KH-IIAKDIA. 



125 



|n. '.. Mi-MMsoss or THB STARCHES OK Ki< IIARDIA 



A I !.-> -MAI I I Al \, K. KL1.10TT1AKA, AND R MB8. 

 BO08KVKLT. 



Iii the histologic characteristics, polariscopic figures, 

 urns with selenite, reactions with iodine and quali- 

 reactions with the various chemical reagents the 

 Marches of the parents while exhibiting certain proper- 

 n inmn aim show certain minor |H>ciiliarities by 

 whirh collectively they may be distinguished. The 

 -iiir.'h .'f l:\'-iiiiril\n elliottiana in comparison with that 

 of /.'. albo-macvltita is found to differ very little, chiefly in 

 the pro|xirtions of different kinds of grains. The hilum 

 re often fissured, more frequently visible, and shows 

 more often n ; to eccentricity. The lamella? are 



numerous. The size on the whole tends to be 

 -lightly leas. The polariscopic, selenite, and qualitative 

 !:]!. p .'. t;"iis exhibit many slight differences. In the 

 qualitative reactions with chloral hydrate, chromic acid, 

 hy<lr< hloric acid, potassium hydroxide, and sodium sali- 

 cylatc there are a number of points of differentiation, 

 ' v apparently of a very minor character. The starch 

 of the hybrid is in form, character of the hilium, lamellae, 

 polariscopic and selenite reactions, iodine reac- 

 and qualitative chemical reactions slightly closer 

 albn-macul'ita 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. 



Jtfuction-intntitirt Krfmtfd by lAgkt, Color, mint Trmpm- 

 turr Reaction*. 



P'llarUation: 



K lt->-ni<-nlta. moderate to hi(th. valur 70. 



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



value 05. 

 R. mra. rooeevrlt, moderate to high, between the parent*. Tain* 87. 



R. albo-maeulata. moderate, value 45. 



R. eiliottiaoa. moderate. lea* than R. albo-maeulata. value 40. 

 R. mr rooeevelt. moderate, the MOM a* R. albo-maeulata. value 45. 

 Gentian violet: 



R- albo-marulata, light, value 30. 



R. etliottiana. lifht. ilichtly deeper than in R. albo-maeulata. 



value 33. 

 R mn. roonvelt. light, deeper than in either parent, value 35. 



Bafraain: 



K. ll> niruli. light, value 33. 



R. elhutUana, lihl, Wichtly deeper than in R. albo-roarulata. 



value 35. 

 R. mn. RKMewlt. liht. light to moderate, deeper than to UM 



parenta, value 38. 

 Temperature: 



R. albo-marulata. majority at 75 to 76*. all at 77 to 78.5*. mean 



77.7*. 

 R. albo-maeulata. majority at 75 to 76*. all at 77 to 78.5'. mean 



77.7*. 



R. eUiottiana, majority at 74 to 75*. all at 70 to 77*. mean 70.6*. 

 R. mra. roonvelt. majority at 74 to 70*. all at 76 to 78*. mean 77*. 



The reactivities of K. albo-marulaio 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 polari/ 

 and tem|K'rature reactions is intermediate in value; in 

 the iodine reaction it is the same as in R. albo-macul<iln 

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

 violet and saf raiiin 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) : 



TABU A 40. 



VELOCITY-REACTION CURVES. 



This section treats of the velocity-reaction curves of 

 the starches of Riehardia albo-marulala, R. tUwltiana, 

 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 hut little differences are shown in any of the charts. 

 In the reactions with chloral hydrate, sulphuric acid, and 

 sodium sahcylate gelatinization occurs so rapidly that 



