IIUS. 



1(17 



same as that of the other parent in the safranin reaction ; 

 and the highest of the three in the temperature reaction. 

 The hybrid is nearer /. iberica than to /. cengialti in the 

 polarization, iodine, and temperature reactions, hut 

 nearer the other parent in the gentian violet and safranin 

 reactions. 



Table A 31 shows the reaction-intensities in percent- 

 ages of total starch gelatinized at definite intervals 

 (minutes). 



Velocity-reaction Curves. 



This section treats of the velocity-reaction curves of 

 the starches of Iris iberica, I. cengialti, and /. dorak, 

 showing the quantitative differences in the behavior 

 toward different reagents at definite time-intervals. 

 (Charts I) 100 to D420.) 



The most conspicuous features of this group of curves 

 are: 



(1) The closeness of all three curves, occasionally 

 almost identical, indicating corresponding relationships 

 of the parents and little modification of parental pecu- 

 liarities in the hybrid. The hybrid curve relative to the 

 parental curves shows marked variability in so far as it 

 sometimes follows one or the other parent closely, or is 

 the highest or the lowest or tends to intermediateness, 

 as the case may be. The hybrid curve inclines to differ 

 as much from the parental curves as the latter do from 

 each other. The tendency to separation of the parental 

 curves is more marked in this group than in the pre\ tous 

 group, and with the exception of the reactions with sul- 

 phuric acid, potassium sulphocyanate, potassium sul- 

 phide, sodium hydroxide, sodium salicylate, strontium 

 nitrate, cobalt nitrate, copper nitrate, and barium chlo- 

 ride there is more or less marked separation, with a 

 tendency generally for two of the three curves to keep 

 close, sometimes the two parental curves and at others 

 one parental curve with the hybrid curve. In some of 

 the reactions noted there is definite although unimportant 

 separation, as in those with sodium salicylate, strontium 

 nitrate, copper nitrate, and barium chloride. 



(2) The sameness or marked closeness of the pa- 

 rental curves in the reactions with chloral hydrate and 

 chromic acid ; the sameness or marked closeness of all 

 three curves with sulphuric acid, potassium sulphocya- 

 nate, potassium sulphide, sodium hydroxide, sodium sali- 

 cylate, strontium nitrate, cobalt nitrate, and copper 

 nitrate; the sameness or marked closeness of the hybrid 

 curve with one or the other parental curve with pyro- 

 gallic acid, nitric acid, hydrochloric acid, calcium ni- 

 trate, and mercuric chloride. 



(3) The varying positions of the hybrid curves in 

 relation to the parental curves in the different reactions, 

 and the marked tendency for the hybrid curves to be 

 higher or lower than the parental curves with almost not 

 the least tendency to intermediateness. 



(4) In a few instances there is evidence of a com- 

 paratively marked early resistance of one or two or all 

 three starches, as the case may he, as in /. iberica in the 

 chloral-hydrate and 7. iberica and /. cengialti in the 

 chromic-acid reactions; in /. cengialti in those with pyro- 

 gallic acid, nitric acid, sodium sulphide, copper nitrate, 

 and cupric chloride. This peculiarity, in so far as the 

 parents are concerned, is therefore almost confined to 

 /. cengialti, and it is not observed in the hybrid unless 

 perhaps in the uranium nitrate reaction. 



(5) The earliest period during the CO minutes at 

 which the three curves are best separated to differentiate 

 tlie starches varies with the different reagents. Approxi- 

 mately, this period occurs within 5 minutes in most of 

 the reactions, including the reactions with pyrogallic 

 acid, nitric acid, sulphuric acid, potassium hydroxide, 



pota -iuui sulphocyanate, sodium hydroxide, sodium sul- 

 phide, sodium salicylate, calcium nitrate, uraniun 

 tiiii'-, ami copper nitrate; at the end of L5 minutefi with 

 chloral hydrate, chromic acid, hydrochlorii acid, potas- 

 sium mde: , Hum nitrate, and cupric chl 



and at the end of 60 In Hi lit.- with p iulphide, 



cobalt nitrate, barium chloride, chloride. 



In some of these cases there i- little or no practical dif- 

 ferentiation at tie ..Is. 



REA( I ION-IN1 BNSITIES 01 Till'. 1 1 ', BHID. 



This section treat- of the reaction intensities of the 

 hybrid as regards sail titermediatem . and 



deficit in relation to the parents. (Table A 3 1 



Charts I) 100 to l» 120.) 



The reactivities of the hybrid are the same as those 

 of the seed parent in the reactions with polarization, 

 iodine, sodium hydroxide, barium chloride, and mercuric 



chloride; the same as those of the pollen parent in those 

 with safranin, hydrochloric acid, and potassium sulphide; 

 the same as those of both parents in the cobalt-nitrate 

 reaction; intermediate in that with calcium nitrate, and 

 closer to the seed parent; highest in those with gentian 

 violet, temperature, chromic acid, pyrogallic acid, n 

 acid, sulphuric acid, potassium iodide, sodium sulphide, 

 uranium nitrate, strontium nitrate, copper nitrate, and 

 cupric chloride (in six being closer to the seed parent, 

 in five closer to the pollen parent, and in one as close 

 to one as to the other parent) ; and lowest with chloral 

 hydrate, potassium hydroxide, potassium sulphocyanate, 

 ami sodium salicylate (in one being closer to the 

 parent, in two closer to the pollen parent, and in one as 

 close to one as to the other parent) . 



The following is a summary of the reaction-intensi- 

 ties: Same as seed parent, 5; same as pollen parent, 3; 

 same as both parents, 2; intermediate, 1; highest, 11 ; 

 lowest, 4. 



The seed parent has apparently influenced to a more 

 marked extent than the pollen parent the properti - of 

 the starch of the hybrid. The sameness to the 

 parent coupled with the tendency to closeness to the seed 

 parent in the reactions in which the hybrid is in . \ ess 

 of the parents is quite marked. The tendency to the 

 highest or lowest reactivity of the hybrid is quite conspic- 

 uous this being noted in more than half of the reactions. 



Composite Curves of Reaction-intensities. 



This section treats of the composite curves of the 

 reaction-intensities, showing the differentiation of the 

 starches of Iris iberica, I. cengialti, and /. dorak. (Chart 

 E31.) 



The most conspicuous features of this chart are: 



(1) The marked closeness of all three curves through- 

 out, there being no tendency in any reaction for a marked 

 departure of any one curve from the other two. The 

 curves are so close as to suggest either very closely re 

 lated species or mere varieties, tin- latter rather than the 

 former. The species are, however, classed in dill' 

 subgenera: 7. iherica in Oncocyclus, and 7. cengialti in 

 Pogoniris and Regelia. I. cengialti is regarded as ; 

 probably a dwarf variety of /. pallida, which it closely 

 resembles. For the most pan the differences in the curves 

 fall within or close to the limits id' error of experiment, 

 so that little or nothing of importance ran be gained 

 from a critical comparison. At some points one parental 

 curve is higher than the other; and the hybrid curve 

 courses with one or the other or both parental en 

 here and there running above or below both. 



(2) In 7. iberica, the very high reactions with sul- 

 phuric acid, potassium sulphocyanate, and sodium sali- 

 cylate; the high reactions with chromic acid and sodium 



