Naked kidney lichen is a folios lichen with apothecia that are common, stalkless, and embedded on the lower surface. The reddish-brown discs are visible as the thallus lobes curl backward. The thallus is foliose with round, wavy, and curled lobes ascending. The upper surface is whitish-tan to olive or dark brown, mostly smooth though sometimes with a network of ridges, the lower surface is pale brown and hairless.
It can be distinguished N helveticum because it is hairless vs has fine hairs on the underside of the thallus. N parile has soredia on the lobe margins while N bellum does not have soredia.
