This Marasmius of sect. Sicci ser. Leonini has, on occasion, been exceedingly common in Costa Rican oak forests. We have found it in the Talamancas as well as in the volcanic cordilleras (Poas for example). The cespitose cluster seems diagnostic, as well as the glabrous stipe, subrugulose pileus, and crowded lamellae. The epithet "tropalis" refers to the cespitose/clustered habit. It seems closest to M. corrugatus var. aurantiacus described from oak bark in Florida.