpurea, and it is usually fissured, even 

 more often and more extensively than in I. persica var. 

 purpurea and the types of fissuring are the same as in 

 I. persica var. purpurea . The hilum is sometimes cen- 

 tric as in the parents, but is commonly eccentric from 

 0.44 to 0.26, usually 0.32, of the longitudinal axis. 

 The hilum is 0.01 more eccentric than that of I. sind- 

 jarensis, and 0.03 more eccentric than that of 7. persica 

 var. purpurea. In the character of the hilum 7. pursind 

 is closer to I. persica var. purpurea than to I. sindjarensis, 

 but in the degree of eccentricity it is closer to 7. sind- 

 jarensis than to 7. persica var. purpurea. 



The lamellce are not as distinct as in either parent, 

 and can not be demonstrated in many grains. When 

 visible, they appear as continuous, rather coarse rings 

 which are circular near the hilum, and have the form 

 of the outline of the grain near the margin. The num- 

 ber counted on the larger grains varies from 5 to 12, 

 usually 8. 



In the character and the number of the lamellae 7. 

 pursind shows a closer relationship to 7. persica var. 

 purpurea than to 7. sindjarensis. 



In size the grains vary from the smaller which are 

 2 by 2/*, to the larger elongated forms which are 40 by 

 24/i, and the larger broad forms which are 42 by 34/*, 



