Two Surirella species from China are studied using light and scanning electron microscopy. Surirella wulingensis sp. nov., discovered from Li River (located in Wuling Mountains, China), bears five undulations from pole to pole throughout the whole valve diminution series and parallel valve margins, which differ from other similar taxa. Based on the observations of the fine structure, an amended description is provided for S. tientsinensis which possesses a unique character within the genus Surirella: rounded and rimmed outer openings of areolae. Three new morphological terms are proposed: costa-stria bundle (CSB), over-fibula costa (OFC), and mantle sinking against a fibula (MSAF), which can be used for describing some Surirella taxa more succinctly and explicitly including these taxa in this study.

Psammothidium manguinii is a common constituent of the limnoterrestrial diatom flora of the Antarctic Region. The species shows a broad variability in several morphological and morphometrical features such as valve outline, valve width, striation pattern and length/width ratio. Analysis of the type material of Achnanthes manguinii, described by Hustedt in 1952, and A. manguinii var. elliptica, described by Manguin two years later, together with an analysis of a large number of P. manguinii populations from the sub-Antarctic Region (with samples from all major islands in the southern Atlantic, Indian and Pacific Ocean), resulted in a clear morphological revision of the species. Four new species are described, P. acutomanguinii sp. nov., P. antarcticum sp. nov., P. mannensianum sp. nov. and P. hodgsonii Van de Vijver et Verleyen sp. nov., whereas the former variety elliptica is brought to species level: P. ellipticomanguinii nom. et stat. nov. The morphology, ecology and distribution of all species are discussed and a morphological comparison is made.

Two cyanobacterial strains morphologically identified to the genus Nostoc were isolated from a wet rocky wall in a mid-subtropical region in China, and they were taxonomically and phylogenetically characterized based on the polyphasic approach combining morphological and genetic characteristics. 16S rRNA gene sequence analysis showed that the two strains containing six clones were all >99.6% similar to each other, but had < 94.3% similarities to the existing cyanobacterial genera. The phylogenies based on 16S rRNA and rpoC1 gene sequences indicated that their sequences grouped into a unique and robust cluster with high bootstrap values. This unique cluster was separated from the clade of the 'Nostoc sensu stricto' and the respective clades formed by the morphologically similar genera Mojavia, Desmonostoc, Aliinostoc, Komarekiella and Halotia. The 16S-23S rRNA ITS secondary structure of the both strains exhibited the unique pattern of D1-D1´, Box-B and V3 helix, distinguishing it from the other heterocytous genera. Such a clear cluster leads to the establishment of Minunostoc gen. nov., with the type species as Minunostoc cylindricum sp. nov.

One green algal specimen from China was identified as Gongrosira fluminensis Fritsch, due to its unique morphology that pseudoparenchymal basal stratum with rounded or polygonal cells grew into dense little-branched upright threads that reached approximately the same height with specific akinete formation and germination and formed strong cushions without calcification. Examination of the ultrastructural characteristics of plasmodesmata and pyrenoid confirmed that Gongrosira fluminensis Fritsch should be excluded from the order Chaetophorales. The phylogenetic evidence based on DNA sequence data from the nucleus (18S rDNA, ITS rDNA) and chloroplast (tufA) sequences clearly revealed that the Gongrosira fluminensis Fritsch should be classified in the Ulvales (Ulvophyceae) as the new combination species of the genus Lithotrichon Darienko et Pröschold, instead of the Chaetophorales (Chlorophyceae). More specimens in conjunction with natural morphological investigation and molecular analyses are required to reevaluate the microfilamentous genus Gongrosira Kützing and reveal hidden diversities among the Ulvophyceae.

This study presents the first record of the ochrophyte alga Tetrasporopsis fuscescens in North America, confirmed with light and transmission electron microscopic photomicrographs, cytochemical and molecular phylogenetic analyses. T. fuscescens was recorded rarely, being found in the benthos of only twelve stream sites: nine locations in Southern California and three in Northern California. More than half of the streams were non-perennial, characterized by long dry periods. Tetrasporopsis cells were gold-colored, spherical, with a distinct wall, assembled in the periphery of macroscopical gelatinous colonies, which start as tubular or sac-like structures, but later become membranous. The cells have 1-2 parietal chloroplasts, without a stigma or pyrenoid, and reproduction occurs by longitudinal cell division. Other features of the genus are as follows: cells in the colonies also divide by what appears to be smaller autospores with remnant cell walls remaining, the colonial mucilage consists of cylindrical dichotomously branched tubes radiating from the center of the colony to which attach the peripheral cells, and older cells become filled with large oil droplets. A combined gene tree of sequences from nuclear SSU rDNA, plastid rbcL, psaA, psbA and psbC showed that T. fuscescens specimens from Europe and U. S. A. formed a clade, which clustered with taxa classified in the class Chrysomerophyceae.

Four benthic Anabaena strains isolated from different localities in the Czech Republic were examined from the morphological, phylogenetic, and physiological points of view. The results of combined analysis showed distinct morphological dissimilarity between the studied strains, which were further found to belong to different phylogenetic groups based on the 16S rRNA gene phylogeny. To assess the temperature and light (irradiance) optima of the strains, we exposed them to various combinations of these two parameters. The experiment revealed unexpectedly high temperature and light optima for some of the strains, while others showed optima that were similar to those of previously studied planktic species of related heterocytous genera. Our study is the first of its kind to be applied to benthic Anabaena strains. Our results indicate that the benthic Anabaena genus is much more complex than previously thought and provide novel insights into the biology and ecology of benthic Anabaena species. With the collection of more data, we expect the genus Anabaena will be split into several new monophyletic taxa, each covering distinct morpho- and ecotypes.

The phylogeny of the family Selenastraceae was investigated by light microscopy, 18S rDNA, rbcL and ITS-2 analyses. Various morphological features traditionally used for species and genera identification were investigated. All selenastracean strains studied have naked pyrenoids within the chloroplast, except the genus Chlorolobion, which presented starch envelope. The molecular analyses showed that no morphological criterion considered so far is significant for the systematics of the Selenastraceae, but a set of features may be suitable to identify the genera Ankistrodesmus and Chlorolobion. Phylogenetic analyses showed the genera Monoraphidium, Kirchneriella and Selenastrum were not monophyletic and not distinguishable as separate genera. The polyphyly of the genus Selenastrum led to the description of two new genera, Curvastrum gen. nov and Messastrum gen. nov.

Diatoms are used routinely to assess pollution level in rivers and lakes. Current methods are based on identification by light microscopy, which is laborious. An alternative is to identify species based on short DNA fragments and High-Throughput Sequencing (HTS). However a potential limitation is the incomplete coverage of species in reference barcode libraries. Usually these libraries are compiled by isolating cells, before culturing and sequencing them, which is tedious and often unsuccessful. Here we propose the use of rbcL sequences from environmental samples analysed by HTS. We set several criteria to ensure good sequence quality and correspondence with the target species observed in microscopy: the sequence needed to be abundant in the sample, and with no insertions nor deletions or stop codon, phylogenetic neighbour taxa had to correspond to neighbour taxonomic taxa expected from morphological observations. Four species from tropical rivers are given as examples, including one that is new to science.

Zdeňka Žáková was born 17. 4. 1938 in Brno. Zdeňkas’ love for nature have predestined her life path. After graduation from grammar school she started to study biology and chemistry with specialization in plant physiology at the Faculty of science, Masaryk university (former Jan Evangelista Purkyně university) in Brno. She successfully completed her studies in 1961 obtaining an academic title graduated biologist (promovaný biolog). She continued in plant physiology studies and achieved another two academic degrees: RNDr. (rerum naturalium doctor) in 1967 and CSc. (candidatus scientiarum) in 1977.

Melting snow fields populated by aplanozygotes of the genus Chloromonas (Chlamydomonadales, Chlorophyta) are found in polar and alpine habitats. In the High Tatra Mountains (Slovakia), cells causing blooms of brownish-red snow designated as Scotiella tatrae Kol turned out to be genetically (18S, ITS1 and ITS2 rDNA, rbcL) very closely related to Chloromonas nivalis (Chodat) Hoham et Mullet from the Austrian Alps. Therefore, Sc. tatrae is transferred into the latter taxon and reduced to a subspecies as Cr. nivalis subsp. tatrae. Both exhibit a similar photosynthetic performance, thrive in similar habitats at open sites above timberline, but differ in astaxanthin accumulation and number of aplanozygote cell wall flanges. In a field sample of Cr. nivalis subsp. tatrae, polyunsaturated fatty acids formed nearly 50 % of total lipids, dominating in phospholipids and glycolipids. Cr. nivalis subsp. tatrae represents likely a variation of a common cryoflora species with distinct morphology.

Members of Quadricoccus-like algae are characterized by oval to ellipsoid cells adherent to the bowl-shaped or stretched, empty mother cell walls and are common in phytoplankton of inland waters. To date, the morphologically similar genera Quadricoccus and Lobocystis are accepted for this group and the former had been phylogenetic positioned in Oocystaceae. In this study, seven strains of Quadricoccus-like algae were identified and successfully cultured in the laboratory. Light and electron microscope observations and phylogenetic analysis revealed that the strains represent three different species within a new genus, described here as Quadricoccopsis gen. nov. It differed from genus Quadricoccus by characteristically cell adherent mode that two pairs of daughter cells connected to the mother cell remnant respectively by the pole and median portion and distinguished from Lobocystis by variable 2-4-8 autospores, characteristically cell adherent mode and only found in limnetic water. The three new species, described here as Q. simplex, Q. parva and Q. glomerata, differed in cell size, colony morphology and autospore number. Phylogenetic analysis revealed the genus Quadricoccopsis in Oocystaceae and a close relationship with Oocystidium, which is far away from the phylogenetic position of Quadricoccus in one of the granulated clades. The Quadricoccus-like algae were, therefore, proved to be a paraphyly. Furthermore, apart from Planctonema-like algae, the Oocystaceae characteristic cell wall ultrastructure, which is multi-layered with cellulose fibrils in each layer perpendicular to those of the adjoining layer, is not shown again in genus Quadricoccopsis. Different cell wall substructures may be related to the colony formation mechanism. Whether the ultrastructure criterion is applied to all the Oocystaceae needs to be re-evaluated and, further, the definition of this family should be discussed.

Two new freshwater species of Achnanthidium Kützing are described from Eastern Ghats Mountain range of Peninsular India based on light and scanning electron microscopy observations. Achnanthidium initium sp. nov. belongs to the group of Achnanthidium taxa that have terminal raphe fissures curved to opposite sides of the valve. This taxon is characterized by distinctive fascia, raphe endings extending to the valve margin, lineate distal raphe endings and 2-5 linear areola per striae. Achnanthidium linannulum sp. nov. belongs to the group of Achnanthidium taxa with terminal raphe fissures curved to the same side of the valve. This species is characterized by the presence of occluded areolae near the margin, striae orientation and the weakly bent internal distal ends of the raphe. These new species are known only from their type locality, oligotrophic Masilla Waterfalls from Kolli Hills, Eastern Ghats.

Two sympatric species, Delicata sinensis Krammer et Metzeltin and D. williamsii sp. nov. are studied under light and scanning electron microscopy. Both species possess open valvocopulae, which is reported for the first time within the genus. Delicata sinensis often exhibits a semifascia-like central area but sometimes only a little broadened central area bordered by a few shortened striae in the middle part of the dorsal side. Regarding D. williamsii, a freshwater, epilithic taxon, it exhibits a unique combination of characters: a dorsiventral valve outline, non-produced ends and, remarkably, widely spaced 2-3 very long striae in the middle part of the dorsal side. Its status as a distinct species can be confirmed by the presence of 3-4 stigmata on the central area of the ventral side and the undulated striae, more distinctly near the pole. Delicata williamsii is finally compared morphologically with similar Delicata species.

Planothidium juandenovense sp. nov. (Bacillariophyta) is described from the marine tropical environments of Juan de Nova I. (Mozambique Channel), Rodrigues I. (Mascarene Archipelago) and from Guam (Northern Mariana Is., Pacific). This small and relatively rare taxon has short multiseriate striae on the sternum valve (SV), hooked raphe valve (RV) terminal raphe endings and no SV cavum or hoof-shaped area. This taxon has similarities with Planothidium delicatulum (Kütz.) Round et Bukht. and Planothidium septentrionale (Østrup) Round et Bukht. ex Rumrich et al., but also differences: e.g. a relatively narrow and rhombic SV sternum, void of areolae, with vestigial radiate structures and an uninterrupted marginal SV elevated crest or 'crista marginalis'. P. juandenovense sp. nov. is compared to some other Achnanthales with short SV striae. Cocconeis quarnerensis var. lanceolata Jurilj and Planothidium quarnerense f. rhombica (Giffen) comb. nov. may be close to our new taxon.

Galdieria sulphuraria (Cyanidiales) is a worldwide acclaimed thermoacidophilic red microalga with a limited distribution due to special conditions required for growth and metabolism. Until now, the alga was almost exclusively restricted to acid geothermal environments around the world. However, we have found this species on the surface of a burning coal spoil heap in central Europe. It is the first record of G. sulphuraria in this type of habitat. A rbcL phylogeny confirmed that the population of this extremophile belongs to the continental European lineage and we consider Italian geothermal sites as a potential source of Czech G. sulphuraria. The dispersal of unicellular red microalgae is far from fully understood and the discovery of Galdieria in another region of Europe on a relatively newly established anthropogenic site allows us to understand better the distribution patterns and dispersal abilities of this ecologically important algal group. In addition, we have also analyzed the phylogenetic position of Galdieria strain CCALA 965 isolated from a highly acidic site without geothermal activity in the Czech Republic and confirmed it to belong to the species G. phlegrea, until now known only from Italy.

Numerous questionable extant populations of Diploneis with cribrate areolae are morphologically compared (in LM and SEM) to resembling established taxa. In most of these examinations the types are available and documented in the literature by several authors during the last forty years. All taxa in question belong ecologically to the minority of Diploneis that live exclusively in freshwater. As main result twelve species from Europe and one from Florida, U.S.A., are selected and proposed as new to science. These are: D. abscondita, D. calcilacustris, D. hinziae, D. lusatica, D. modicahassiaca, D. oblongellopsis, D. praetermissa, D. puellafallax, D. tirolensis, all from Central Europe (Austria, Germany, Switzerland); D. nanofontanella and D. tundra from European Arctic Russia; and D. parahinziae from Florida. After critical examination, D. arctica stat. nov., D. ladogensis stat. nov., and D. dilatata stat. nov. are proposed to be transferred from infraspecific to species rank.

While collecting epiphytic diatom samples from the west coast of Sweden, a small Mastrogloia species has been observed and could not be matched with any of the described taxa. Based on both light and electron microscopes examination, this species has been described as new, Mastogloia wulffii sp. nov. and included in Mastogloia section Sulcatae. This species is very small with valve length not exceeding 16.3 µm. It is characterized by having a narrow, almost straight median depression on both sides of the sternum-raphe, no marginal ridge and with rounded areolae on valve mantle as well as having completely hyaline lateral sterna. A comparison with similar taxa is given. M. wulffii is a marine species growing in moderate numbers on the red alga Polyides rotunda which is widely distributed along the coast of Vrångö Island, Sweden.

Scrapings from several juvenile Chelonia mydas Linnaeus (green turtle) from Eastern Caribbean and adults from French Guiana allowed for the description of two small and relatively rare epizoic Tursiocola species (Bacillariophyta). Differences with the other eight Tursiocola species previously described are discussed here. Particular attention is given to the cingulum of the two new species and a conceptual key is proposed for Tursiocola species, based on the cingulum structure.

The purpose of this study was to present LM and SEM observations of Nitzschia taxa encountered on the South Shetland Islands and James Ross Island. During the ongoing taxonomical revision of the freshwater and limno-terrestrial diatom flora on the South Shetland Islands and James Ross Island (Maritime Antarctic Region) eight unknown taxa belonging to the genus Nitzschia were found. These taxa were previously force-fitted into European names such as N. commutata or N. perminuta, but detailed light and scanning electron microscopical observations allowed their separation from the already known taxa and resulted in the description of eight new species. The paper discusses all twelve Nitzschia taxa found in the Maritime Antarctic Region. New taxa are compared to the morphologically most similar taxa and their ecology and biogeography are discussed. Although the genus Nitzschia is present worldwide, a large number of Nitzschia taxa have a restricted distribution within the Antarctic Region, showing a clear bioregionalism.

Eunotia is a diatom genus characterized by a short raphe system restricted to both valve poles and by the presence of rimoportulae. As part of a survey examining the genus, Eunotia enigmatica sp. nov. is described from ultra oligo- to oligotrophic and slightly acidic reservoirs in São Paulo State, southeast Brazil. The species is unusual in having a short distinct raphe, and a 'fragilarioid' appearance with long cells and marginal spines. It was commonly found in the planktonic community as well as on sediments of the studied reservoirs. It seems to be adapted to an open water existence, and is similar to E. croatana and E. pseudofragilaria both described from North America. Additionally, type material of another similar looking species, Fragilaria braunii, was analysed using light and scanning electron microscopy and a new combination is proposed for it in the genus Peronia.

Several species currently belonging to the genus Fragilariforma D.M. Williams et Round are known worldwide. This genus is mainly characterized by regular spacing of the uniseriate striae composed of round areolae bearing simple vela, and simple apical pore fields. A large number of species has been recognised for some regions of South America and tropical Africa, but few studies encompass type material and/or the morphological variation existing within populations of the different species. The aim of this study is to identify and describe the morphology of these species from tropical environments under light and scanning electron microscopy and using available type material. Nomenclatural issues are examined and clarified for five taxa: Fragilaria nitzschioides var. brasiliensis Grunow, F. undata var. brasiliensis C. Zimmermann, F. strangulata (Zanon) D.M. Williams et Round, F. telum J.R. Carter et Denny and F. rolandschmidtii Metzeltin et Lange-Bertalot. The type material of F. nitzschioides var. brasiliensis, housed in the Grunow Collection at the Naturhistorisches Museum Wien (W) was examined and its epitypification is proposed. One new species from the Amazon region Fragilariforma amazonica sp. nov. is presented and described here, while Fragilaria telum is formally transferred to the genus Fragilariforma.

Cholnoky described several new Surirella taxa from Africa and we have re-investigated this material. As many other of his contemporary authors, especially in the case of description of new African diatoms, Cholnoky did not indicate holotypes. In the present paper original materials are re-evaluated, lectotypes and a holotype are designated and also epitypes whenever it was appropriate. Taxa later transferred to Stenopterobia have not been taken into account. A short description of the seven species concerned (Surirella anassae, S. chasei, S. coei, S. oliffii, S. ostentata = Surirella ovata var. africana, S. pseudotenuis and S. pseudothienemannii) is given based on the original light microscopic descriptions. Additional morphological information based on scanning electron microscopy is added if available. The presently known ecology and distribution of the taxa is given as are other remarks, based on own observations. For each of the seven taxa Cholnoky's original drawings are presented, which were later re-drawn for publication and which are kept in the archive of the South African National Diatom Collection. The results are discussed referring to the outcome of the digitization project of African Surirellaceae (diatoms, microscopic algae) in the frame of the African Plants Initiative.

There are several places in the world where the level of natural radiation is unusually high, such as some regions of Ramsar and Abegarm-e-Mahallat in Iran. Such places are still insufficiently explored in terms of their biodiversity. In this study, strains isolated from six geothermal springs with elevated natural radiation were investigated. The highest concentration of ²²⁶Ra were 13,000 Bq.kg^-1 in the soil and 130 Bq.l^-1 in water respectively. The morphological and molecular analyses revealed, that the strains are not classifiable to any existing taxon. Therefore, they are described as new taxa for science. Based on results of our study, two earlier described species are transferred into newly established genus.

A new monotypic diatom genus from Laos is described, Okhapkinia alexandrii Glushchenko, Kulikovskiy et Kociolek gen. et sp. nov. The new genus is described on the basis light and scanning electron microscope observations. This genus is similar morphologically to the genus Sellaphora Mereschkowsky on the basis of several shared features. These features include presence of uniseriate striae, internal hymenate pore occlusions, large, elongate helictoglossae, round depressions at the valve face mantle junction, straight internal raphe slit, presence of longitudinal lines positioned on either side of the axial area, and striae arrangement and shape. The new genus is diagnosed by having an external, undulate raphe slit, absence of polar bars, presence of massive basal siliceous layer, and presence of rims and external thickenings around the areolae, central raphe ends curved to different sides internally and very prominent elongated hymenes internally. In all of these features the new genus differs from Sellaphora. The shared features between Okhapkinia gen. nov. and Sellaphora suggest the new genus should be assigned to the Sellaphoraceae Mereschkowsky. Similarites between Okhapkinia gen. nov. and other newly-described genera are discussed. We consider the newly described genus Altana Kulikovskiy, Lange-Bertalot et Metzeltin, which shares the feature of external silica outgrowths with Okhapkinia gen. nov. to be part of the family Cavinulaceae D.G. Mann. The genus Buryatia Kulikovskiy, Lange-Bertalot et Metzeltin described from Lake Baikal may represent another genus closely related to Sellaphora, and suggest it is also a member of the family Sellaphoraceae.

The family Radiococcaceae sensu lato, defined as colonial autospore-producing mucilaginous coccoid green algae, is widespread in terrestrial and freshwater habitats. Three species of Radiococcaceae sensu lato, including two Radiococcus species and one Planktosphaeria species, were described from China by light and electron microscopy. A new species of Planktosphaeria, Planktosphaeria hubeiensis sp. nov. was erected based on morphological comparisons and genetic analyses. Our phylogenetic analyses indicated that Radiococcaceae sensu lato is polyphyletic, and separated into three lineages. The Radiococcus species did not cluster into a monophyletic group in phylogenetic analyses; therefore the taxonomy of the genus Radiococcus should be revised in the future.

One of the observed flagellates, Cryptella cyanophora Pascher, is probably the first discovery ever of this species with cyanelles after more than 80 years since its description. This species was previously classified into the cryptophycean genus Chroomonas Hansgirg (see Discussion), which is why the observations of two common species, Chroomonas nordstedtii Hansg. and Ch. caudata Geitler, from natural water bodies are also presented and the theory of their cytological evolution is discussed. Similar uncertainty is associated with the origin of blue-green chloroplasts of some dinoflagellates, two species of which (from Czech waters) are presented, namely Gymnodinium aeruginosum Stein and Amphidinium amphidinioides (Geitler) Schiller. Again the theory of the origin of their chloroplast is discussed. The indubitable syncyanosis is demonstrated on Glaucocystis nostochinearum Itzigsohn.

During a survey conducted on the soil diatom flora of newly exposed areas due to the retreat of the Ecology Glacier (King George Island, South Shetlands) an unknown Muelleria taxon was observed that could not be identified using the currently available literature. Based on detailed morphological observations using LM and SEM microscopy the unknown taxon has been described as new for science - Muelleria olechiae sp. nov. The new species is characterized in having typically bifurcated terminal raphe fissures, elongated, deflected proximal raphe endings and a lack of canal puncta. It was observed in several soil samples, but always in relatively low abundances.

Six strains of Cyanobacteria sampled in the Brazilian Atlantic rainforest and one strain from Kauai, Hawaii, were studied using morphological and molecular approaches, including 16S rRNA gene phylogenies and 16S-23S ITS secondary structures, and are herein described as Komarekilla atlantica gen. et sp. nov.. Morphologically they are similar to Nostoc, Desmonostoc, Halotia, and Mojavia and indistinguishable from Chlorogloeopsis. The parsimony and Bayesian phylogenies of the 16S rDNA show that these strains are close to nostocacean strains, in strongly supported clades and separated from all other genera. The secondary structures of the 16S-23S ITS were very consistent between strains of K. atlantica, but distinctly different from structures in other close taxa. Of special note, the Hawaiian strain of K. atlantica had 16S sequence identities of 99.5-100% to the Brazilian strains, and 16S-23S ITS sequence identities of 99.4-99.8% to the Brazilian strains, and consequently likely represents a very recent introduction of the species to Kauai from South America, the geographic source of many of the non-native plants in the Hawaiian Archipelago.

The extensive genetic cryptic diversity revealed by molecular studies in many green microalgae has caused great uncertainties in the circumscription of some species described on strictly morphological grounds. These uncertainties should be resolved by obtaining molecular data from type materials, but this procedure is not feasible in many species because the type specimens are illustrations, or too small or poorly preserved to obtain DNA sequence data. In these situations, the selection of an epitype is often a mandatory requirement to define the identity of a species and establish unambiguously its position in molecular phylogenies. In this study we investigated the identity of two widespread species of Klebsormidium (Streptophyta), K. flaccidum and K. nitens, which were recently epitypified by Mikhailyuk and colleagues. We collected several specimens of these algae from the type localities and the original habitats of these two species, for which we examined morphology in the field material and in culture, and obtained sequences of the rbcL gene. On the basis of the original descriptions, we conclude that the designation of the epitype of K. flaccidum was correct, whereas the epitype of K. nitens (which consists of material collected tens of thousands of km from the type locality) was most probably incorrect. We discuss the implications of these decisions for the classification of Klebsormidium and, more generally, the importance of the correct choice of epitype material for the taxonomy of green microalgae.

Type material of Encyonema angustecapitatum Krammer was investigated to establish the identity of several Brazilian Encyonema populations. In order to elucidate the differences and similarities of that species complex, morphological features under light and scanning electron microscopy were detailed. Notes on their distribution were also discussed. MDS analysis distinguished four Encyonema species presently described as new to science: Encyonema acquapurae sp. nov., Encyonema sparsistriatum sp. nov., Encyonema tenue sp. nov. and Encyonema paradisiacum sp. nov. The four new species can be separated on the basis of a combination of the following morphological features: valve outline, axial area, valve length, valve width, length to width ratio, number of striae in 10 μm and number of areolae in 10 μm. Regarding ecological preferences, all four species were mainly found in oligotrophic and oligo-mesotrophic environments.