Leake and ram prasad. 57 



Opportunity for collecting evidence on this head has been limit- 

 ed, but it is satisfactory to find that, to prevent cross-fertilisation 

 as far as it is possible to draw any conclusion, such distances appear 

 to be unnecessary. Such observations as have been obtained 

 are derived from the 1910 series (early) grown from naturally 

 fertilised seed. In this series, using the red sap, and the flower 

 colour as distinctive characters, the number and character of the 

 crosses occurring in the of!spring of each individual separately has 

 been recorded, and the position of each parent plant in the field 

 then traced back and a note made of its distance from the nearest 

 plant capable of giving the particular cross observed. Such details 

 have been obtained for some eighty plants and their respective 

 offspring and tabulated in Table VI while the method is illustrated 

 in Diagrams 1 — 4. 



In the field the plants were ranged in lines 3ft. apart with a dis- 

 tance of 2ft. 6in. between the plants in a single line. Each plant, 

 therefore, is surrounded by eight plants, two at a distance of 2ft. 

 6in., two at 3ft. and four at a distance approximately 3ft. lOin. 

 These eight plants form an inner circle of neighbours and their bran- 

 ches may intermingle with those of the central plant. In no other 

 case will such intermingling occur though, if the intervening plant 

 dies, a short distance only will separate the plant from plants se- 

 parated by a distance of 5ft. in one direction or 6ft. in the other. 



Table VI may, therefore, be considered as falling into 3 sections : 

 — the first includes all those plants situated within four feet of each 

 other ; the second, those separated by a distance greater than four 

 feet but less than 10 feet ; and the third, those separated by 10 feet 

 or more. In the first case, as the table shows, crossing occurs with 

 considerable frequency and the same remark applies to the second 

 gi'oup. In the latter case, however, with one exception (Diagram 

 3), the intervening plants have died, and there is, therefore, direct 

 access from one plant to the other. In the third group, if the off- 

 spring of a single plant are excluded, no crossing has taken place. 

 In the exceptional case (Diagram 2) distinction can be drawn be- 

 tween the three crosses. In two of them, in addition to the yellow 



