1867.] Relations of Verbasca. 163 



though much more closely allied to the V. thapsus than the others 

 given in Table, are nevertheless least effective in their conjunctive 

 fertility with the latter species. Furthermore, we see by those unions 

 of V, thapsus, liotea, as female, with the yellow and white varieties of 

 Y. lychnitis, and of V. pyramidatum ; that though the pollen of V. 

 pyramidatum is equally potent on the stigma of V. thapsus lutea, as 

 is that of V. lychnitis, alba, there is nevertheless a considerable decrease 

 in the proportionate fertility of the unions with V. lychnitis, lutea. 

 Hence, as we have before shown it to be with the varieties of V. 

 phceniceum, and judging by the physiological test, the V. pyramidatum 

 would interpolate' itself between these slightly different and undoubted 

 varieties of a species. 



In the foregoing Tables, then, I have given nearly all the re- 

 sults of my experiments in the unions of Verbasca. Before 

 considering the nature of the evidence they afford us as to the rela- 

 tionship of mongrelism and hybridism, I will briefly attempt to show 

 how far these results accord with those of Grartner, who has also 

 largely experimented on these plants. I may premise, however, that 

 as my experiments are much less numerous than Gartner's, compris- 

 ing some 57 distinct unions, in which 527 flowers were artificially 

 fertilised, — whereas, as will be seen beneath, Grartner subjected no 

 less than 1085 flowers to experiment, — they would induce very 

 different conclusions, in certain points, to those arrived at by that 

 careful experimentalist. I readily acknowledge therefore the higher 

 claim of the latter to a provisional acceptance, until further experiments 

 show more conclusively their relative correctness. I have also 

 to notice a cause of some little discordance in such a compara- 

 tive examination as that which I am about to institute ; name- 

 ly, that I have given in every case the average number of seeds 

 produced both by pure and mixed unions, whereas Grartner gives the 

 average number of seeds in the pure unions only, taking in each case 

 the maximum or highest number produced by a single capsule in the 

 mixed unions. I was not aware of this peculiarity in Gartner's deduc- 

 tions when I counted the seeds in my own experiments, otherwise, I 

 should have drawn them up for the sake of comparison on a similar 

 basis ; even though I consider it a less fair method than that which 

 I have adopted, in all such cases as the present, in which the ovaries 



