MYRTACEAE. Eucalyptus regnans: Victoria, Tarra Valley Park. South Australia, Mt. Lofty.

Hymenophore perennial, cretaceous, adherent, effused forming irregular areas to 30 x 20 cm, to 2 cm thick. Hymenial surface at first apricot or orange, becoming black and shining, creviced when old; margin at first orange, fibrillose, thinning out, becoming abrupt, often cliff like, inturned, free or adherent. Pores in one or several obscure layers, round, 4-5 per mm, 120-160 µm diameter, to 5 mm in each layer; dissepiments equal, 75-120 µm thick, even, embedded in mucilage. Context (of dried specimens) almost black, like charcoal, fragile, to 1 mm thick, of closely intertwined hyphae cemented with mucilage; generative hyphae 3.5-4 µm diameter, walls 0.1 µm thick, hyaline, septate, branched, with clamp connections. Hymenial layer to 15 µm deep, a close palisade of basidia and spores. Basidia subclavate, 18-24 x 4-4.5 µm, bearing 4 spores; sterigmata slightly arcuate, to 6 µm long. Paraphyses subclavate, or subcylindrical, 14-20 x 3-3.5 µm. Spores broadly elliptical or obovate, apiculate, 3.5-5.5 x 3-4.5 µm, walls smooth, hyaline, 0.2 µm thick, staining.

DISTRIBUTION: North America, Australia.

HABITAT: Bark and decorticated wood of fallen trunks, associated with a white rot.

The description of basidia and spores has been drawn from North American specimens kindly forwarded by Prof. J. L. Lowe. Mature fructifications are so impregnated with mucilaginous matter that when dried they appear black, firm, and brittle like pieces of charcoal. In the absence of spores and basidia the species may be recognised by this feature. For additional host range, and probable host range, see Walters (1958, p. 96).

TYPE LOCALITY: Selkirk, New York.