280 Non-Isolahle Races. 



plants are often entirely green during years of improper 

 treatment, but with due care can be restored to the varie- 

 gated condition.^ 



The degree of variegation is not only dependent upon 

 the conditions of growth but also on the time of the year. 

 If we look closely at variegated plants in green-houses 

 we shall see that the branches which arise in summer are 

 beautifully flecked, whereas those which arise in \vinter, 

 w^hen they get less light, are much greener and sometimes 

 even quite green. This at least is true in our climate ; 

 but one must remember that the leaves formed in sum- 

 mer remain on the shrubs through the winter, and 

 undergo no further change in their variegation. There- 

 fore it is not the general appearance which is dependent 

 on the time of the year. Ouercus pednncidata argcnteo- 

 picta is green in spring, but becomes white or variegated 

 later on.^ Young plants are often still green in spring 

 even .though later they may become variegated, as for 

 instance, Symphytum, Barharea vulgaris, etc.*^ I have 

 observed in a culture of Gciim nrhamim, which I have 

 kept up during several years, that the variegated speci- 

 mens gradually develop green leaves in the autumn and 

 lose the variegated ones. In winter they were almost 

 completely green, but as soon as life awoke in the spring 

 they began to develop flecked leaves again, and through- 

 out the whole summer they were fully variegated. They 

 behaved in this way throughout every winter of their 

 life. On the other hand a variety of the ornamental 

 curly cale with yellow-veined leaves is beautifully varie- 



* Verlot, loc. cit., p. 75. 



'L. Beissner, Knospcnvariation, IMittli. d. deutsch. Dendrolog. 

 Gesellsch., No. 4, 1895. 



' Verlot, loc. cit., p. yS. 



