This tī ngahere (forest cabbage tree Cordyline banksii) is a rare plant in Auckland city, but seems happy at home in the Grafton Gully.
These fungus growths on oaks are three species:
The multiple small bracket/polypore is Stereum hirsutem.
The white-edeged one, with soft greens/browns in the rings is Trametes versicolor .
The dark brown ones are Cylcomyces tabacinus.
Check the images module in this story to help with identification. Please note, these fungus species are not edbile.