One of its races - we actually don't have this species in the strict sense in New Zealand. I looked at your specimen and this determination was confirmed by Dr Dan Blanchon. Your sample is being DNA sequenced so we may have more to report in due course
Foliose lichen, thallus white above when dry, narrowly lobate, dividing randomly, not faveolate. Underside very black, sorediate with numerous rhizines which project right to the margins and are visible from above. Underside newer growth light brown but quickly turning black, maculate with white specks. Medulla white. Fringe of ultramafic zone on rocks.