Pileus 2-7 mm diam., at first convex, soon becoming plane or depressed at centre with up turned margin, white, cream or pale yellow, pruinose to velvety (minutely hairy-strigose under hand-lens), indistinctly sulcate towards margin, gelatinous in fresh condition (pileipellis separable). Lamellae 2-6, venose to fold-like, attached to apex of stipe, occasionally hymenophore smooth, cream, edges concolorous. Stipe 3-7 X up to I mm, always central, cylindric, equal, whitish to cream, minutely pruinose overall, dry, solid, solitary in groups, insititious (basal disc or byssus absent). Basidiospores 16-19 X 8-9.5 µm, broadly elliptic, slightly inequilateral in profile, smooth, hyaline, inamyloid. Basidia 40-45 X 11-15 µm, tetrasporic, subcylindric to clavate, sterigmata up to 9 µm long, clamped. Cheilo- and pleuro-cystidia numerous, 60-115 X 20-30 µm, fusiform to lageniform, apex rounded or indistinctly capitate, thin-walled, smooth, hyaline. Pileipellis hymeniform, composed of vesiculose to clavate smooth cells 20-30 X 10-20 µm, subgelatinous, hyaline, thin-walled. Pilocystidia numerous, 40-85 X 8-12 µm, fusiform with long, gradually tapering neck, apex rounded or sub acute, thin-walled, hyaline. Oleiferous hyphae absent. Stipe tissue monomitic. Stipe cortical hyphae cylindric, 5-10 pm diam., smooth, thin-walled. Caulocystidia numerous. 20-110 X 3-7 µm, trichiform or subfusiform with gradually tapering apex, tips rounded or pointed, thin-walled, hyaline.

On rotting leaves of Phormium tenax J.R. & G. Forst. (Phormiaceae). Known from South Island of New Zealand.

Pileus 2-7 mm latus plano-convexus dein depressus, albus vel pallide stramineus, minute pruinosus, subgelatinosus. Lamellae nonnullae (2-6), venosae, rariter desunt, pallide stramineae. Stipes 3-7 X up to 1 mm, centralis, cylindricus, pileo concolor, minute pruinosus. Inodorus. Basidiosporae 16-19 X 8-9.5 µm, ellipticae, leves, hyalinae, inamyloideae. Basidia 40-45 X 11-15 µm. tetrasporica, fibulata. Cheilo- et pleuro-cystidia 60-115 X 20-30 µm, fusiformia, subcapitata, tenuitunicata, hyalina. Pileipellis hymeniformis e cellulis vesiculoso-clavatis (20-30 X 10-20 µm). Pilocystidia numerosa, 40-85 X 8-12 µm, fusiformia, apicaliter attenuata, tenuitunicata, hyalina. Caulocystidia 20-110 X 3-7 µm, trichiformia vel subfusiformia. Ad folia putrida Phormii tenacis. Novazelandiae. PDD, holotypus

Gloiocephala phormiorum belongs in sect. Gloiocephala subsect. Macrosporae Singer (1976) where its closest ally appears to be G. longispenna Singer (from Brazil: Singer 1976). The New Zealand taxon is distinguished by relatively large basidiomes with 2-6 fold-like lamellae and a well-developed, white, central stipe: broad basidiospores (8-9.5 µm diam.); fusiform to lageniform, thin-walled hymenial cystidia 60-110 µm long, and fusiform-rostrate pilocystidia 40-85 µm long. In comparison, G. longisperma forms small basidiomes with a more reduced hymenophore and black stipe base, narrower basidiospores (3-4 µm), ventricose hymenial cystidia 30-40 µm long, and pilocystidia 100-200 µm long (fide Singer 1976). The present new species differs from others in the subsection by lacking metuloid hymenial cystidia, having much larger basidiospores, and in its fructification on Phormiaceae.

Holotype
New Zealand, Canterbury, Ashley, Mt Grey, Kowai River Reserve, 22.ix.1967, Horak (PDD; ZT 67-127, isotype).