168 Scientific Proceedings, Royal Dublin Societr. 



SUMMAKY. 



1. Prolonged darkness has no decided effect upon the distribution of th& 

 indirect oxydase (peroxidase) reactions or of the inhibitor in the leaf of Iris 

 germanica. 



2. The distribution of oxydase and inhibitor, in the flowers of a number 

 of varieties of Iris, lias been examined and correlated with the natural 

 colouring of the flowers. Among these it is probable that both dominant and 

 recessive whites and yellows will be found to occur, judging from the chemical 

 reactions, an inliibitor being present in the dominants. Related varieties have 

 very similar oxydase contents. On the whole, the behaviour of Iris flowers 

 follows closely that of other species investigated by Keeble, Arnrstrong, and 

 Jones. 



I wi.<h to record my indebtedness to Prof. H. H. Dixon for his continued 

 interest in this work and his helpful criticism. 



Bibliography. 



1. Atkins, W. R. G-. — Oxydases and their Inhibitors in Plant Tissue.=. Sei. 



Proc. R. Dubl. Soc. Vol. xiv (N.S.), 1913, p. 144; and Notes, Bot. 

 School, Trin. Coll., Dubl., vol. ii, No. 4, 1913, p. 185. 



2. Clarke, E. D.— Torreya, vol. xi, Nos. 2-5, 1911. 



3. Dykes, W. R.— The Genus Iris. Cambr. Univ. Press, 1913. 



4. Keebi.e, F., and Armstrong, E. F. — The Formation of Anthocyau 



Pigments in Plants [General Title], Proc. Roy. Soc, Ser. B, vol. Ixxxv, 

 1912, p. 214. 



5. Part, ii, loc. cil.,]^. 460. Part, iii, Journ. Genetics, vol. ii, No. 3, 



1912, p. 277. 



6. Keebi.k, F., Armstrong, E. F., and Jones, W. N. Part iv, Proc. Eoy. 



Soc, Se B, vol. Ixxxvi, 1913, p. 308. [See foot-note to this paper.] 



7. Jones, W. N., Part v, he. clt., p. 318. 



8. Part vi, loc. cif., vol. Ixxxvii, 1913, p. 113. 



9, Lynch, R. J.— The Book of the Iris. J. Lane : Loudon, 1904. 



