Variegated Leaves. 273 
mum sccjctinn, Antirrhinum majus, Polygonwn Fayo- 
p\nim. Linaria I'ulgaris, Silcnc nocti flora etc. 
Hie large scale on which I have conducted my ex- 
periments with Ocnothcra Lamarckiana has enabled me 
to watch the origin of variegated forms in that species 
more closely. Here they appear almost every year from 
green ancestors, and in the most widely different experi- 
mental families and elementary species. 1 Instances of 
it I found in the main Lamarckiana families, first in the 
original wild locality, then in 1889, 1890, 1892, 1895, 
1898 and 1899 in my cultures, arising from series of 
seed-parents which were in every case green plants ; 
also in 0. rubrinervis in 1891, 1893 and 1894; in O. 
laevifolia in 1891, 1894 and 1899; in 0. snbliucaris in 
1896; in O. lata in 1890 and 1899; in O. nanclla in 1890, 
1896 and 1899; in 0. scintillans in 1898 and so on; also 
from the crosses 0. lata X O. cniciata and O. Lamarck- 
iana X 0. Lamarckiana cniciata and others. In 1899 
only eight variegated plants arose in my whole cultures 
which consisted of over five thousand plants of Ocno- 
thcra, that is, between 0.1 and 0.2%. But in the field 
the anomaly was evidently much rarer. 
One of the most striking phenomena presented by 
variegated plants is the so-called twig or bud-variation. 
From a bud a branch arises which is unlike the whole 
of the rest of the plant in the character of its variegation, 
and in this case both variegated plants bearing green 
twigs occur and conversely plants which have hitherto 
been green may bear stray variegated branches. In both 
cases a latent potentiality is manifested. 
The appearance of green branches on variegated 
plants is generally regarded as a case of atavism, that is 
1 See also Vol. I, p. 480. 
