Theme of appearance and reality. The juxtaposition of the symbols of flower and serpent emphasises the contrast between natural order and her sinful plan. This could be a biblical metaphor: on first glance, some may presume that Lady Macbeth and Eve have a lot in common, however Lady Macbeth seems to be trying to convince Macbeth to go against God - perhaps she's more like the serpent. Could suggest that Macbeth is symbolic of Eve - opening up the Jacobean criticism of Macbeth that he is too feminine. In Genesis, Eve is the one considered to be more at fault, and typically Lady Macbeth is also, so this could depict Lady Macbeth as both Eve and the serpent.