Vulcanodinium rugosum gen. nov., sp. nov. (Dinophyceae): a new marine dinoflagellate from the French Mediterranean coast. A new armoured marine dinoflagellate, Vulcanodinium rugosum Nézan et Chomérat, gen. nov., sp. nov. is described from water samples of Mediterranean lagoons. The thecal plate formula is Po, X, 4′, 3a, 7″, 6c, 6s, 5′″, 2″″. The apical pore plate Po is very large and a mucous matrix is extruded from its centre. The plate X is rather long and just below is the narrow and short first apical plate 1′. The intercalary anterior plates are contiguous. The first cingular c1 plate is narrow. The number, the shape of plates and the presence of lists characterize the sulcus. The thecal surface is covered by longitudinal striae with often cross reticulations and is perfored by large pores. According to the studied feature, the morphology of Vulcanodinium rugosum looks like, either a peridinioid or a gonyaulacoid species. A phylogenetic study, based on LSU rDNA sequence data, confirms that this taxon is new and that it belongs to the order Peridiniales. However, it is not possible to affiliate it neither to a particular family nor to a known genus. As a consequence, a new generic name, Vulcanodinium is proposed with V. rugosum as type species, assigned in the order Peridiniales, incertae sedis for the time being.

A new Peyssonnelia species is described from deep-water habitats in Puerto Rico as well as the U.S. Virgin Islands. Peyssonnelia incomposita is distinctive when living due its background orange coloration with highly contrasting bright yellow highlights. Internally the thallus is distinguished by abundant cell fusions that occur both laterally and longitudinally among cell rows of the perithallus as well as between cells of adjacent perithallial filaments at different tier levels. Tetrasporangia are cut off distally and possess an enlarged pedicel. They measure to 30 µm wide and 75 µm long. The crusts are closely appressed to the substratum and while variable, normally measure approximately 75 µm in thickness.

A new Peyssonnelia species is described from deep-water habitats in Puerto Rico as well as the U.S. Virgin Islands. Peyssonnelia incomposita is distinctive when living due its background orange coloration with highly contrasting bright yellow highlights. Internally the thallus is distinguished by abundant cell fusions that occur both laterally and longitudinally among cell rows of the perithallus as well as between cells of adjacent perithallial filaments at different tier levels. Tetrasporangia are cut off distally and possess an enlarged pedicel. They measure to 30 µm wide and 75 µm long. The crusts are closely appressed to the substratum and while variable, normally measure approximately 75 µm in thickness.

Gonimophyllum buffhamii, a red algal hemiparasite on Acrosorium ciliolatum and Cryptopleura ramosa (Delesseriaceae), is rare along the coasts of the Iberian Peninsula. We describe male gametophytes with spermatangial sori and tetrasporophytic plants for the first time in this area. The species is reported for the first time on A. ciliolatum along the Iberian Peninsula. A comparison is made with the three other species of the genus in order to facilitate their separation.

The red algal genus Caloglossa (Delesseriaceae, Ceramiales) in the New World is represented by Caloglossa leprieurii sensu lato. The earliest name for any species in the genus, other than the basionym Delesseria leprieurii, is Apiarium apiculum. On the basis of comparative morphological data, and rbcL and LSU rDNA sequence analyses, the C. leprieurii complex in the New World is found to include four species: C. leprieurii, C. apomeiotica, C. apicula comb, nov., and C. ruetzleri sp. nov. The four species can be distinguished by subtle vegetative characters, including rhizoid morphology, the degree of constriction at the thallus nodes, presence or absence of adventitious branches, number of cell rows cut off from the first axial cell of the main axis, and the position of the cystocarp on the blades. A dichotomous key highlights the diagnostic vegetative characters to separate species of the C. leprieurii complex that occur in the Americas. Caloglossa leprieurii is a tropical species from the Caribbean Sea, the Indian Ocean and the tropical eastern Pacific Ocean. Caloglossa ruetzleri is apparently restricted to the Caribbean Sea and the Gulf of Mexico, C. apomeiotica to the eastern Pacific and southern Atlantic Oceans, and C. apicula the Western Atlantic Ocean, Gulf of Mexico and Indian Ocean.

Morphological evidence supports the specific status of the endemic Mediterranean red algal taxon Dasya rigescens. Compared to D. ocellata, which is a more widely distributed and less deep species, D. rigescens shows clear morphological differences in cortication cells, pseudolaterals, spermatangial branches, cystocarps and stichidia location. The nomenclature and lectotypification of D. rigescens are discussed, and previous data are reviewed and clarified.

The desmid flora of Serbia has been surveyed during various periods. The first data on the distribution of desmids in Serbia date back to 1883 and from then on until 2009 altogether 630 different taxa were identified. Among 23 genera of desmids in all, the most diverse and most commonly found is Cosmarium (242 taxa or 38.4% of the total number of taxa). Taxa belonging to the genus Cosmarium grow in distinctly diverse habitats, from lowland rivers to high-mountain peat bogs. The present paper gives a survey of the major taxonomic and ecological characteristics of the Cosmarium taxa which have been identified in Serbia. The present studies regarding the distribution of Cosmarium taxa over the territory of Serbia, show that extremely rare, very rare and rare taxa comprise 96.3% of all recorded Cosmarium taxa. The species Cosmarium botrytis, C. laeve, C. meneghinii and C. subprotumidum appear widely distributed in the territory of Serbia. High-mountain peat bogs are characterized by the greatest diversity of the Cosmarium taxa.

This note deals with the taxonomic study and geographic distribution of the genus Kirchneriella Schm. in Argentina, where species and infraspecific taxa have received little attention. The classification of taxa is based on morphological and morphometric characters. Thirteen species and three varieties are recorded, among them K. contorta var. elegans (Playf.) Kom., K. danubiana Hind., K. irregularis var. spiralis Korš. and K. obtusa (Korš.) Kom. are new records for Argentina.