Beilschmiedia tawa (A. Cunn.) Hook. f. & Benth. Auckland: Lake Rotoehu, 1,200 ft., May, 1952, G.H.C., type collection, P.D.D. herbarium, No. 11475; same locality, December, 1953, G.H.C.

Hymenophore annual or biennial, adnate, membranous, effused, forming irregular linear areas to 18 x 3 cm.; surface seal-brown, even, not creviced; margin thinning out, adnate, byssoid, pallid greyish-brown. Context mouse-brown, 200-450 µ thick, composed of 1-5 obscure zones, each consisting of a basal layer of a few parallel hyphae and an intermediate layer of mainly vertical hyphae partly cemented and collapsed when old, embedded in masses of brown mucilage; generative hyphae irregular, often inflated between septa, 4-6 µ diameter, wall 0.2 µ thick, naked, hyaline (a few tinted near the base), branched, septate, with large clamp connections. Hymenial layer irregular, of basidia and paraphyses. Basidia clavate, 20-36 x 6-9 µ, 2-4-spored; sterigmata stout, to 12 x 4 µ, often inserted laterally. Paraphyses cylindrical with rounded ends, narrower than the basidia. Spores commonly pyriform, some pip-shaped or subglobose, 6.5-9 x 6.5-7 µ, apiculate, wall smooth, hyaline, 0.5 µ thick.

DISTRIBUTION. New Zealand.

HABITAT. Effused on decorticated decaying wood.

Hymenophorum membranaceum, adnatum, effusum; superficie colore phocae, non rimosa. Hyphae contextus 1-5 obscuris parallelis zonis brunneae mucilaginis, fibulatae, 4-6 µ diam.. inter septas inflatae, nudae. Basidia 20-36 x 6-9 µ, 2-4 sporis. Sporae pyriformes vel obovatae attenuato-apiculatae, 6.5-9 x 6.5-7 µ, laeves, hyalinae.

Although surface and context are brown, context hyphae are hyaline, colour being produced by masses of fuscous mucilage which lie between hyphae and upon them at intervals, forming coloured zones which are conspicuous in sections.
The species is somewhat primitive; for the hymenial layer is composed not of a dense palisade, but of scattered basidia and paraphyses arising from different levels of the context. Paraphyses often develop at a wide angle, and may also be seen scattered through the context. Sterigmata are stout, and often inserted almost laterally. Spores do not appear until sterigmata are about three-quarters their full length. Spores are copiously developed, and occur scattered through the context.
The other brown species, C. singulare, differs in that hyphae are coloured brown, spores are smaller and elliptical, and clamp connections are extremely rare.

Auckland: Lake Rotoehu, 1,200 ft., May, 1952, G.H.C., type collection, P.D.D. herbarium, No. 11475

The type specimen is identical with Scotomyces subviolaceus (Peck) Jülich. The generic names Scotomyces Julich (Julich 1978) and Hydrabasidium Parker-Rhodes ex J. Erikss. & Ryv. (Eriksson & Ryvarden 1978) were both published on the same date, 28 Dec. 1978. Thus the first author who made a choice between these genera has to be followed; this is Jülich (1979), who treated Hydrabasidium as a synonym of Scotomyces.