Variegated Leaves. 283 
something else is necessary, and this something chance 
alone can provide. What we want is the transition from 
one race to another, a transition, which according to my 
opinion, cannot he effected gradually, hut 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 1 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 vidgans 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 grown 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 he expected. 2 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. MORREN, CAR- 
RiERE 3 and other authors have drawn up lists, and much 
information relating to the subject can be gathered from 
1 VILMORIN-ANDRIEUX, Fleurs de pJcine terre, p. 387. 
2 According to MORREN, Hercditc, he. cit.. p. 229, from 70-99% 
of the seedlings become variegated in later life. 
3 E. A. CARRIERE, Production et fixation des varictcs, 1865. p. 14. 
