3i8 CULTIVATED PLANTS AND THEIR ORIGIN 



among crops of green-topped turnips, purple-topped individuals 

 sometimes occur. ' Rogues * most frequently exhibit characters 

 possessed by the ancestors of the variety in which they are 

 found. 



The tendency of plants to revert to long-lost characters is 

 termed atavism, ' throwing-back,' or reversion. 



Very few if any varieties of plants propagated by seeds remain 

 like the type first sent out by the raiser for more than a limited 

 number of years. In a great many instances where almost 

 everybody raises seed, destruction of ' rogues ' is not efficiently 

 or thoroughly carried out, and through the consequent mixing 

 with the progeny of the reverted plants, the type rapidly degener- 

 ates in purity. 



Apart from the incompetence to distinguish slightly reverted 

 forms and laziness in carrying out their destruction, other changes 

 take place in the type through the different ideal which each 

 raiser of seed sets up before his mind when he selects the indi- 

 viduals to be employed as seed parents. For example, three 

 different raisers of seed of ' Gubbins' " Incomparable " pea ' are 

 almost certain to hold different views from Mr Gubbins and 

 from each other in regard to the relative importance of the 

 various characters of a good pea ; selection is therefore carried 

 out from three different standpoints, and in a few generations 

 the ' Incomparable ' variety no longer exists except in name, 

 unless Mr Gubbins himself also carries on the propagation ; three 

 different types bearing the same name would arise. It is there- 

 fore very necessary for the farmer and gardener not to be led 

 away by the fascination of an old name, for it does not follow 

 that anything useful is obtained with it ; at the same time it must 

 be remarked that a new name does not necessarily represent 

 any new quality or character in the seeds to which it is applied ; 

 new names may easily be applied to old articles when the latter 

 cannot be sold by their original names. 



Much valuable experience can be gained by growing small 



