As far as I can tell 'nothing' but on the Chatham Islands this species was known as 'toitoi' by Moriori and there is some suggestion (on herbarium specimens collected by Travers) that they used it as a thatch for their whare - which makes sense as it is very common on those islands. Their name has since become confused with 'toetoe' the Maori name for a very different species on the Chatham's - Austroderia (Cortaderia) turbaria and in New Zealand proper (other Austroderia species). Hope this helps