488 JOURNAL OF THE ROYAL HORTICULTURAL SOCIETY. 



to be in the former generation, then in this generation it should behave 

 really as a first hybrid character, say intermediate between the size of 

 1 British Queen ' and ' Eclipse.' Judging, as before, the size by the 

 weight, I found that six of the largest ' British Queen ' seeds just 

 balanced sixteen of the largest ' Eclipse,' while in these hybrids I find 

 that it takes eight of the largest seeds to balance either the six 'British 

 Queen ' or the sixteen ' Eclipse.' If the hybrid seeds were exactly inter- 

 mediate between the parents, the ordinary mean would be 11, and the 

 true mean 9*7, so that broadly speaking the hybrid size favours the 

 • British Queen ' parent slightly more than the 1 Eclipse.' But there are 

 other complications which may possibly account for this departure from 

 the mean ; for instance, all these hybrid seeds were borne on extra- 

 ordinarily vigorous hybrid plants seven to eight feet high, in which the 

 tall 6^-feet 1 British Queen ' parent was distinctly dominant over the 

 dwarfer 2^-feet 'Eclipse' parent, thus again confirming Mendel's 

 experience, in which the tall character was always dominant over the 

 short character. 



This was the case with all my twelve hybrids (Experiments 2-1 8), 

 and, just as Mendel found, the dominant hybrids exceeded in height and 

 vigour the pure dominant parent (Mendel 1865, Bateson 1901). It 

 seems reasonable to suppose that such extra vigour in the hybrids would 

 affect the size of the seeds borne thereon. It may also be worthy of note 

 that the flowers of the hybrids (Experiments 2-13) were precisely similar 

 to those of the 1 British Queen,' having the large, substantial, pure white 

 flowers of that parent, with no trace of the small, semi-transparent, 

 greenish- white flowers of the ' Eclipse.' 



These comparisons were made at the same time, all the plants, 

 hybrids and parent races, being grown side by side in similar soil, being 

 practically under the same conditions of life. 



Cotyledon Colour. 



Although seed shape in Peas depends on the shape of the cotyledons, 

 it can be easily determined without removing the seed-coat or outer skin. 

 On the other hand, in some races the cotyledon colour is masked by the 

 nr re or less thick and pigmented seed-coat. 



In gardens, it is customary to divide ordinary Peas into " green," 

 " white," and " blue." The " white " Peas have usually yellow cotyledons, 

 and the "green" ones green cotyledons; but in s_me cases "green" 

 varieties with a thick green skin have yellow cotyledons: "blue" Peas 

 have usually green cotyledons seen through a semi-transparent skin. 

 It is, therefore, not at all safe to judge the cotyledon colour in all races by 

 the outward appearance of the seed ; and in order to determine the coty- 

 ledon colour in the thick-skinned races, the seed-coat has to be removed. 



If this be done entirely the germination of the seed is naturally 

 affected, so that in these experiments it was thought desirable to select 

 races whose seed-coats were more or less transparent. In ' British Queen ' 

 we have a "white" deed with yellow cotyledons obscurely seen through 

 a white seed-coat ; in ' Eclipse ' we have a " blue " seed with green cotyle- 

 dons more clearly seen through a white seed-coat. In both cases the seed- 



