On dead (1) Dysoxylon spectabile, Auckland, Titirangi, 24.X.1966, 6.I.l967, R. F. R. McN., 25368, 25595; (2) Leptospermum ericoides, Henderson Valley, Sharp's Bush, 20.II.1966, R. F. R. McN., 25024: Titirangi, 11.XII.l966, R. F. R. and R. J. McN., 25514; 3.III.l966, 11.XII.l966, 6.I.l967, R. F. R. McN., 25042, 25525, 25596; Auckland Domain, 7.III.l966, R. F. R. McN., 25060; (3) L. scoparium, Waitakere Dam, 9.II.l966, R. F. R. McN., 24992; (4) Nothofagus fusca Nelson, Maruia, 23.III.l966, R. F. R. McN., 25294; (5) unknown hosts, Anawhata, Titirangi, 30.XI.l966, 7.II.l967, R. F. R. McN., 25449, 25621.

Fructifications soft-waxy to fleshy, resupinate, thin, effused, indeterminate, often tuberculate, forming linear areas to 15cm long, pruinose, greyish-white to greyish-cream when fresh, drying to a pallid grey, pruinose, reticulate or occasionally crustose film; margins concolorous, adnate. In section 50-90 ^ thick, consisting of basal layer and hymenium. Basal layer to 20 p. thick, composed of indistinct, gelatinised, agglutinated, hyaline hyphae, clamp connections present. Hymenium composed of gloeocystidia and basidia, dikaryophyses absent; gloeocystidia abundant, cylindrical, subfusiform or subclavate, occasionally with globose heads to 13 µm diam., arising from basal hyphae or base of fertile hyphae, at first hyaline, contents becoming pallid yellow, granular, 20-38.5 x 4.5-8 µm; probasidia obovate to pyriform, with basal clamp connections, formed in terminal groups on erect, fertile hyphae, 11-14.5-(17) x 6.5-10 µm becoming 2-celled by longitudinal septa or longitudinally cruciate-septate; sterigmata subulate, 5-10.5 µm long; old basidia collapsing, forming an involucre around axis of fertile hyphae. Basidiospores globose to subglobose, hyaline, prominently and symmetrically apiculate, smooth to finely roughened or echinulate, 5.8-8.5-(10) µm diam. Germination not observed.

Dead angiosperm and gymnosperm wood.

Wells, Mycologia 51: 554, fig. 5. 1959; Luck-Alien, Can. J. Bot. 41: 1035, fig. 10-15. 1963.

The presence of gloeocystidia with yellowish-brown, granular contents indicates that Sebacina caesio-cinerea belongs in sect. Bourdotia. Opinions are almost equally divided as to whether Bourdotia merits sectional or generic status. In a comprehensive study of Bourdotia, Wells (1959) accorded it generic rank and recognised 11 species. The genus was distinguished by the presence of gloeocystidia with yellow or brownish granular contents, method of basidium formation, and structure of the fructification; three characters previously employed by Rogers (1933) to define Bourdotia as a subgenus of Sebacina. More recently, Luck-Alien (1963) considered Well's interpretation of Bourdotia too broadly based and divided the genus further. The gelatinous members such as Sebacina galzinii Bres., the type species of Bourdotia, were placed in Exidiopsis subg. Bourdotia. while arid-waxy species were transferred to Basidiodendron Rick. At the same time, two new subgenera of Basidiodendron were recognised. Sebacina caesio-cinerea was placed in the type subgenus by Luck-Alien.
Considerable variation occurs in the degree of roughening of spore walls in S. caesio-cinerea Bourdot and Galzin (1928) erected a variety of Bourdotia cinerella Bourd. & Galz„ a species now considered a synonym of Sebacina caesio-cinerea to accommodate specimens with roughened or angular spores. Var. trachyspora does not appear to have been validly transferred to S. caesio-cinerea although the combination Bourdotia caesio-cinerea var. trachyspora was used by Oberwinkler (1963). Both smooth and roughened spores can often be found in the same fructification and it seems unnecessary to recognise var. trachyspora.
Sebacina caesio-cinerea is characterised by the prominently apiculate and often finely roughened subglobose to globose spores, abundant gloeocystidia, and basidia with short, subulate sterigmata. In older fructifications, collapsed basidia forming an involucre around the erect fertile hyphae are a distinctive feature. The species is widely distributed throughout the Northern Hemisphere and has not previously been recorded from New Zealand.

Lengerich, West Germany.