Variegated Leaves. 283 



sometliing else is necessary, and this something chance 

 alone can. provide, \\niat we want is the transition frnm 

 one race to another, a transition, which according tu my 

 opinion, cannot be effected gradually, but takes place 

 suddenly from as yet unknown causes; we have, in fact, 

 to wait for a mutation. 



The longer a variegated plant has been in cultiva- 

 tion the more strongly does the fact that it has not pro- 

 gressed support this conclusion. The best instance is 

 afforded by the familiar Rocket^ which is one of the 

 oldest, favorite and most widely distributed variegated 

 plants in cultivation, and which is often seen to escape 

 from gardens (Barbarea vulgaris variegata). The plant 

 is cultivated almost solely for its variegated leaves, al- 

 though it is a kind of cress. It is biennial and sufficiently 

 constant ; it is usually grown from seed, although it can 

 also be propagated by division. Only a small percentage 

 of the seedlings are found to be variegated. Amongst 

 a thousand growni from seeds which I had harvested 

 myself from isolated variegated plants, I found only 

 one per cent variegated and ninety-nine per cent plants 

 whose cotyledons and first leaves were pure green. No 

 white or yellow seedlings occurred. Of the greens a large 

 proportion developed later into variegated plants, as was 

 to be expected." But the variety can by no means be 

 regarded as fully fixed. 



Very many variegated varieties, especially of annual 

 and biennial plants, come true to seed. AIorren, Car- 

 RiERE'*^ and other authors have drawn \\\) lists, and much 

 information relating to the subject can be gathered from 



^ Vilmorin-Andrieux, FIcui's dc plcinc tcrrc. p. 387. 



^According to Morren. Hcrcditc, Inc. ci'f.. p. 229, from 70-90% 

 of the seedlings become variegated in later life. 



^ E. A. Carriere, Prodttctinu rf fixation drs varictcs, 1865. p. 14. 



