DICTYOTACEAE, Lamouroux ex Dumortier, 1822

Coppejans, Eric, Leliaert, Frederik, Verbruggen, Heroen, de Clerck, Olivier, Schils, Tom, de Vriese, Thomas & Marie, Daniel, 2004, The marine green and brown algae of Rodrigues (Mauritius, Indian Ocean), Journal of Natural History 38 (23), pp. 2959-3020 : 2999

DICTYOTACEAE Dictyota Lamouroux A recent monographic study of the genus Dictyota in the Indian Ocean ( De Clerck, 2003), based on a morphometric approach, resulted in a reduction of the total number of Dictyota species for that region from 43 to 23, and included the description of two new species. Due to taxonomic confusion and the occurrence of numerous misapplied names ( Coppejans et al., 2001: 404, 408–409) distributional data based on literature reports should be treated with care.

Key to the species from Rodrigues

1 Thalli surface with surface proliferations (sometimes sparse); sporangia surrounded by an involucrum of radially elongated cortical cells; thalli in situ non-iridescent; apical parts sometimes recurved.............. D. cervicornis

– Thalli lacking surface proliferations; sporangia not surrounded by an involucrum; thalli in situ yellowish to blue iridescent; apical parts never recurved..... 2

2 Interdichotomies markedly longer than wide (L/B w 2); apices acute; thalli not closely adherent to the substrate; apices of the same colour as the rest of the thallus D. ceylanica

– Interdichotomies slighty longer than wide (L/B: 1–1.4); apices obtuse to rounded; completely prostrate or forming hemispherical tufts; apices slightly darker than the rest of the thallus.................... 3

3 Thalli prostrate, closely adherent to the substrate, often forming exensive mats on acroporoid corals................. D. friabilis

– Thalli forming hemispherical tufts........... D. bartayresiana