Although Anthopleura elegantissima is commonly seen in its aggregated or clonal form, another form also exists, larger in size and solitary. Both types sexually produce planula larvae, but the solitary form does not propagate asexually by fission as does the clonal form. Whereas the clonal form occurs more often on the tops of boulders exposed to surf, the solitary form inhabits more protected areas, is usually lower on the shore, and may be partly buried in sand. The solitary form is reported to reach sizes of up to 20cm basal diameter. Although the issue remains controversial, the latest detailed genetic study of the 2 forms now suggests that they are different species. Francis 1979 Am Zool 19: 669; Sebens 1983 Ecol Monogr 53: 405; Smith & Potts 1987 Mar Biol 94: 537; McFadden et al. 1997 Mar Biol 128: 12.