BEGONIA. 



123 



higher reactivity of the seed parent, which in turn tends 

 to affect in the same direction the reactivities of the 

 hybrid. 



REACTION-INTENSITIES OF THE HYBRID. 



This section treats of the reaction-intensities of the 

 hybrid as regards sameness, intcrmediateness, excess, 

 and deficit in relation to the parents. (Table A 38 and 

 Charts .L) 533 to D 538.) 



The reactivities of the hybrid are the same as those 

 of the seed parent in the nitric-acid reaction ; the same 

 as those of the pollen parent in the polarization reaction ; 

 the same as those of both parents in none ; intermediate 

 in the reactions with temperature, chromic acid, pyrogal- 

 lic acid, and strontium nitrate, in all of which being 

 closer to those of the seed parent; highest with iodine, 

 gentian violet, safraniu, and chloral hydrate (in three 

 being closer to those of the pollen parent and in one 

 closer to that of the seed parent) ; and lowest in none. 



The following is a summary of the reaction-intensi- 

 ties : Same as the seed parent, 1 ; same as the pollen 

 parent, 1 ; same as both parents, ; intermediate, 4 ; high- 

 est, 4; lowest, 0. 



In these reactions the reactivities of the hybrid bear 

 only a somewhat closer relationship to the seed parent, 

 and there is a marked inclination to intermediateness 

 and highest reactivity. 



COMPOSITE CURVES OF THE REACTION-INTENSITIES. 



This section treats of the composite curves of the 

 reaction-intensities showing the differentiation of the 

 starches of Begonia, double white, B. socotrana, and B. 

 Julius. ( Chart E 38.) 



The most conspicuous features of this chart are : The 

 generally close correspondence in the courses of all three 

 curves, although in three instances the curves are well 

 separated. The lower position of the curve of B. double 

 white in relation to that of the other parent in the 

 reactions with polarization, iodine, gentian violet, and 

 safranin ; the higher position with temperature, chloral 

 hydrate, chromic acid, pyrogallic acid, and strontium 

 nitrate; and the same position with nitric acid. The 

 varying relationship of the hybrid curve to the parental 

 curves. It is the same as the curve of B. socotrana in 

 the reaction with polarization ; the same as that of 

 B. double white with chloral hydrate and strontium 

 nitrate; the same as both parents with nitric acid; the 

 highest in the three with iodine, gentian violet, and 

 safranin ; and intermediate with temperature, chromic 

 acid, and pyrogallic acid. 



39. COMPARISONS OF THE STARCHES OF BEGONIA 

 DOUBLE DEEP ROSE, B. SOCOTRANA, AND B. 



SUCCESS. 



In the histologic characteristics, polariscopic figures, 

 reactions with selenite, reactions with iodine, and quali- 

 tative reactions with various reagents all three starches 

 have properties in common in varying degrees of de- 

 velopment, the sum of which in each case is distinctive. 

 The starch of Begonia socotrana in comparison with 

 that of B. double deep rose shows an absence of com- 

 pound grains and aggregates; the grains are more regu- 

 lar, but such irregularities as occur are more obvious 

 and striking ; the grains are more elongated ; and round 



and nearly round forms are very rare. The hiluni is 

 somewhat less rarely fissured ; there is an individual form 

 of fissuring; and there is more eccentricity. The laniulloe 

 are finer and less distinct; several are present that are 

 not seen in B. double deep rose; and they are much more 

 numerous. The size is larger. The reactions with polari- 

 zation, selenite, and iodine exhibit many differences. In 

 the qualitative reactions with chloral hydrate, chromic 

 acid, pyrogallic acid, nitric acid, and strontium nitrate 

 the differences are numerous and some of them are quite 

 striking and distinctly individualize the starch. The 

 starch of the hybrid in comparison with the starches 

 of the parents shows a closer relationship to the starch 

 of B. double deep rose in the characters of the irregu- 

 larities of the grains and in the characters of the hilum ; 

 more like the other parent in the form of the grains, 

 eccentricity of the hilum, character and arrangement and 

 number of the lamella, and size of the grains. It has, 

 however, less irregularities in the grains than in either 

 parent. It is nearer B. socotrana in the polarization 

 figures and appearances with selenite, and nearer also in 

 the iodine reactions. It shows peculiarities of both pa- 

 rents in the quantitative reactions with chloral hydrate, 

 chromic acid, pyrogallic acid, nitric acid, and strontium 

 nitrate, but is closer to B. double deep rose. 



Reaction-intensities Expressed by Light, Color, and Tempera- 

 ture Reactions. 

 Polarization : 



B. double deep rose, moderately low to high, value 50. 



B. socotrana, moderate to high, higher than in B. double deep rose, 



value 60. 



B. success, moderate to high, the same as in N. socotrana, value CO. 

 Iodine : 



B. double deep rose, moderate, value 45. 



B. socotrana, light to moderate, much lighter than in B. double 



deep rose, value 30. 



B. success, light to moderate, the same as in B. socotrana, value 30. 

 Gentian violet: 



B. double deep rose, light to moderate, value 40. 



B. socotrana, light to moderate, less than in B. double deep rose, 



value 35. 



B. success, light to moderate, the same as in B. socotrana, value 35. 

 Safranin : 



B. double deep rose, moderate to deep, value 60. 



B. socotrana, moderate, less than in B. double deep rose, value 55. 



B. success, moderate to deep, the same as in B. double deep rose, 



value 60. 

 Temperature: 



B. double deep rose, in majority at 64 to 65.5, in all at 67 to 68.8, 



mean 67.8. 

 B. socotrana, in majority at 79 to 80, in all at 81 to 81.8, mean 



81.4. 

 B. success, in majority at 62 to 64, in all at 68 to 69, mean 68.5. 



The reactivity of B. double deep rose is lower than 

 that of the other parent in the polarization reaction; and 

 higher in those with iodine, gentian violet, safranin, and 

 temperature. The reactivity of the hybrid is the same 

 or practically the same as that of B. double deep rose 

 in the reaction with safranin; the same or practically 

 the same as those of B. socotrana with polarization, iodine, 

 and gentian violet; and intermediate between those of the 

 parents in that with temperature. The hybrid is closer 

 to B. double deep rose than to B. socotrana in the safranin 

 and temperature reactions, and the reverse in those with 

 polarization, iodine, and safranin. 



Table A 39 shows the reaction-intensities in percent- 

 ages of total starch gelatinized at definite intervals (sec- 

 onds and minutes) : 



