722 



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



this latter differing from the majority of grains in R. 

 albo-maculata. The progress of gelatinization from the 

 beginning of these various methods is the same as de- 

 scribed under R. albo-maculata. The gelatinized grains 

 are moderately large and somewhat distorted, but retain 

 much of their original form as in R. albo-maculata. 



The reaction with chromic acid begins in half a min- 

 ute. Complete gelatinization occurs in about 1 per cent 

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

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

 and G8 per cent of the total starch in 15 minutes ; in about 

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

 starch in 30 minutes ; in about 88 per cent of the grains 

 and 99 per cent of the total starch in 45 minutes; com- 

 plete gelatinization occurs with the exception of a portion 

 of the margin of rare grains and over 99 per cent of both 

 the grains and total starch in 60 minutes. (Chart 

 D546.) 



The hilum becomes distinct sooner than in R. albo- 

 maculata, but evidence of a lamellar structure is less 

 often seen than in that species. Gelatinization begins 

 at the hilum and the process is essentially the same as in 

 R. albo-maculata, except that the striae from the hilum 

 to the margin are not so marked, nor are cracks invading 

 the margin from without so often noted. 'Most of the 

 gelatinized grains persist, and few are seen to be com- 

 pletely dissolved. They are large and thin-walled as in 

 R. albo-maculata. 



The reaction with pyrogallic acid begins immediately. 

 Complete gelatinization occurs in about 1 per cent of 

 the entire number of grains and 2 per cent of the total 

 starch in 5 minutes ; in about 2 per cent of the grains and 

 3 per cent of the total starch in 15 minutes ; in about 3 

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

 in 30 minutes; in about 4 per cent of the grains and 

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

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

 total starch in 60 minutes. (Chart D 547.) 



The reaction with nitric acid begins in a few grains 

 immediately. 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 10 per cent of 

 the grains and 16 per cent of the total starch in 15 

 minutes; in about 10 per cent of the grains and 20 per 

 cent of the total starch in 30 minutes ; in about 12 per 

 cent of the grains and 30 per cent of the total starch in 

 45 minutes; in about 20 per cent of the grains and 36 

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

 D 548.) 



The reaction with sulphuric acid begins immediately. 

 Complete gelatinization occurs in about 90 per cent of 

 the entire number of grains and 98 per cent of the total 

 starch in 5 minutes; in more than 99 per cent of the 

 grains and total starch in 10 minutes. (Chart D 549.) 



The reaction with hydrochloric acid begins imme- 

 diately. Complete gelatinization occurs in about 8 per 

 cent of the entire number of grains and 16 per cent of the 

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

 grains' and 33 per cent of the total starch in 15 minutes; 

 in about 41 per cent of the grains and 55 per cent of the 

 total starch in 30 minutes; in about 55 per cent of the 

 grains and 70 per cent of the total starch in 45 minutes ; 

 in about 66 per cent of the grains and 80 per cent of the 

 total starch in 60 minutes. (Chart D 550.) 



The hilum becomes moderately distinct, but less so 

 than in R. albo-maculata. The lamella? are not visible. 

 Gelatinization begins -at the hilum and the process is 

 very similar to that in R. albo-maculata, except that the 

 stria? and granules formed after the beginning of gela- 

 tinization are not so large nor so distinct, and the margin 

 is less invaded by cracks, and hence fewer of the grains 

 are dissolved than in that starch. The completely gela- 

 tinized grains are the same in appearance as R. albo- 

 maculata. They are large, distorted, and do not retain 

 much of the form of the untreated grain. 



The reaction with potassium hydroxide begins im- 

 mediately. Complete gelatinization occurs in about 3 

 per cent of the entire number of grains and 8 per cent 

 of the total starch in 5 minutes ; in about 4 per cent of the 

 entire number of grains and 13 per cent of the total 

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

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

 6 per cent of the grains and 17 per cent of the total 

 starch in 45 minutes ; in about 14 per cent of the grains 

 and 23 per cent of the total starch in 60 minutes. (Chart 

 D551.) 



The hilum becomes as distinct as in R. albo-maculata, 

 but in only some of the grains are 2 canals seen to extend 

 from the hilum to the distal corners of the pressure 

 facets. The lamella? are not visible at any stage of the 

 reaction. Gelatinization begins at the hilum and in some 

 grains also at the distal corners of the pressure facets. 

 The progress of gelatinization is very similar to that in 

 R. albo-maculata, except that at no time in the reaction 

 is there evidence of lamellar structure, and the stria? 

 radiating from the hilum to the margin are not so dis- 

 tinct, but the granules in the gelatinized interior are 

 larger and more distinct. The gelatinized grains are 

 moderately large and somewhat distorted, but retain 

 more of the form of the untreated grain than those of 

 R. albo-maculata. 



The reaction with sodium salicylate begins imme- 

 diately. Complete gelatinization occurs in about 80 per 

 cent of the entire number of grains and 91 per cent of the 

 total starch in 3 minutes; in about 96 per cent of the 

 grains and 99 per cent of the total starch in 5 minutes ; 

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

 starch in 10 minutes. (Chart D 552.) 



The hilum is more distinct than in R. albo-macidata, 

 and a bubble is often formed there. The lamella? are not 

 visible. Gelatinization begins at the hilum in more 

 grains than in R. albo-maculata, and in the rest at the 

 distal corners of the pressure facets as in R. albo-macu- 

 lata. The methods of gelatinization do not differ from 

 those described under R. albo-maculata. The gelatinized 

 grains are large and considerably distorted, more so than 

 in R. albo-maculata. 



RlCHARDIA MRS. ROOSEVELT (HYBRID). 



(Charts D 545 to D 552.) 



Histologic Properties. 



In form the grains are simple and usually occur as 



separated components of aggregates, with the exception of 



a few which appear in disintegrating aggregates and in 



quite rare permanently isolated grains. No complete 



doublets, as noted for R. albo-maculata but not in R. 



clliottiana, were observed. The permanently isolated 



grains are fewer in number than in either parent. Pres- 



