Life Cycle and Morphology of Bryopsidella ostreobiformis spec. nov. (Bryopsidaceae,Chlorophyta) from the Mediterranean,under Culture Conditions,with Comments on the Phylogeny of the Bryopsis/Derbesia Complex

Bryopsidella ostreobiformis sp. nov. is presented as the second species of the genus. The latter is amended to accomodate this new species. The derbesioid sporophyte is capable of producing three- to eight-rayed stellate propagules. The dioecious gametophyte is a heterotrichous thallus with branched, prostrate filaments and unbranched, erect ones, and does not resemble Bryopsis. The life cycle is distinctly diplohaplontic, with a diploid sporophyte and a haploid gametophyte. B. ostreobiformis is postulated as the starting point of a hypothetical evolutionary sequence of life histories in the Derbesia/Bryopsis complex.