MENDELIAN CHARACTERS IN BEARDED IRISES. 289 



MENDELIAN CHARACTERS IN BEARDED IRISES. 



By A. J. Bliss, F.R.H.S. 



Some twelve years ago Mr. W. R. Dykes called my attention to a 

 character in Bearded Irises that I had hitherto taken no notice of — 

 the colouring of the base of the leaves in some varieties. Another 

 character, the brown tipping of the hairs of the beard, had always 

 interested me, and having at the time several large pods of fertile 

 seed of the Iris ' Maori King ' crossed by other varieties, I thought 

 it would be worth while to keep records of these characters for the 

 whole of these series of seedlings, in the hope that they might give, 

 at least, an indication whether they were Mendelian characters, and 

 whether, in each case, one or several factors were involved. As I 

 keep full records of all my seedlings, it would also be possible to see 

 if there was any connexion between these two characters and the 

 types and colours of the flowers. I may say at once that there 

 seems to be no evidence of any such connexion, nor of any connexion 

 between the characters themselves, as the analysis of distribution 

 in pairs given for G. 190 shows, and the analysis of the other crosses 

 show similar indeterminate results. The numbers are, however, too 

 few to justify any very definite conclusion. The figures for the 

 single characters, however, do tend to show that both the colouring 

 of the leaves and the tipping of the beards are Mendelian characters — 

 possibly single unit characters — but from observation of many other 

 seedlings of other crosses I am inclined to think that, at any rate 

 in the colouring of the leaves, two or more cumulative colour factors 

 (C.C.C.) are concerned, as well as a red factor (R.) and a blue factor (B.). 

 For the range of intensity of the colouring — from very faint and 

 confined to a few inches of the leaf at the base to a deep indigo suffusing 

 the leaves nearly to their tips — seems too great to be accounted for 

 by the difference of a single or double dose in heterozygote or homozy- 

 gote with only one unit character. The " red " and "blue " differences 

 are also quite distinct. 



The tipping of the beard also ranges from the presence of a few 

 brown-tipped hairs to a staining of the whole beard nearly down 

 to the roots of the hairs, and I should therefore expect cumulative 

 factors for this character also. 



Though based on the observation of large numbers of seedlings, 

 these are of course only impressions, and even the experiment of 

 these crosses and their results recorded here can make no claim to 

 scientific exactitude. For the crosses were not made originally for 

 this purpose, and the flowers were not protected. The degree of 

 reliance, however, in the results may be indicated by the fact that 



