Hi Mark, there are few (very few) people who are experienced in identifying grasses and I know of none near Palmerston North. Colin Ogle in Wanganui could help or it sounds like Pat Enright (Wellington?) knows this species & he may have a photo. You can find images on Google, but use these with caution as the photos in this sort of search are sometimes of another species. I would collect anything that looks like a Trisetum and send it to Kerry Ford at Landcare in Christchurch. See Flora V for a description of the genus, but in general the two bent awns projecting from opposite sides of the spikelet are pretty distinctive.