762 



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



tinized grains are much swollen and distorted, so that 

 they do not resemble the form of the untreated grain. 



The reaction with potassium sulphide is instanta- 

 neous j no details of the reaction can be determined. The 

 gelatinized grains are much swollen and distorted, so 

 that they do not resemble the untreated grain. 



The reaction with sodium hydroxide begins imme- 

 diately; all the grains are gelatinized in 10 seconds. The 

 reaction is so rapid that the minute steps can not be 

 studied. The gelatinized grains are much swollen and 

 distorted so that they usually do not resemble the form 

 of the untreated grains. 



The reaction with sodium sulphide begins immedi- 

 ately; many are gelatinized in 5 seconds; all in 10 

 seconds. The reaction is so very rapid that the minute 

 steps of the process can not he determined. The gela- 

 tinized grains are swollen and much distorted so that 

 they do not resemble the form of the untreated grain. 



The reaction with sodium salicylate begins immedi- 

 ately. Complete gelatinization occurs in about 88 per 

 cent of the entire number of grains and 89 per cent of 

 the total starch in 1 minute; in about 98 per cent of 

 the grains and 99 per cent of the total starch in 2 

 minutes. 



The hilum is very distinct and a bubble is usually 

 formed there. The lamellae are at first distinct, but later 

 become obscured. A narrow, refractive band is formed, 

 quickly, about the margin of the grains before gelatiniza- 

 tion begins and remains there as gelatinization proceeds. 

 Gelatinization begins at the distal margin, and is pre- 

 ceded by a pitted appearance of the starch at the distal 

 end. From here it proceeds rapidly and smoothly toward 

 the proximal end until the hilum is reached. There the 

 bubble enlarges, then shrinks and disappears, and the 

 hilum in enlarging splits the remaining ungelatinized 

 material at the proximal end into 2 or 3 pieces which 

 rapidly gelatinize. The last to gelatinize are the pieces 

 at the sides. The gelatinized grains are large and much 

 distorted at the distal end but not at the proximal end, 

 and so they retain some of the form of the untreated 

 grain. 



The reaction with calcium nitrate begins imme- 

 diately. Complete gelatinization occurs in all but rare 

 grains in 15 seconds and in 100 per cent of both the grains 

 and total starch in 30 seconds. 



The reaction with uranium nitrate begins imme- 

 diately. Complete gelatinization occurs in about 80 per 

 cent of the entire number of grains and 96 per cent of 

 the total starch in 30 seconds; in 100 per cent of both 

 the grains and total starch in 1 minute. 



The reaction with strontium nitrate begins imme- 

 diately. Complete gelatinization occurs in all but a few 

 grains in 15 seconds, all in 30 seconds. 



The reaction with cobalt nitrate begins immediately. 

 Complete gelatinization occurs in over 99 per cent of 

 both the grains and total starch in 45 seconds, and in 

 100 per cent of both the grains and total starch in 2 

 minutes. 



The reaction with copper nitrate begins immedi- 

 atly. Complete gelatinization occurs in nearly all the 

 grains in 15 seconds, and in all grains (100 per cent of 

 both the grains and total starch) in 30 seconds. 



The reaction with cupric chloride begins immedi- 

 ately. Complete gelatinization occurs in about 95 per 



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

 total starch in 30 seconds; and in all but rare smaller 

 grains and parts of the grains and margin of larger 

 grains are gelatinized — over 99 per cent of both the 

 grains and total starch in 1 minute. 



The reaction with barium chloride begins immedi- 

 ately. Complete gelatinization occurs in about 85 per 

 cent of the entire number of grains and 97 per cent of 

 the total starch in 5 minutes ; in about 93 per cent of the 

 grains and 99 per cent of the total starch in 15 minutes ; 

 in about 95 per cent of the grains and 99 per cent of the 

 total starch in 30 minutes; in about 97 per cent of the 

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

 in about 98 per cent of the grains and over 99 per cent 

 of the total starch in 60 minutes. (Chart D 618.) 



The hilum becomes distinct, and the lamella? are visi- 

 ble but not distinct. Gelatinization begins at the hilum, 

 which enlarges somewhat, and large branching fissures 

 extend from the hilum to the distal end, or to the margin, 

 if the distal end can not be determined on account of the 

 centric position of the hilum, and these widen as the 

 hilum swells, and divide much of the grain into coarse 

 granules which are soon gelatinized, the rest of the grain 

 is pushed to the margin and these form a lamellated 

 unstriated band which becomes thinner and more and 

 more nearly transparent until only the capsule remains. 



The gelatinized grains are large and thin-walled and 

 somewhat distorted, but show some of the form of the 

 untreated grain. 



The reaction with mercuric chloride begins imme- 

 diately. Complete gelatinization occurs in about 98 per 

 cent of the entire number of grains and over 99 per cent 

 of the total starch in 1 minute ; complete gelatinization 

 in all but very rare grains in 1 minute and 30 seconds; 

 and in all grains in 2 minutes. 



The hilum becomes distinct, and the lamellae are at 

 first not distinct, but later become moderately distinct. 

 Gelatinization begins at the hilum, which enlarges, and 

 the starch immediately surrounding the hilum, in the 

 meantime, is divided into coarse granules by irregular 

 fissures proceeding from the hilum. As the hilum en- 

 larges, the grain enlarges also, and the more resistant 

 starch is pushed to the margin where it forms a lamel- 

 lated finely striated band, around the inner border of 

 which are the granules whose formation has been de- 

 scribed. This marginal band becomes gradually thinner 

 and more nearly transparent as the grain increases in 

 size until finally the thin capsule only is left, and the 

 granules gelatinize somewhat more slowly but finally also 

 disappear. The gelatinized grains are large and some- 

 what distorted, but retain some resemblance to the form 

 of the untreated grain. 



Cymbididm eburneum (Pollen Parent). 



(Plate 24, fig. 143; Charts D 616 to D 618.) 

 Histologic Properties. 

 In form, the grains are usually simple and isolated, 

 with the exception of a moderately small number which 

 appear in aggregates of from 2 to 10 components. Com- 

 pound grains of 2 components are rarely observed. The 

 majority of isolated grains are the separated components 

 of aggregates, and are somewhat greater in number than 

 in C. lowianum. A moderately large proportion of the 

 grains of the isolated disaggregate type are present, but 



