Acoraceae was long thought to be part of the Araceae family. Grayum (1987) already provided evidence and arguments supporting its removal and molecular phylogenetic research (APG III 2009) demonstrated that both appear to belong to different orders, Acorales and Alismatales respectively.
The family includes a single genus, Acorus.
APG III (2009) An update of the Angiosperm Phylogeny Group classification for the orders and families of flowering plants. APG III. Bot. J. Linn. Soc. 161(2): 105-121. [available online at: http://reflora.jbrj.gov.br/downloads/APG1.pdf]
Grayum M.H. (1987) A summary of evidence and arguments supporting the removal of Acorus from the Araceae. Taxon 36: 723-729.
Thompson S.A. (1995) Systematics and Biology of the Araceae and Acoraceae of Temperate North America. Ph.D. dissertation. University of Illinois. Urbana-Champaign.