Holotype: 17455, on unknown woody substrate, 1914, Manaku Forest, Auckland, New Zealand, W. N. Cheeseman, in herb. K; isotype in herb. PDD.

Basidiocarps adherent, broadly effused, membranous to ceraceous, smooth, up to 1 mm thick; fertile area "greyish orange" (near 5B4), not changing color in KOH; margin abrupt, not differentiated; subiculum pale yellow, very thin, often not observable. Hyphal system monomitic. Subiculum sparse, not evident in many sections, hyphae 4-6.5 µm diam, thin walled to firm walled, yellow, with regular branching at right angles, smooth or coated with orange granules that frequently dissolve in KOH turning solution yellow, simple septate; subhymenium making up most of thickness, with hymenial elements imbedded at all levels, hyphae 3-4.5 µm diam, hyaline, thin walled; cystidia of two kinds, some subulate and mostly smooth or only lightly covered with orange granules, with most granules dissolving in KOH; some heavily encrusted and cylindrical, 35-65 x 4-6 µm (-9 µm when heavily encrusted), thin walled or with only slight thickening, with rare secondary septa, embedded at all levels, the embedded ones with orange crystals, persistent even in KOH; basidia cylindrical, 40-50 x 5-6 µm, thin walled, hyaline, 4-sterigmate, sterigmata up to 3.5 Itm long; basidiospores ellipsoid to narrowly ellipsoid, 5-5.5 x 2.5-3 µm, hyaline, smooth, thin walled, Melzer's -, acyanophilous.

New Zealand, known only from type collection.

On bark of dead branches.

Discussion: The only Phanerochaete species with which P. luteo-aurantiaca could be confused is P. ericina. Phanerochaete luteo-aurantiaca is distinguished by cystidia encrusted with orange crystals or granules and by the absence of the much branched binding-type hyphae present in P. ericina.

UNKNOWN HOST. Auckland, Mamaku Forest, W. N. Cheesman, 1914 (type collection, in herb. Kew).

Hymenophore perennial, membranous-ceraceous, adherent, effused forming irregular areas to 8 x 5 cm; hymenial surface at first pallid orange, drying ochre, even, not creviced; margin thinning out, isabelline, or abrupt and cliff like when dark brown. Context isabelline, 300-750 µm thick, of several obscure zones, basal layer of compact intertwined hyphae, intermediate layer of compact erect hyphae embedding metuloids and at the base masses of crystals; generative hyphae 5-6 µm diameter, walls 0.2 µm thick, hyaline, many encrusted in part with granules of mucilage, crystals, or both, staining blue, without clamp connections. Metuloids arranged in 3-7 irregular rows in the context, some projecting to 35 µm, fusiform or aculeate, 40-55 x 5-8 µm, encrusted on the upper third with orange or yellow masses of mucilage granules or calcium crystals. Hymenial layer to50 µm deep, a dense palisade of basidia, paraphyses, and metuloids. Basidia subclavate, 14-25 x 5.5-6 µm, bearing 4 spores; sterigmata erect, slender; to 5 µm long. Paraphyses cylindrical, 18-24 x 3.5-4 µm.Spores elliptical, 4.5-5 x 2.5-3 µm, walls smooth, hyaline, 0.1 µm thick.

DISTRIBUTION: New Zealand.

HABITAT: Effused on bark of dead branches.

Only the type collection has yet been found. Metuloids are encrusted on their upper third with either granules of yellow or orange mucilage, or calcium crystals, sometimes both being present on the same metuloid. Similar crystals and granules are present on portions of the context hyphae. Because of the bright colour of granules, metuloids are readily seen in sections. According to E. M. Wakefield granules are soluble in alkalies, producing a bright yellow solution.

TYPE LOCALITY: Rotorua, Auckland, New Zealand.

[Notes from Kew Type specimen, PRJ 2010] Kew images.

Fungus efusus, tennis, ceraceus. Hymenium sulphurinum vel ochraceo-aurantiacum, laeve; subiculum ambitusque albida. Basidia clavata, 4-sterigmatica, 30-40 x 6-7 µ. Adsunt quoque cystidiola numerosa, subulata, apice acuta, granulis aurantiacis incrustata, alia obducta, alia usque ad 36 µ emergentia, 45-50 x 4-5 µ. Sporae oblongae, hyalinae, 5 x 2.5-3 µ, uniguttulatae. Hyphae basales hyalinae, granulis luteis leviter incrustatae, valde ramosae, septatae, diametro.

A beautiful and conspicuous species with its bright yellow colour varying to tawny orange. In the possession of slender crystidioles [sic], it is allied to C. ochraceo-favum Bourd. & Galz.; but it differs in the more brilliant colouring and softer (less horny) consistency when dry. The colouring matter is soluble in alkalies, forming a bright yellow solution.

Hab. On wood; Mamaku, near Rotorua, New Zealand.