IRIS. 



113 



(5) In /. sindjarensis the very high reactions with 

 pyrogallic acid, nitric acid, sulphuric acid, hydrochloric 

 acid, potassium hydroxide, potassium iodide, potassium 

 sulphocyanate, sodium hydroxide, sodium sulphide, and 

 cupric chloride; the high reactions with polarization, 

 chromic acid, sodium salicylate, calcium nitrate, uranium 

 nitrate, strontium nitrate, copper nitrate, and mercuric 

 chloride; the moderate reactions with iodine, gentian 

 violet, safranin, and temperature; the low reactions with 

 cobalt nitrate and barium chloride reactions ; and the very 

 low reactions with chloral hydrate and potassium 

 sulphide. 



(6) In the hybrid the very high reactions with pyro- 

 gallic acid, nitric acid, sulphuric acid, hydrochloric acid, 

 potassium hydroxide, potassium iodide, potassium sul- 

 phocyanate, sodium hydroxide, and sodium sulphide; the 

 high reactions with polarization, chromic acid, sodium 

 salicylate, calcium nitrate, uranium nitrate, strontium 

 nitrate, copper nitrate, cupric chloride, and mercuric 

 chloride; the moderate reactions with iodine, gentian 

 violet, safranin, and temperature ; and the very low reac- 

 tions with chloral hydrate, potassium sulphide, cobalt 

 nitrate, and barium chloride. 



Following is a summary of the reaction-intensities: 



NOTES ON THE IRISES. 



Among the very striking features of the four charts 

 are: 



The closeness of all three curves in each chart and 

 the wavering relationship of the hybrid curve to one 

 or the other or both parental curves, occasionally going 

 above or below parental extremes in Charts E 30, E 31, 

 and E 33, and frequently (15 out of 26 reactions) in 

 Chart E 32 ; the close correspondence of the curves of 

 the three sets of rhizomatous irids (Charts E 30, E 31, 

 and E32) ; and the very definite differentiation of the 

 curves of the rhizomatous and tuberous series. 



In the first set the cross is between members of the 

 subgenera Ococyclus and Apagon; in the second set, 

 between members of the subgenera Ococi/clns and Pogo- 

 niris and Regella; in the third set, between members of 

 the subgenus Pogoniri-s and Eegelia; and in the fourth 

 set, between members of the subgenus Juno. In the 

 three sets of rhizomatous irids the curves are so nearly 

 alike as to suggest that the subgeneric division of Has- 

 selliring referred to in Part II is botanically largely 

 artificial, and that the primary division into rhizomatous 

 and tuberous groups is well founded in expressing funda- 

 mental botanical differentiation. Although only one set 

 of tuberous irises was studied in detail in this research, 

 cursory investigations were made with other members of 

 this series (including /. histrio Eeichb., 7. tingitiana 

 Boiss and Kent., I. reticulata M. Bieb.. 7. alata Poi'r., and 

 7. caucasica Hoffm. ; the first three belonging to the sub- 

 genus Xiphion and the last two to the subgenus Juno), 

 in all of which the reactions were in close correspondence 

 with those of this set. In the previous research with 

 irid starches it was found that the members of the rhizo- 

 8 



matous series have in comparison with those of the tuber- 

 ous series, besides different histologic properties, a lower 

 degree of polarization, lower reactivities with iodine, 

 higher reactivities with gentian violet and safranin, and 

 distinctly higher temperatures of gelatinization. Owing 

 to improper strengths of the reagents, evidence was not 

 recorded that is satisfactory to differentiate the starches 

 then studied; but there was clear evidence of grouping 

 of the two series, the members of the rhizomatous series 

 having, as a whole, higher reactivities with chloral hy- 

 drate and chromic acid, and lower reactivities with ferric 

 chloride and Purdy's solution. These results are in 

 accord with those of the present research, there being in 

 the rhizomatous series mean lower reactivities with pola- 

 rization and iodine, higher reactivities with gentian 

 violet and safranin, higher temperature of gelatinization, 

 higher reactivity with chloral hydrate, the same or a 

 tendency to a higher reactivity with chromic acid, and a 

 lower reactivity with potassium hydroxide. 



The types of curves of the rhizomatous and tuberous 

 irids, respectively, differ chiefly in the relative lowness 

 of the rhizomatous curve in the reactions with pyrogallic 

 acid, nitric acid, hydrochloric acid, potassium hydroxide, 

 potassium iodide, sodium hydroxide, sodium sulphide, 

 calcium nitrate, uranium nitrate, copper nitrate, cupric 

 chloride, and mercuric chloride, and the highness in those 

 with chloral hydrate and sodium salicylate. Probably 

 among the irids will be found some species or hybrid that 

 will, as in case of the crinums, bridge the two series. 



Owing to the almost invariable closeness of the three 

 curves in each set, opportunity is rarely afforded for a 

 satisfactory study of the relationships of the hybrid to 

 one or the other or both parents. It will be seen by the 

 following summary, the figures of which are to be taken 

 as having only tentative values, that the different hy- 

 brids vary in their parental relationships, especially in 

 their intermediate, highest, and lowest records. 



The following is a summary of the reaction-intensi- 

 ties of the hybrids as regards sameness, intermediateness, 

 excess, and deficit in relation to the parents : 



The differences in the reactive-intensities of the rhi- 

 zomatous and tuberous series are indicated in the fol- 

 lowing table : 



