Flora of New Zealand Series

Holotype: New Zealand. Sine loco [probably Wellington], 25.xi.[18]77, Charles Knight s.n. – WELT [specimen annotated as Arthonia ampliata Kn. & Mitt. khija & Patwardhan 1995a: 208)].

Description : Thallus crustose, greyish white, areolate, delimited by a marginal black prothalline line, corticolous, epiphloeodal. Apothecia black, epruinose, emergent, to 1.0 mm diam. Epithecium dark-brown to blackish brown, 23–36 μm thick. Hymenium bright orange-yellow, 66–100 μm tall. Hypothecium concolorous with hymenium or slightly darker, 30–45 μm thick. Asci subglobose. Ascospores 8 per ascus, colourless, muriform, transversely 4–6-septate, vertically 1–3-septate, without a terminal undivided cell, 29–36 × 13–16.5 μm.

Chemistry : TLC−, all reactions negative.

N: Known only from the type locality.

Endemic

Illustrations : Makhija & Patwardhan (1995a: 211, figs 11, 12).

A. endoaurantiacum is based on material collected by Charles Knight and annotated by him as Arthonia ampliata C.Knight & Mitten  Arthothelium ampliatum). It differs, however, from A. ampliatum, and all other known species of Arthothelium by the combination of a bright, orange-yellow hymenium; a blackish brown epithecium, and the absence of an undivided, large, terminal cell in the ascospores.