Koru . . .

A fern frond unfurling... The koru is the name given to the new unfurling fern frond and symbolizes new life, growth, strength and peace. It is an integral symbol in Māori carving and tattoos.

The koru is used in a stylized form as the logo of Air New Zealand and as an iconic symbol of New Zealand flora.

Koru can also refer to bone carvings. Those generally take the shape of the uncurling fern plant. When bone is worn on the skin, it changes color as oil is absorbed. The Māori took this to symbolize that the spirit of the person was inhabiting the pendant. When someone gives a pendant to someone else, it is the custom that they wear it for a time so that part of their spirit is given as well. This one is carved from green stone (jade) which is found here in New Zealand. 

This is a famous portrait of a tattooed Māori and a wood carving. Take a look at how similar they are.