Variegated Leaves. 277 



way in this case as in that of the striped flowers. The 

 buds in the axils of the leaves on the variegated sectors 

 usually produce variegated branches, but those of the 

 green sectors green ones. Breeders take this fact into 

 consideration in the choice of buds for use in the multi- 

 plication of variegated forms, as we have already seen.^ 

 It seems that the bud-variations, that is to say both the 

 progressive (producing variegation) and the retrogres- 

 sive or atavistic ones, are generally the result of a pre- 

 ceding sectorial variation. But in most cases all traces 

 of the latter are soon lost. In Quercus pediincidata I ob- 

 served, as I have already mentioned, a variegated twig 

 on a green bush. In this case the variegation extended 

 on to the bark and the color of the branches of the pre- 

 ceding years could thus still be recognized. The main 

 branch proved to be unilaterally variegated and the varie- 

 gated twig arose from this side. The branches at the 

 other side were green (Hilversum 1886). When the 

 leaves are arranged in two rows as in Castanca irsca, 

 UUniis caiiipestris etc. the leaves on one side of the 

 branch may be variegated and on the other, green. In 

 such cases I found the lateral twigs on the older parts 

 on the green side to be entirely green and those on the 

 variegated side entirely variegated ; but I might repeat 

 here that there is still a tendency in the green branches, 

 even if only a slight one, to produce variegated leaves. 

 The contrast between green and variegated is therefore 

 not nearly so great as would appear at first sight. 



We have now to consider the question of the in- 

 fluence of external conditions on the degree of variega- 



apical cells would be of great interest, especially in the Conifers and 

 vascular Cryptogams (e. g., Junipcrus, Adianthuin, Selagiiiclla etc.). 



* See Salter's method, Vol. T, Part I. p. 147. 



