This has to be one of the loveliest species of Marasmius  in the world (and not just
because I described it!).  Populations can number in the hundreds of basidiomata.  The
species is closely allied with the pantropical taxon, M. ferrugineus  Berk. & Curtis in
sect. Sicci , ser. Haematocephali , and was most likely introduced to the Hawaiian
Islands along with plants or animals from the New World.  For a comparison with
allied taxa see Canad. J. Bot. 70: 530-542, 1992.