Pileus 2-6 mm latus, hemisphaericus vel convexus, papilla obtusa vel nulla instructus, subplicatus, minute fibrillosus, pallide rubrobrunneus, ad discum obscurior. Lamellae subliberae vel adnexae, subdistantes, albae dein cremeae pallide roseae tinctae. Stipes 15-30 x 0.3-0.5 mm, aequalis, cylindricus, glaber, cartilagineus, insiticius, ochraceoaurantius, rhizomorphis luteis nonnullisque instructus. Basidiosporae (5.5-)6.0-7.5 x (2.5-)3.0-3.5 µm, anguste ellipsoideae, leves, hyalinae, inamyloideae. Basidia 20-26 x 4-6 µm, 4-spora. Cheilocystidia (15)20-40 x 8-10(-25) µm, clavata, hyalinia, diverticulis 2-6 x 1-2 µm longis, cylindraceis irregularibusque et membrana ad apicem subincrassata instructa. Pleurocystidia nulla. Pileipellis subhymeniformis ex cellulis clavatis vel irregulariter lobatis, 15-25 x 6-20 µm, membrana luteobrunnea et tenuitunicata instructa, diverticulis numerosis, 2-7 x 2 µm longis, cylindraceis vel irregularibus instructus. Trama pilei subdextrinoidea. Fibulae praesentes. Solitarius ad foliis putridis Nothofagi fuscae. Nova Zelandia. Holotypus: Horak 68-33 (PDD).

Marasmius aurantiobasalis var. aurantiobasalis is currently known only from New Zealand. A further accounting of the variety is presented in Part 2 of this series on South Pacific marasmioid fungi. As with the type variety (known only from New Zealand), var. hispidipes is easily recognized by the reddish brown pileus contrasting with a yellowish orange stipe, relatively narrow basidiospores, and growth on leaves of broad-leaved trees. Marasmius aurantiobasalis var. hispidipes differs from var. aurantiobasalis only in forming a hispidulous stipe covered with lanceolate, acute caulocystidia. The species is most closely allied with M. straminipes var. fibulatus Desjardin & Petersen, described from material collected on oak leaves in southeastern United States. The latter species differs from M. aurantiobasalis in forming a cream-colored to greyish brown pileus, slightly longer (6.5-10 µm) and broader (3.2-4.5 µm) basidiospores, and more irregularly shaped and narrower cheilocystidia (compare with #28 below; Desjardin & Petersen, 1989).