On the Genetics of Tetr aphid Plants in P. sinensis. 487 



respect of which giant intermediates have been produced, include both 

 morphological characters and colour-characters. They are — 



During the present year there have also been obtained some flower-colours 

 which are intermediate between magenta and red, but, as the diploid races 

 also produce certain colours which it is difficult to classify, further experi- 

 ment is necessary to show whether or not the new kinds of colour are 

 peculiar to the tetraploid races. 



With regard to the characters (1), (2), and (3) above, it should be pointed 

 out that dominance is incomplete in the diploid races, but the giant 

 intermediates form a distinct class from the common heterozygous type, 

 which also occurs in the giant families, alongside of the peculiar intermediate 

 types. 



The intermediates between the palmate and fern leaves are, however, the 

 most striking, because in the diploid races the dominance of the palmate 

 shape is, for practical purposes, complete. 



In all the cases there is some range of variation among the intermediate 

 forms, and there may be differences of degree between the different organs of 

 the same plant. 



Further, it has been found that in the tetraploid giants certain types of 

 flower-coloration may occur, which closely resemble the colours of certain 

 diploid pure races, but are, nevertheless, the product of a different set of 

 factors. This may be simply illustrated in the case of a Giant Eed with red 

 stigma, which almost exactly matched the colour of my Eed Stellata non- 

 giant race. The non-giant race is quite pure, and contains no colour- 

 inhibiting factors. The giant red, selfed, has given (1) forms like itself,. 

 (2) more deeply coloured forms, and (3) pure and heterozygous " Duchess " 

 types, that is to say, types showing the possession of the factor which 

 inhibits the production of colour in the peripheral regions of the flower. 

 Other similar cases have occurred, both in plants with green stigmaa 

 {i.e. possessing the factor which inhibits colour in the central parts of the 

 flower), as well as in those with red stigmas. These cases, then, provide the 

 striking result that the coloured form is shown to be capable of throwing 

 the doviinant white. 



VOL. LXXXVII. — B. 2 O 



Dominant Character. 

 (1) Petals cut at the edges. 



Petals heart-shaped with simple 



Recessive Character. 



(2) Tie-ring habit of the inflorescence. 



(3) Palmate leaves. 



(4) Dominant white. 



median notch. 

 Inflorescence condensed. 

 Pern leaves. 

 Coloured flowers. 



