RICHARDIA. 



125 



The following is a summary of the reaction-intensi- 

 ties of the hybrid as regards sameness, intermediateuess, 

 excess, and deficit in relation to the parents : 



40. COMPARISONS OF THE STARCHES OF RICHARDIA 

 ALBO-MACULATA, R. ELLIOTTIANA, AND R. MRS. 

 ROOSEVELT. 



In the histologic characteristics, polariscopic figures, 

 reactions with selenite, reactions with iodine and quali- 

 tative reactions with the various chemical reagents the 

 starches of the parents while exhibiting certain proper- 

 ties in common also show certain minor peculiarities by 

 which collectively they may be distinguished. The 

 starch of Richardia elliottiana in comparison with that 

 of R. albo-maculata is found to differ very little, chiefly in 

 the proportions of different kinds of grains. The hilum 

 is more often fissured, more frequently visible, and shows 

 more often a tendency to eccentricity. The lamellse are 

 more numerous. The size on the whole tends to be 

 slightly less. The polariscopic, selenite, and qualitative 

 iodine reactions exhibit many slight differences. In the 

 qualitative reactions with chloral hydrate, chromic acid, 

 hydrochloric acid, potassium hydroxide, and sodium sali- 

 cylate there are a number of points of differentiation, 

 mostly apparently of a very minor character. The starch 

 of the hybrid is in form, character of the hilium, lamella;, 

 size, polariscopic and selenite reactions, iodine reac- 

 tions and qualitative chemical reactions slightly closer 

 to R. albo-maculata than to the other parent, but such 

 differences as are observed are it seems of a decidedly 

 minor character. These starches are not well adapted 

 for differential study not only because of their very close 

 similarities in their properties, but also because of their 

 small size and the differences in gelatinizability of the 

 inner and outer parts, the former gelatinizing with com- 

 parative rapidity and the latter with comparative diffi- 

 culty, excepting in the rapid reactions. On this account 

 only few reactions were studied. 



Rea-ction-intensitifs Expressed by Light, Color, and Tempera- 

 ture Reactions. 

 Polarization: 



R. albo-maculata, moderate to high, value 70. 



R. elliottiana, moderate to high, lower than R. albo-maculata, 

 value 65. 



R. mrs. roosevelt, moderate to high, between the parents, value 67. 

 Iodine : 



R. albo-maculata, moderate, value 45. 



R. elliottiana, moderate, less than R. albo-maculata, value 40. 



R. mrs. roosevelt, moderate, the same as R. albo-maculata, value 45. 

 Gentian violet: 



R. albo-maculata, light, value 30. 



R. elliottiana, light, slightly deeper than in R. albo-maculata, 

 value 33. 



R. mrs. roosevelt, light, deeper than in either parent, value 35. 



Saf ranin : 



R. albo-maculata, light, value 33. 



R. elliottiana, light, slightly deeper than in R. albo-maculata, 



value 35. 

 R. mrs. roosevelt, light, light to moderate, deeper than in the 



parents, value 38. 

 Temperature : 



R. albo-maculata, majority at 75 to 76, all at 77 to 78.5, mean 



77.7. 

 R. albo-maculata, majority at 75 to 76, all at 77 to 78.5, mean 



77.7. 



R. elliottiana, majority at 74 to 75, all at 76 to 77, mean 76.5. 

 R. mrs. roosevelt, majority at 74 to 76, all at 76 to 78, mean 77. 



The reactivities of R. albo-maculata are higher than 

 those of the other parent in the polarization and iodine 

 reactions, and lower in the gentian violet, safranin, and 

 temperature reactions. The hybrid in the polarization 

 and temperature reactions is intermediate in value ; in 

 the iodine reaction it is the same as in R. albo-maculata 

 and higher than in R. elliottiana; and in the gentian- 

 violet and safranin reactions the figures are closer to, but 

 in excess of, those of R. elliottiana, and beyond the 

 parental extremes. 



Table 40 shows the reaction-intensities in percent- 

 ages of total starch gelatinized at definite intervals 

 (minutes) : 



TABLE A 40. 



VELOCITY-REACTION CURVES. 



This section treats of the velocity-reaction curves of 

 the starches of Ricliardia albo-maculata, R. elliottiana, 

 and R. mrs. roosevelt. (Charts D 545 to D 552.) 



There are very few points of interest in the accom- 

 panying eight charts. The starches are so nearly alike 

 that but little differences are shown in any of the charts. 

 In the reactions with chloral hydrate, sulphuric acid, and 

 sodium salicylate gelatinization occurs so rapidly that 



