APPENDIX 343 



The members of this series can enter into nine different combina- 

 tions, and each of these denotes another colour — 



1 AiA t 2 A x aA 2 1 A 2 a 



2 A\A 2 a 4 AiaA 2 a 2 A 2 aa 

 1 A\a 2 A\aa 1 aa. 



The figures prescribed for the separate combinations also indicate 

 how many plants with the corresponding colouring belong to the 

 series. Since the total is sixteen, the whole of the colours are on the 

 average distributed over each sixteen plants, but, as the series itself 

 indicates, in unequal proportions. 



Should the colour development really happen in this way, we 

 could offer an explanation of the case above described, viz. that the 

 white flowers and seed-coat colour only appeared once among 

 thirty-one plants of the first generation. This colouring appears 

 only once in the series, and could therefore also only be developed 

 once in the average in each sixteen, and with three colour char- 

 acters only once even in sixty -four plants. 



It must, nevertheless, not be forgotten that the explanation here 

 attempted is based on a mere hypothesis, only supported by the 

 very imperfect result of the experiment just described. It would, 

 however, be well worth while to follow up the development of 

 colour in hybrids by similar experiments, since it is probable that 

 in this way we might learn the significance of the extraordinary 

 variety in the colouring of our ornamental flowers. 



So far, little at present is known with certainty beyond the fact 

 that the colour of the flowers in most ornamental plants is an 

 extremely variable character. The opinion has often been ex- 

 pressed that the stability of the species is greatly disturbed or 

 entirely upset by cultivation, and consequently there is an inclina- 

 tion to regard the development of cultivated forms as a matter of 

 chance devoid of rules; the colouring of ornamental plants is indeed 

 usually cited as an example of great instability. It is, however, not 

 clear why the simple transference into garden soil should result in 

 such a thorough and persistent revolution in the plant organism. 

 No one will seriously maintain that in the open country the 

 development of plants is ruled by other laws than in the garden 

 bed. Here, as there, changes of type must take place if the condi- 

 tions of life be altered, and the species possesses the capacity of 

 fitting itself to its new environment. It is willingly granted that 



