Arthothelium spadiceum (C.Knight) Müll.Arg.
Lectotype: New Zealand. Sine loco?Wellington. Charles Knight, BM!
Thallus greyish or glaucous grey to grey-white in patches on smooth bark 3-4 cm diam., delimited by a thin black line, thin, rather roughened, cobwebby or ± cracked in parts. Ascocarps innate pale red-brown to yellowish-brown, 0.5-1.0 mm diam., rounded or oblong or occasionally ± irregular, disc roughened or ± granular, flat, K+ purple. Ascospores ovate to oblong, brown, 10-locular, 40 × 18 µm.
N: Known only from the type collection.
Endemic