 In Hibbett and colleagues ' 1997 publication , Protomycena was placed in the subfamily <unk> , which at the time was considered part of the <unk> family ; Mycena is currently classified in the <unk> family . The placement was based solely on the visible structures , or <unk> of the fruit body . Many of the features which are typically used to classify species into fungal families and subfamilies are based on microscopic features not visible or preserved in the amber specimen . Consequently , the assignment to Mycena is provisional ( the authors also note certain similarities with extant members of <unk> ) , and the describing authors leave open the option of treating the genus placement as <unk> sedis ( uncertain placement ) within the Agaricales . Protomycena is distinct from other amber @-@ preserved mushroom taxa such as <unk> , in the grooved surface of its pileus and its <unk> gills . 
