SPECIMENS EXAMINED: NORTHLAND: Whangarei, Western Hills, on Leptospermum scoparium, J. M. Dingley, Jun 1948, PDD 6586; Waipoua Forest Sanctuary, Yakas Kauri Track, on Beilschmiedia taraire, P. K. Buchanan 951134 & L. Ryvarden, 11 Apr 1995, PDD 70909; ibid., P. K. Buchanan 951141 & L. Ryvarden, PDD 70910; Bay of Islands, Opua Forest, L. Ryvarden 37392, 12 Apr 1995, O, PDD 70908. AUCKLAND: Waitakere Ranges, Karekare, on Coprosma robusta, J. M. Dingley, Sep 1946, PDD 6589; Waitakere Ranges, Kitekite Tr., on wood, P. K. Buchanan 891044, PDD 58375. COROMANDEL: Little Barrier I., on Kunzea ericoides, J. M. Dingley, Nov 1947, PDD 6588. TARANAKI: Te Maire, on wood, J Bedford, 28 Aug 1985, PDD 52440.

Basidiocarps annual or sometimes reviving for second year, resupinate to effused-reflexed with lobed pilei, resupinate portion to 9 x 5 cm or sometimes extending along a branch (e.g., to 20 x 3 cm) but often much smaller, up to 6 mm thick in central part; reflexed surface cream to bright yellow (86.1.Y - 83.brill.Y), fading in part to yellow- or orange-brown on drying, scrupose to finely tomentose or glabrous, concentrically zonate; pore surface bright yellow (83.brill.Y) especially in young material, otherwise cream and may stain yellow bright yellow colour in part remaining on drying o fading to pale yellow-brown (73.p.OY), with whit to pale yellow sterile margin to 1 mm wide; pore angular, with thin dissepiments, 7-9 per mm; tube to 4 mm deep in a layer; context white though often yellow towards substrate in older specimens, to 1 mm thick. Hyphal system dimitic; generative hyphae with clamps, hyaline, 2-3.5 µm and thin-walled in trama, 2.5-6 µm diam. with thickened wall in context, sometimes in context contorted and frequently branched; skeletal hyphae unbranched, hyaline, thin to thick-walled (to 1.5 µm) and always with distinct lumen, IKI-, with occasional adventitious simple septa, 2-4 µm diam. in trama, 2.5-6 µm diam. in context. Cystidia absent. Basidia clavate, 4-sterigmate, with a basal clamp, 9-14 x 3.5-4.5 µm. Basidiospores ellipsoid, hyaline, thin-walled, smooth, IKI-, 2.5-3 x 1.2-1.5(-1.8) µm. Causes a white rot, with wood sometimes staining yellow.

New Zealand and Australia.

SUBSTRATA: On dead hardwoods: Beilschmiedia, Coprosma, Kunzea, and Leptospermum.

NOTES: A. citrea is characterised by a bright yellow, smooth pileus surface, a yellow to cream pore surface with tiny pores almost invisible macroscopically, and small basidiospores. Although the species was recorded previously in New Zealand, its taxonomy has been confused. The description of the type specimen of A. citrea, and additional material from Australia (Ryvarden 1984) accord with descriptions of New Zealand and Australian material of Leptoporus coriolus (Reid 1963; Hood 1992) and of Tyromyces semisupinus sensu G.Cunn. (Cunningham 1965), and is confirmed by our observation of herbarium material under these names. Collections identified by Cunningham as T. semisupinus can be readily differentiated from Antrodiella semisupina (Berk. & M.A.Curtis) Ryvarden (Ryvarden & Gilbertson 1993), and from related species (Vampola & Pouzar 1996), by their citric yellow pileus surface and the dimitic hyphal system. A. semisupina sens. str. is not known from New Zealand.
The name Tyromyces citreus (Berk.) G.Cunn. was misapplied by Cunningham (1965) for New Zealand and Australian collections that differ from A. citrea in having flabelliform rather than effused-reflexed basidiocarps, and larger pores, basidia, and spores. Further evaluation of Cunningham's material labelled T. citreus is required (Ryvarden 1984; Hood 1992).
We consider that the species is correctly placed in Antrodiella Ryvarden & I.Johans. rather than in Leptoporus Quel. (Reid 1963) since the latter is characterised by a monomitic hyphal system with simple septate hyphae and a brown rot (Ryvarden 1991). A. citrea is similar to another species with yellow pores, A. citrinella Niemela & Ryvarden, but the latter has larger pores, 3-4(-5) per mm, and larger spores, 3-3.5 x 2-2.5 µm (Ryvarden & Gilbertson 1993).