Pi1eus 6-14 mm diam, hemispherical to convex when young, expanding with age to plano-convex with a flat or subdepressed disc; margin decurved, plicate; surface dull, dry, glabrous; beige to pale reddish brown with a fuscous disc. Texture tough, membranaceous; context thin.- Lamellae adnate, subdistant (11-13) with 2-series of lamellulae, often anastomosing, moderately broad (up to 2 mm), beige; edges even, concolorous.- Stipe12-25 x 0.4-0.7 mm, central, equal or gradually tapering towards the base, often twisted, wiry, glabrous when dry, in wet condition covered with a thick, hyaline, gelatinous coat, insititious; white to beige at the apex, black elsewhere; rhizomorphs absent.- Odor and taste not distinctive.
Basidiospores 6-8 x 3-3.5 µm, narrowly ellipsoid, smooth, thin-walled, hyaline, inamyloid.- Basidia 25-32 x 5-6 µm, cylindrical to subclavate, 4-spored, clamped.- Basidio1es 25-35 x 5-6 µm, fusoid, thin-walled, hyaline.- Cheilocystidia absent.- Pleurocystidia absent.Pileipellis a Rameales-structure with suberect to erect, diverticulate terminal cells, 10-25 x 4-10 µm , irregularly cylindrical, often lobed, hyaline; diverticula 2-3 x 0.5-1.0 µm , irregularly cylindrical, hyaline; subcutis composed of interwoven, cylindrical hyphae with brown incrusting pigment.- Pileal and lamellar t rama tissues inamyloid.-Stipe tissues monomitic; cortical hyphae roughened, thick-walled, gelatinous, dark brown, dextrinoid; medullary hyphae weakly hyaline, dextrinoid.- Cau1ocystidia absent. - Clamp connections present.

Habit, habitat and distribution.- Solitary or cespitose on rotten bark and leaves of Nothofagus menziesii (Fagaceae). New Zealand.

Pileus 6-14 mm, convexus vel planus et disco subdepresso instructus, plicatus, glaber, ex argillaceo pallide castaneus vel fuscus. Lamellae adnatae, subdistantes, frequenter anastomosantes. Stipes 12-25 x 0.4-0.7 mm, centralis, cylindricus, gelatinoviscidus m statu humido solo, mox siccus, glaber, insititius, apicaliter ex albo argillaceus sursum niger, rhizomorpha nulla. Odor saporque nulli. Basidiosporae 6-8 x 3-3.5 µm, anguste ellipsoideae, leves, hyalinae, inamyloideae. Basidia 25-32 x 5-6 µm , 4-spora. Cheilocystidia et pleurocystidia nulla. Pileipellis typi Ramealium, ex cellulis diverticulatis, 10-25 x 4-10 µm, saepe lobatis, membrana hyalina, diverticulis 2-3 x 0.5-1.0 µm instructa, hyphae subcuticulares pigmento brunneo incrustatae. Trama pilei et lamellarum inamyloideum. Hyphae stipitis corticales gelatinosae, fuscae, dextrinoideae. Caulocystidia nulla. Fibulae praesentes. Solitarius vel caespitosus, ad corticem et folia putrida Nothofagi menziesii. Nova Zelandia. Horak 69-217 (Holotypus, PDD).

As the epithet implies, the most unusual feature of M. gelatinosipes is a strongly gelatinous stipe surface when wet and corresponding gelatinous stipe cortical hyphae. The absence of cheilocystidia is also unusual although not unique to this species. Overlooking these two taxonomically important features, M. gelatinosipes is similar to M. pilgerodendri Singer, another species that sporulates on leaves of Nothofagus. Marasmius pilgerodendri, described from Argentina, differs in forming a paler pileus, non-gelatinous stipe, and forms diverticulate cheilocystidia.

Material examined. - NEW ZEALAND: South Island, Prov. Fjordland, Milford Sound, near Homer Tunnel, 1 IV 1969, Horak 69-217 (Holotype, PDD; Isotype, SFSU, ZT).