LEAKE AND RAM PRASAD 129 



appears, however, that the determination so made is not invariably 

 correct and the method is subject to an error of 22 per cent. 

 A more accurate method has been found for this determination in 

 the young leaves. The red colouring matter in the leaf, from the 

 time this first opens until full development is reached, has been 

 found to have a different distribution which varies with the intensity 

 of the colour. In those plants in which this is developed in greatest 

 intensity the entire leaf, ribs, veins and lamina, are all suffused 

 with a deep red colour. With a diminished intensity the colour 

 becomes restricted to the ribs and veins and, in limiting cases, to 

 the ribs only. These three stages have received the notation of 

 colour to lamina, to veins and to ribs respectively. Plate XIV 

 illustrates 3 examples — the parents of a cross between a pure red 

 form (Type 3) and a form in which the colour is absent (Type 9) 

 with the F^ in which the colour extends to the ribs. In Table \' 

 are collected the records of the determinations of the colour in the 

 young leaf from which it appears that the error is reduced to slightly 

 under 7 per cent. 



A series of crosses have been made between Type 3, bearing 

 the red colour, and types in which this is absent and the behaviour 

 of this character may be most readily considered in conjunction 

 with that of the petal colour. 



In the cross between Type 3 and Type 4 both parents bear the 

 yellow factor, and in this case a simple pair of allelomorphic charac- 

 ters is under consideration. 



In the crosses between Type 3 and the two Types 7 & 9, the 

 yellow factor is present in Type 3 only, while in the cross between 

 Type 3 and Type 10 the yellow factor is again present in Type 3 

 only, but the case is complicated by the presence of the pale-yellow 

 factor of Type 10. 



Such crosses between a red sap coloured plant (Type 3) and 

 one in which this colour is absent have been more than once at- 

 tempted by other investigators. The earliest on record is that 

 made by Major Trever Clarke in 1867 (Watt 32, p. 336). Refer- 

 ences to these experiments are scattered throughout the Journal of 

 the Agri. Horticultural Society of India for that period as also in 



