160 On the Reproductive Functional [No. 3, 



potency of the two pollens on the stigmas of V. blattaria, lutea, 

 are much less than those we have above noticed when V. blattaria 

 alba is used as female ; and also that the potency of the two pollens 

 is greater on the stigmas of the yellow than those of the white variety 

 of V. blattaria lutea ; and again that the white variety of V. thapsus 

 is more fertile than the yellow, in their respective unions with the 

 V. blattaria, alba. Thus V. blattaria, lutea, by pollen of V. thapsus, alba, 

 gives an average fertility of 61 ; by pollen of V. thapsus, lutea, 50, 

 relatively to 90, the product of fertilisation by its own pollen. Lastly, 

 we have the different unions of the two pollens of the white and 

 yellow V. lychnitis on the stigmas of the yellow and white varieties 

 of V. blattaria. In these unions we see first that with V. blattaria, alba 

 as female, the pollen of the white variety exceeds that of the yellow 

 in the proportion of 36 : 23 ; secondly, with the V. blattaria, 

 lutea, as female, the pollen of the white variety is again singularly 

 enough the more fertile, exceeding that of the yellow variety, in 

 the proportion of 45 : 41. Thirdly, we find that here also the yellow 

 variety of V. blattaria yields a higher degree of fertility, — taking the 

 conjoint products of the two unions with the pollen respectively of 

 V. thapsus, lutea and alba, — than the white variety of V. blattaria when 

 similarly treated, the proportions being as 70 of the V. blattaria to 47 

 of the V. blattaria, alba, or nearly as 3 : 2. 



This leads me to notice a curious fact prominently brought before 

 us in the above Table, whatever may be its real signification, namely, 

 that the yellow varieties of V. lychnitis and blattaria, though yielding 

 a higher grade of fertility to the pollen of the white and yellow 

 varieties of distinct species than do the respective white varieties 

 of the above species when similarly fertilised, are nevertheless less 

 productive of seed than the white, when both are fertilised with their 

 own pollen. This will be seen by consulting the following tabular 

 arrangement, in which I have given a reduced approximate of the 

 relative fertility of the different unions, selecting from the hybrid 

 unions in each instance only the most fertile. 



1. V. lychnitis, alba, by own pollen is as 83 : 75 of V. lychnitis, 

 lutea, by its own pollen. 



2. V. lychnitis, alba, by pollen of V. lychnitis, lutea, is as 68 : 71 

 of V. lychnitis, lutea, by pollen of V. lychnitis, alba. 



