Fruit bodies up to 100 x 2 mm, filiform, simple clubs, linear, equal, arising from small white mycelial patches, with no sclerotium. Stipe somewhat narrower than club, appearing silky to glabrous, more or less concolourous with club. Club terete, tan to cinnamon-tan ("tawny-olive", "clay-color", "cinnamon-buff"); surface mat; apex rounded. Taste and odour not recorded.

Tramal hyphae of club 2-25 gm diam., hyaline, thin-to somewhat thick-walled (wall up to 0.7 j.m thick), rarely clamped, strictly parallel, moderately dextrinoid, perhaps adherent. Subhymenium rudimentary. Hymenium thickening; basidia (Fig. 69) 45-60 x 7-8.5 gm, clavate-truncate, sometimes clamped, free in young hymenium, somewhat adherent in older hymenia; contents homogeneous; sterigmata 4, stout, divergent, somewhat swollen proximally, very delicate distally. Cystidioid elements (Fig. 70) 45-60 x 5-6 gm, cigar-shaped, usually constricted about 10-20 gm from apex to appear urniform, thin-walled; contents homogeneous. Caulocystidia (Fig. 71) arising as skeletalised, somewhat inflated tips of superficial stipe hyphae, subsequently elongating into seta-like extensions up to 300 gm long, skeletalised at base (wall up to 2.2 gm thick), progressively thinner-walled distally, finally thin-walled at tip, lanceolate to stiff-filiform, more numerous downward, subpilose at stipe base.

Spores (Fig. 72) 6.5-9 x 4.3-5.0 gm (E =1.54-1.92; E^' = 1.70; L'" = 7.86 gm), broadly cylindrical, somewhat flattened adaxially, smooth, thin-walled, hyaline; contents homogeneous, or apparently univacuolate; hilar appendix small, papillate.

North Temperate Macrotyphula junceus (Fr.) Berthier, extremely similar to this taxon, shows clamps on hyphae of all tissues. In M. defibulata, clamps vary from rare to absent. For example, TENN no. 43409 showed rare clamps on tramal and subhymenial hyphae, whereas only two basidial bases were observed as clamped (although the hymenium was agglutinated and so made accurate observation difficult). Conversely, TENN no. 43408 showed no clamps, even though subhymenium and basidia were easily observed. Moreover, when tramal clamps are present, they seem to be occasionally local, but absent from most septa. Thus, in both forms of M. defibulata clamps are rare to absent. Examination of a specimen of M. junceus from Europe (TENN no. 41316, Brienz, Switzerland) confirmed that most (if not all) tramal septa were clamped.

To form a better judgment of variation within Macrotyphula junceus, I examined several additional specimens under that name with the following results. 1. India (TENN no. 37687, Tiger Hill, ex PAN 237): fruit body apparently brown; basal patch dark brown; tramal hyphae thick-walled, yellowish, unclamped, disarticulating commonly; spores 5.8-7.2 x 4.3-5.4 gm (E"' =1.32). Probably an undescribed taxon. 2. Eastern North America (TENN no. 40118, Great Smoky Mountains National Park): fruit bodies tan, very stout (up to 2.5 mm thick); basal pad white; tramal hyphae less inflated than in other specimens, thin-walled, clamped; subhymenium and hymenium free; basidia 45-55 x 6-7 gm, narrowly clavate, clamped; spores 7.6-9.7 x 4-4.3 prrt (E'" = 2.11). Probably an undescribed taxon. 3. Western North America (TENN no. 34409, Redwood Forest, California): fruit bodies and micromorphology indistinguishable from European material. 4. South-eastern Australia (TENN no. 41222, Brisbane Ranges): fruit bodies and micromorphology indistinguishable from M. defibulata f. defibulata.

The best summary of this genus, originally monotypic (Petersen 1972), was by Berthier (1976) in which he accepted four species. The only taxon producing filiform fruit bodies was Macrotyphula lunceus, which, faithful to Corner (1950, 1970), was reported virtually worldwide. Even the very crude summary above indicates that additional taxa await description, but that characters will not be easily observed.

Berthier (1976) reported that European material of Macrotyphula junceus was heterothallic and tetrapolar. Spores of New Zealand material easily germinate and can be tested in the same way. Care must be taken to ascertain that spores are uninucleate, as they are in M. junceus.

Within a few millimetres of the fruit body apex, the hymenium is free, and basidia squash so their bases are relatively easily seen. Older portions of the hymenium and subhymenium become adherent to agglutinated, however, and hyphal details become almost impossible to observe.

The typical form apparently fruits on broad-leafed debris. Another form, with much paler fruit body colour, fruits predominantly on Dacrydium debris. Because this colour difference may be a micro-ecological phenomenon, I propose only a form to accommodate it, especially because this seems to be the only difference.