Studies on the development, life history and taxonomy of the Ectocarpales (Phaeophyta) in southern Australia

Abstract

The morphology, development and life history of filamentous brown algae, in particular species of the commoner genera Feldmannia, Giffordia and Hecatonema, are described. Morphogenetic differences parallel the well known morphological distinctions between Feldmannia and Giffordia. Two 'species' of Feldmannia, F. globifer and F. simplex, are not distinct but rather exhibit continous variation of a clinal nature. Previous records of Giffordia secunda are shown to apply to Giffordia granulosa. Studies of living and type material of Ectocarpus sordidus indicate that its affinities lie with the genus Giffordia, to which it is transferred. Life histories of the various ectocarpalean taxa show many similarities and, with minor exceptions do not furnish additional useful taxonomic characters. The predominant means of reproduction amongst the Australian Ectocarpales are asexual, sexual processes being apparently of minor signi- ficance. Life history studies of Hecatonema maculans show it to be indistinct from juvenile stages of two members of the Dictyosiphonales, Desmotrichum undulatum and Punctaria latifolia. Five genera and six species are newly recorded for Australia. The genera are Acinetospoua, Hecatonenza, Kuckuckia, Kuetzingiella and Sovocarpus and the species are Acinetospora crinita (Carmichael ex Harvey in J. D. Hooker) Kornmann, Giffordia fuscata (Zanardini) Kornmann in Kuckuck, Giffordia intermedia (Rosenvinge) Lund, Hecatonema maculans (Collins) Sauvageau, Kuckuckia spinosa (Kiitzing) Kuckuck and Sorocarpus micromorus (Bory) Silva.