720 



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



the differences between the percentages of grains gela- 

 tinized and of the total starch become lessened. 



The reaction with pyrogallic acid begins in a few 

 grains immediately. Complete gelatinization occurs in 

 about 3 per cent of the entire number of grains and 4 

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

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

 minutes ; in about 4 per cent of the grains and 9 per cent 

 of the total starch in 30 minutes ; in about 5 per cent 

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

 minutes; in about 6 per cent of the grains and 11 per 

 cent of the total starch in 60 minutes. (Chart D 547.) 



The reaction with nitric acid begins immediately in 

 a few grains. Complete gelatinization occurs in about 4 

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

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

 of the grains and 22 per cent of the total starch in 15 

 minutes; in about 18 per cent of the grains and 28 per 

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

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

 45 minutes; in about 36 per cent of the grains and 48 

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

 D548.) 



The reaction with sulphuric acid begins immediately. 

 Complete gelatinization occurs in about 87 per cent of 

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

 starch in 5 minutes; in about 98 per cent of the grains 

 and in more than 99 per cent of the total starch in 10 

 minutes. (Chart D 549.) 



The reaction with hydrochloric acid begins imme- 

 diately. Complete gelatinization occurs in about 9 per 

 cent of the entire number of grains and 18 per cent 

 of the total starch in 5 minutes ; in about 25 per cent of 

 the grains and 35 per cent of the total starch in 15 min- 

 utes; in about 43 per cent of the grains and 62 per cent 

 of the total starch in 30 minutes; in about 50 per cent 

 of the grains and 75 per cent of the total starch in 45 

 minutes; in about 56 per cent of the grains and 82 per 

 cent of the total starch in 60 minutes. (Chart D 550.) 



The hilum becomes moderately distinct, and the la- 

 mella? are not visible. Gelatinization begins at the hilum, 

 and as the hilum grows larger stria? radiate in all direc- 

 tions from it to the margin, and the starch thus sepa- 

 rated becomes granular as gelatinization proceeds; iu 

 the meantime several deep cracks appear in the margin 

 of the grain, the capsule is evidently dissolved at these 

 points, and granules separate off from the ungelatinized 

 starch, float off, and are dissolved. The few grains which 

 are completely gelatinized before dissolution are large 

 and distorted and do not retain much of the form of the 

 untreated grain. 



The reaction with potassium hydroxide begins imme- 

 diately. 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 2 per cent of the 

 grains and 8 per cent of the total starch in 15 minutes; 

 in about 3 per cent of the grains and 10 per cent of the 

 total starch in 30 minutes; in about 5 per cent of the 

 grains and 13 per cent of the total starch in 45 minutes; 

 in about 13 per cent of the grains and 21 per cent of the 

 total starch in 60 minutes. (Chart D 551.) 



The hilum becomes moderately distinct, and in some 

 grains 2 canals or fissures are seen to extend from the 

 hilum to the distal corners of the pressure facets, and 



these enlarge as the hilum enlarges. The lamellae are not 

 visible until gelatinization is far advanced. Gelatiniza- 

 tion begins at the hilum, which begins to enlarge, and at 

 the same time the substance of the grain is divided into 

 long spicules by fine striae radiating from the hilum to 

 the margin. As the hilum and the grain continue to 

 enlarge the more resistant starch is pushed to the margin, 

 and there forms a lamellated band which is divided into 

 small granules by the striae mentioned, which stria? have 

 been spread apart during the swelling of the grain. The 

 starch in the interior of the grain, in the meantime, has 

 become granular, and remains so until the marginal 

 starch is completely gelatinized. The gelatinized grains 

 are moderately large and somewhat distorted, but show 

 some of the form of the untreated grain. 



The reaction with sodium salicylate begins imme- 

 diately. Complete gelatinization occurs in about 85 per 

 cent of the entire number of grains, and 92 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 becomes moderately distinct, and a bubble 

 is often formed there before gelatinization begins. Ex- 

 tending from the hilum to the distal pressure-facet cor- 

 ners in many grains are 2 lines or canals. The lamellae 

 are not seen. Gelatinization begins in the less resistant 

 grains at the hilum and in the more resistant at the 

 distal corners of the pressure facets ; in the first named, 

 the grain becomes nearly transparent and the hilum 

 swells, and the bubble if present swells, shrinks, and then 

 disappears, at first pushing the ungelatinized starch to 

 the margin, where it is soon gelatinized. During this 

 process the intracapsular and capsular parts swell some- 

 what unevenly and become very large, with many long 

 folds in the capsule. In the second-named grains, the 

 marginal starch at the pressure-facet angles gelatinizes 

 and the grain broadens transversely, as the hilum and the 

 lines connecting it with the pressure-facet angles swell 

 somewhat; and the bubble if present, swells, shrinks, and 

 disappears. The ungelatinized portion of the starch is 

 by this method divided into two portions, proximal and 

 a distal, of which the distal starch gelatinizes first. The 

 gelatinized grains are moderately large and somewhat 

 distorted, some retain somewhat of the form of the un- 

 treated grain and others do not. 



RlCHARDIA ELLIOTTIANA (POLLEN PARENT ). 

 (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 

 as permanently isolated grains. No complete doublets 

 were observed, and the permanently isolated grains are 

 fewer in number than in R. albo-maculata. Pressure 

 facets are present on most grains, as in R. albo-maculata. 

 The grains are usually regular in form, and the same 

 forms of irregularities may occur, as in R. albo-maculata. 

 Rounded and ellipsoidal grains with identations at indefi- 

 nite points are more numerous than in the latter species. 

 The conspicuous forms of the separated components are 

 polygonal, high dome-shaped with a plane or concave 

 distal end, low dome-shaped with a plane or pointed dis- 



