PARNELL, RANGASWAMI AYYANGAR, AND RAMIAH 



89 



Six unpigmented F3 plants, from No. 6U-N of Table IX, were crossed 

 with pollen from a pure unpigmented strain of Garudan Samba. One cross 

 gave two plants one of which was pigmented whereas the other was not. In 

 the other five lots, comprising 13 plants, all were unpigmented. 



(/) Dark purple colouring of pulvinus and auricle. 



In this character a very dark purple colouring of the epidermis is present 

 in the pulvinus and also in the auricle and pulvinus-like region from which it 

 springs at the junction of leaf -sheath and lamina (Plate III, fig. 3). The term 

 pulvinus is applied to the swollen growiih zone at the base of the leaf-sheath 

 immediately above the node. The pigment is so concentrated as to appear 

 black unless closely examined. 



In all cases so far noted the two localizations have gone strictly together, 

 forming a single character which is dominant to the unpigmented type. It is 

 probable that a single factor is concerned though it might be a case of complete 

 coupling of two separate factors. 



The figures given in Table X show, approximately, a simple 3 : 1 ratio. 

 There is some variation in the pigmented group which is possibly diie to the 

 heterozygotes being less evenly coloured. This is a matter more of distribution 

 of pigmented cells than of concentration of pigment in the cell. 



Table X. 

 Dark purple colouring of pulrinus and auricle. 



Origin of parent 



Reference 

 No. 



Natural cross 



No. 10, F„ 



Natural crosses . 



10 

 437 

 4.39-N 

 442-N 

 45.3-N 



11 



86 



Pigmented 



Unpigmented 



Total 



Cnlnilnfed 3 : 1 



(g) Fuil-purple self-colour of leaf-sheath. 

 In this character the epidermis of the leaf-sheath is coloured very distinctly 

 purple, especially in the sides and edges. The colouring, although frequently 



