Agathis australis Salisb. Auckland: Titirangi, Waitakeres, 900ft., April, 1947, J.M. Dingley; Waipoua Kauri Forest, April, 1947, J.M. Dingley; Huia, July, 1947, J.M. Dingley, type collection, P.D.D. herbarium, No. 5568; same locality, October, 1953, J.M. Dingley; Puketi Forest, Bay of Islands, June, 1948, J.M. Dingley; Clevedon, August, 1949, J.M. Dingley; Huia, 100ft., January, 1954, E.E. Chamberlain.

Hymenophore perennial, stratose, adnate, membranous-coriaceous, at first effused, forming small areas to 6 x 2 cm., becoming deeply areolately angularly fissured when each segment becomes separated, each appearing as a separate colony irregular in shape and 2-10 mm. long; surface white, becoming pallid cream, deeply creviced; margin at first thin, white, crustose, becoming thick and cliff-like. Context white, 0.7-2 mm. thick, arranged in 20-30 vague layers delimited by tinted zones of collapsed parallel hyphae, fertile layer of mainly vertical hyphae widely spaced with collapsed partly pseudoparenchymatous hyphae between; other layers of collapsed hyphae arranged into a coarsely cellular pseudoparenchyma; generative hyphae 2.5-3 µ diameter, wall 0.25 µ thick, naked, hyaline, branched, septate, with clamp connections. Hymenial layer to 35 µ deep, of basidia, paraphyses and paraphysate hyphae. Basidia subclavate, 12-18 x 6-8 µ, 4-spored; sterigmata slender, to 6 µ long. Paraphyses scanty, subclavate, about half the size of the basidia. Paraphysate hyphae filiform, projecting, with rounded or acuminate apices. Spores elliptical or suballantoid, 7-9 x 4-4.5 µ, wall smooth, hyaline, 0.2 µ thick.

DISTRIBUTION. New Zealand.

HABITAT. Adnate on much decayed decorticated wood.

Hymenophorum membranaceo-coriaceum, adnatum, stratosum; coloniis inaequaliter crebris, 2-10 mm. longis; superficie alba deinde pallide cremea, alte rimosa. Contextus 20-30 stratis zonis tinctis collapsorum textuum. Hyphae fibulatae, 2.5-3 µ diam., nudae. Basidia 12-18 x 6-8 µ, 4 sporis. Hyphae paraphysatae adsunt. Sporae ellipticae vel suballantoides, 7-9 x 4-4.5 µ,laeves, hyalinae.

Readily recognised by the numerous small, tuberculate, white colonies crowded on rotten decorticated wood. They arise from fructifications which at first are plane and continuous. Soon these become deeply fissured, each segment continuing to develop as a separate entity, the plant being perennial, edges becoming rounded somewhat, though still retaining their vertical faces. Sections show thick specimens to consist of 20-30 rather vague layers, all save the fertile layer being composed of collapsed gelatinized hyphae arranged into a coarsely cellular pseudoparenchyma, separated by bands of parallel gelatinized collapsed hyphae tinted brown. The species appears to be confined to the one host, Agathis australis, the Maori name for which is kauri, hence the specific epithet.

Huia, July, 1947, J.M. Dingley, type collection, P.D.D. herbarium, No. 5568

The type specimen shows collapsed hyphae, no hymenial structures and non-amyloid basidiospores as described by Cunningham. More material is needed before a more definite statement on its taxonomic position can be made. The species causes a brown rot.