Basicladia emedii sp. nov. is described based on material from six streams in Paraná and Rio Grande do Sul States of Brazil. This is only the second species of Basicladia recorded from South America. The new species is distinguished based on small filaments with short and wide basal cells of upright axes. It is only the second (out of six) species that is only known with an epilithic habit and is not associated with either snail shells or turtle carapaces.

A detailed account of the newly designated neotype specimen of Amphiroa crassa Lamouroux (Corallinales, Rhodophyta) is presented. Reasons necessitating its neotypification with a specimen remote from the reported type locality (Shark Bay, Western Australia) are outlined, and historical background information is provided. Brief comparisons with the recently typified type species of the genus, A. tribulus, and with four other Australian species (A. anceps, A. beauvoisii, A. gracilis, A. klochkovana) whose types have been studied in a modern context also are included. A. crassa differs from all of these species in that intergenicula produce a collar of untransformed, calcified peripheral region cells that surrounds and partly to largely encloses each geniculum.

Stoneworts are a conserved group within green algae which usually inhabit in submerged conditions of slow running and standing water. Charales is a difficult taxonomical group regarding species identification. This paper records 13 species of charophytes within three genera found in about eighty localities from Iran. The taxa Chara connivens, C. contraria, C. crassicaulis, C. fibrosa, C. grovesii, C. gymnophylla (two varieties C. gymnophylla var. gymnophylla and C. gymnophylla var. rohlenae), C. kirghisorum, C. pedunculata, C. socotrensioides, C. tomentosa, C. vulgaris (C. vulgaris var. longibracteata and C. vulgaris var. vulgaris), Nitella hyalina and Tolypella glomerata were studied, including vegetative and oospore characteristics of them. C. vulgaris and C. gymnophylla, are the most common species. The species C. kohrangiana is proposed as a new monoecious species characterized by stipulodes developed in one row, anterior and posterior bract-cells, ecorticate branchlets and diplostichous incomplete axial cortex. C. kohrangiana belongs to subgenus Charopsis section Agardhia subsection Agardhia.

The correct name of the species of Nitella known as the ‘Least Stonewort’ has long been under debate. The problem has now been resolved as Nitella confervacea (Brébisson) A. Braun ex Leonhardi. This taxon, once thought to be an endemic of northwestern France, was neglected for a long time. The basionym Nitella gracilis var. confervacea Brébisson and other taxa connected to this name are typified, and their taxonomic status is assessed.

Identification of dinoflagellates to specific level is sometimes arduous due to high diversity and frequent morphological variability. Focusing on Neoceratium genus, often used as ecological indicator, our collaborative web site provides to scientists an accessible and detailed taxonomic tool, allowing accurate identification of its numerous species and varieties. This original web site offers the possibility to visualize several taxa to avoid confusion between infraspecific taxa of the same species and between morphologically close taxa, belonging to different species.