My parents didn't really understand the greek system. (My mom grew up in the UK, and my father is anti-greek.) My mom sent me a stuffed giraffe when I was initiated into AEPhi. A sweet gesture.
If I had a daughter about to be initiated into a sorority, I would probably send one of: (a) a bouquet of her sorority's flowers, (b) a bouquet of silk flowers (so that they last a long time), or (c) a cross stitch with the appropriate letters, flowers, symbols, etc.