Leptospermum ericoides A.Rich. Auckland: North-east King Island, Three Kings, December 1955, P.J.Brook. Leptospermum scoparium Forst. Auckland: Orakei Bush, September 1948, D.W.McKenzie. Metrosideros excelsa Sol. ex Gaertn. Auckland: White's Stream, Piha, January 1951, J.M.Dingley, type collection, P.D.D. herbarium, No. 11242; same locality, January 1953, J.M.Dingley. Metrosideros tomentosa A.Rich. Auckland: One Tree Hill, October 1955, S.D.Baker.

Hymenophore resupinate, annual, membranous, adnate, following surfaces of the host closely, at first appearing as numerous irregular colonies 1-3 cm across, merging to form linear areas to 13 x 3 cm. Hymenial surface pallid olivaceous, olivaceous-fuscus, or umber with a yellow tinge, colliculose, finely areolately creviced; margin thinning out, concolorous, delicately fibrillose, adnate. Context ferruginous, 50-80 µ thick, composed of 2-3 overlapping rows of setae embedded in upright hyphae; hyphal system monomitic; generative hyphae 2.5-3 µ diameter, walls 0.25 µ thick, reddish-brown, branched, septate. Setal layer composed of 1-3 overlapping rows of setae arising from the subhymenium and basal zone; setae projecting to 35 µ, subulate, 40-65 x 6-8 µ, walls naked, reddish-brown, lumina narrow. Hymenial layer to 25 µ deep, a close palisade of basidia and paraphyses. Basidia subclavate, 12-16 x 3.5-4 µ, 4-spored; sterigmata slightly arcuate, slender, to 4 µ long. Paraphyses subclavate, slightly shorter and the same diameter as the basidia. Spores suballantoid, apiculate, 4-5 x 1.5-2 µ, walls smooth, hyaline, 0.1 µ thick.

DISTRIBUTION: New Zealand.

HABITAT: Effused on bark of dead branches associated with a pocket rot.

Resupinata, annua, membranacea, adnata. Superficies hymenii pallide olivacea, fusca vel flavide umbrina, colliculosa, rimosa; margine concolori, fibrilloso, adnato. Contextus ferrugineus, 1-3 ordinibus setarum partim superimpositis, hyphis erectis in medio. Hypharum systema monomiticum. Setae subulatae, ad 35 µ eminentes, nudae, 40-65 x 6-8 µ. Basidia subclavata, 12-16 x 3.5-4 µ, 4 sporis suballantoidibus, 4-5 x 1.5-2 µ.

From the other three species of this section H. minuscula may be separated by the colour of the strongly colliculose, minutely creviced hymenial surface, thin context, small setae and spores. The surface to the eye appears pallid olivaceous or yellowish-brown; under a dissecting microscope it appears umber, velutinate with the small setae, and coated with yellow granules. The context is scanty and in old specimens contains masses of crystals, though these are wanting in the type and other well developed specimens. Setae are small, naked, acute and sometimes bear delicate lateral projections 0.5 µ in length. Spores are suballantoid with prominent apiculi. The species resembles H. multisetae Burt in several particulars, differing in the larger setae and differently coloured, strongly colliculose hymenial surface.

Auckland: White's Stream, Piha, January 1951, J.M.Dingley, type collection, P.D.D. herbarium, No. 11242