Note: Dilophus J. Agardh (1882: 106) was originally distinguished from Dictyota Lamouroux (1809a: 38) by the character of a medulla composed of cells arranged in more than one layer. Numerous workers (e.g., Womersley, 1987: 200) have encountered such variability in this feature as to cast doubt on its utility. Hörnig et al. (1992: 45, 53), in a study focusing on the circumscription of Dictyota, were unable to find any characters that would reliably separate the two genera. In some species the medulla was found to be consistently monostromatic in all parts of the thallus, both in nature and in culture. In other species the medulla was consistently polystromatic. In many species, however, both situations could be found, depending upon the part of the thallus and growth conditions. In this catalogue we include Dilophus in Dictyota.
Dictyota acuminata Kützing, 1849: 555 (type locality: "ad Kosseir'' [Quseir], Egypt).—G. Murray, 1887: 35.— S. Dixit, 1970: 112.
INDIAN OCEAN DISTRIBUTION: Sri Lanka.