24 



JOUENAL OF THE EOYAL HOETICULTUEAL SOCIETY. 



Ph. multiflorus, but with a more or less pale ground colour ; the fourth 

 plant yielded only one seed of plain brown tint. The forms with pre- 

 ponderantly violet coloured flowers had dark brown, black-bro^\'n, and 

 quite black seeds. 



The trial was continued through two more generations under similar 

 unfavourable circumstances, since even among the offspring of fairly 

 fertile plants there were still some which were less fertile or even quite 

 sterile. Other flower — and seed — colours than those cited did not subse- 

 quently present themselves. The forms which in the first generation 

 contained one or more of the recessive characters remained, as regards 

 these, constant without exception. Also of those plants which possessed 

 violet flowers and brown or black seed, some did not vary again in these 

 respects in the next generation ; the majority, however, yielded, together 

 Anth offspring exactly like themselves, some which displayed white flowers 

 and white seed-coats. The red flowering plants remained so slightly 

 fertile that nothing can be said with certainty as regards their further 

 •development. 



Despite the many disturbing factors with which the observations had 

 to contend, it is nevertheless seen by this experiment that the development 

 of the hybrids, with regard to those characters which concern the form of 

 the plants, follows the same laws as does Pimm. ^Yith regard to the 

 •colour characters, it certainly appears difficult to perceive a substantial 

 agreement. Apart from the fact that from the union of a white and a 

 purple-red colouring a whole series of colours results, from purple to jmle 

 Tiolet and white, the circumstance is a striking one that among thirty-one 

 flowering plants only one received the recessive character of the white 

 •colour, while in Pisum this occurs on the average in every fourth plant. 



Even the^e enigmatical results, however, might probably be explained 

 by the law governing Pisiim if we might assume that the colour of the 

 flowers and seeds of Ph. niultifloriis is a combination of two or more 

 entirely independent colours, which individually act like any other 

 constant character in the plant. If the flower colour A were a combina- 

 tion of the individual characters A 1 -I-A2+ . • • which produce the total 

 impression of a purple colouration, then by fertilisation with the differentiat- 

 ing character of the white colour a there would be produced the hybrid 

 unions A . a + Aga -f . . . and so would it be with the corresponding colouring 

 of the seed-coats. According to the above assumption, each of these hybrid 

 colour unions would be independent, and would consequently develop quite 

 independently from the others. It is then easily seen that from the 

 combination of the separate developmental series a perfect colour- series 

 must result. If, for instance, A=Ai-f Ag then the hybrids Aia, and Aaa 

 form the developmental series — 



Ai + 2Aia-f a 

 A2 + 2A2a + a 



The members of this series can enter into nine different combinations, 

 and each of these denotes another colom: — 



1 AjA2 2 AjaA2 1 A 9a 



2 AjAoa "4 A|aA2a 2 Aoaa 

 1 A I a 2 A ] aa 1 aa 



