PURPLE SHAMROCK

Heh! Heh! Heh! I sort of expected that a 'plant fairy' would tell me the name of the plant that I was searching for. So it seems that my mum's butterfly plant is called purple shamrock as it appears to be similar to the shamrock which is green in colour. It is also known as False Shamrock, Oxalis plant and Love plant. The scientific name is Oxalis triangularis. From the information that I got, it seems that this plant can be eaten.

Reference: http://en.wikipedia.org/wiki/Oxalis_triangularis