Close-up of the variegated leaf of the Aurora poplar tree, Populus x candicans 'Aurora'. The appearance of the leaf is due to the presence of varying amounts of the green pigment chlorophyll in the chloroplasts of the leaf cells. Each leaf is different in detailed appearance, the pattern of pale and dark cells reflecting the patterns of cell division during its growth and development. Thus a cell which turned white early in the leaf's development will produce a large patch of white tissue after it has divided many times. There are various causes of variegation in different plants; this is an example of cell lineage variegation.