The family consists only of Acorus, a genus of 2-4 species, perennial herbs. Although traditionally treated as part of the Araceae, a wide variety of morphological, anatomical, and embryological evidence supports the segregation of the Acoraceae (Grayum 1987), a segregation additionally supported by molecular studies (Duvall et al. 1993; Chase et al. 1993). The spathe in Acorus is not morphologically equivalent to the spathe of the Araceae.