BI-PARENTAL REPRODUCTION 79 



Presumably the white and yellow kinds have now been 

 fixed by careful and long-continued selection ; and, as a con- 

 sequence, when recapitulation is incomplete the ancestor 

 reverted to is not necessarily one of another colour. In 

 1810-14 Lady Monk and Lord Gambier collected some 

 plants of the wild heartsease, and thus began the cultivation 

 of the modern pansy. Twenty years after " a book entirely 

 devoted to this flower was published, and 400 named varieties 

 were on sale." l Half-a-century later Darwin wrote, " Culti- 

 vators speak of this or that kind as being remarkably constant 

 and true ; but by this they do not mean, as in other cases, 

 that the kind transmits its character by seed, but that the 

 individual plant does not change much under culture. The 

 principle of inheritance, however, does hold good to a certain 

 extent, even with fleeting varieties of the heartsease, for to 

 gain good sorts it is indispensable to sow the seeds of good 

 sorts. Nevertheless, in almost every large seed-bed a few 

 almost wild seedlings reappear through reversion." 2 At the 

 present time the seed of the pansy is " of such a quality, and 

 is saved in so many distinct colours, that for all ordinary 

 purposes the trouble of striking cuttings and keeping stocks 

 in pots all the winter through is mere waste of time and 

 pit-room." 3 



137. An almost endless number of similar examples may 

 be culled from the literature of the subject. It may be 

 accepted as a general rule, therefore, that every variation is 

 unstable in proportion to its newness. It can be " fixed " 

 only by such long-continued selection as makes it occupy a 

 considerable period of the life-history. Otherwise it is apt 

 to be lost altogether through incomplete recapitulation. 



138. In a great number of cases the young plants, grown 

 from the seed of garden plants which have undergone rapid 

 evolution, revert towards the ancestral type. But the 

 recorded instances of the seeds of such reverted plants, or 

 any of their descendants, reproducing the cultivated type are 

 very few if indeed there are any. 4 This must mean that 



1 Animals and Plants, vol. i., p. 392. 2 Op. cit., p. 393. 



3 The Culture of Vegetables and Flmversfrom Seeds and Roots, issued 

 by Sutton and Co., the seed merchants. Messrs. Sutton claim, " In no 

 one department of floriculture has there been accomplished a more 

 remarkable advance, or one tending more directly to the public advan- 

 tage, than in the improvement of the strains and races and stocks of the 

 seeds of Florists' flowers " (p. 195). They give examples of flowers the 

 varieties of which have been recently more or less fixed by selection 

 carried through many generations. 



4 Darwin mentions (Animals and Plants, voL ii., p. 247) that "in 



