Tepal
A petal-like part of a flower in which petals and sepals look the same.
In some flowers you cannot tell petals from sepals. Both rings have the same colour, size and texture, and botanists call each segment a tepal. A tulip has six tepals: three outer and three inner. Lilies, crocuses, daffodils and magnolias are built the same way. In everyday speech and in flower shops these are simply called petals, and that is fine. The word tepal matters mainly when you are reading a botanical description.