394 MEANS OF CROSS-FERTILISATION. Chai>. X, 



plant is highly fertile when insects are excluded. Now 

 several flowers on a remarkably constant whitish variety 

 were fertilised without being castrated with pollen from 

 a yellowish variety ; and of the twenty-eight seedlings 

 thus raised, every one bore yellowish flowers, so that 

 the pollen of the yellow variety completely overwhelmed 

 that of the mother-plant. Again, lleris umbellata is 

 spontaneously self-fertile, and I saw an abundance of 

 pollen from their own flowers on the stigmas ; neverthe- 

 less, of thirty seedlings raised from non-castrated flowers 

 of a crimson variety crossed with pollen from a pink 

 variety, twenty-four bore pink flowers, like those of the 

 male or pollen-bearing parent. 



In these two cases flowers were fertilised with pollen 

 from a distinct variety, and this was shown to be 

 prepotent by the character of the offspring. Nearly 

 similar results often follow when two or more self-fertile 

 varieties are allowed to grow near one another and are 

 visited by insects. The common cabbage produces a 

 large number of flowers on the same stalk, and when 

 insects are excluded these set many capsules, moderately 

 rich in seeds. I planted a white Kohl-rabi, a purple 

 Kohl-rabi, a Portsmouth broccoli, a Brussels sprout, 

 and a Sugar-loaf cabbage near together and left them 

 uncovered. Seeds collected from each kind were sown 

 in separate beds ; and the majority of the seedlings in 

 all five beds were mongrelised in the most complicated 

 manner, some taking more after one variety, and some 

 after another. The effects of the Kohl-rabi were 

 particularly plain in the enlarged stems of many of the 

 seedlings. Altogether 233 plants were raised, of which 

 155 were mongrelised in the plainest manner, and of 

 the remaining 78 not half were absolutely pure. I 

 repeated the experiment by planting near together 

 two varieties of cabbage with purple-green and white* 



