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Chara gymnophylla is one of the first charophyte species reported for Serbia during the late 19th and the early 20th centuries, and at that time it was the second in terms of the frequency of its occurrence in the country. General taxonomic misinterpretations in the past resulted in the concealment of another species, C. squamosa, within the findings attributed to C. gymnophylla. In Serbia, Chara gymnophylla was treated as C. vulgaris var. gymnophylla, and as such was not listed as a species inhabiting the country. Recent improvements in the taxonomic concept for C. squamosa prompted a revision of the rich material of C. gymnophylla, C. vulgaris var. gymnophylla, C. vulgaris var. nitelloides, and C. rohlenae, deposited in the BEOU collection. The revision process was conducted concurrently with fieldwork and the collection of new material. Our study confirmed the presence of C. squamosa in Serbia for the first time. Based on numerous revised samples from the BEOU collection, as well as recently collected specimens, the species’ continuous presence in Serbia since 1976 was confirmed. Chara squamosa and C. gymnophylla were thus added to the list of Characeae species inhabiting Serbia, and categorised as Critically Endangered according to the criteria outlined by IUCN. An overview of the biogeography, ecology and taxonomy of C. squamosa in Serbia is provided, particularly in relation to C. gymnophylla. The BEOU charophyte collection proved to represent a valuable and relevant resource for critical taxonomic revisions. The results presented in this study strongly encourage further studies on C. squamosa and C. gymnophylla distribution in the Balkan region and wider area in order to gain a deeper understanding of the species’ ecology and the further improvement of their taxonomic concepts., Chara gymnophylla jedna je od prvih vrsta pršljenčica zabeleženih u Srbiji krajem 19. i početkom 20. veka, i tada je na našim prostorima bila druga po učestalosti javljanja. Pogrešna taksonomska tumačenja u prošlosti dovela su do toga da je još jedna vrsta, C. squamosa, bila skrivena među nalazima vrste C. gymnophylla. Chara gymnophylla je pak kasnije u Srbiji taksonomski tretirana kao varijetet - C. vulgaris var. gymnophylla, i kao takva nije bila na listama vrsta koje naseljavaju teritoriju Srbije. U skorije vreme sugerisan je novi taksonomski koncept za vrstu C. squamosa, što je podstaklo reviziju bogatog materijala C. gymnophylla, C. vulgaris var. gymnophylla, C. vulgaris var. nitelloides i C. rohlenae, deponovanih u kolekciji BEOU. Proces revizije se odvijao paralelno sa terenskim istraživanjima i prikupljanjem novog materijala. Naša istraživanja su pokazala po prvi put prisustvo vrste C. squamosa u Srbiji. Zasnovano na brojnim revidiranim uzorcima iz kolekcije BEOU, kao i uzorcima prikupljenim u novije vreme, povrđeno je kontinuirano prisustvo ove vrste u Srbiji počev od 1976. godine. Chara squamosa i C. gymnophylla su dodate na listu vrsta pršljenčica koje naseljavaju teritoriju Srbije i klasifikovane su kao kritično ugrožene (CR) prema kriterijumima IUCN. U ovom radu dat je biogeografski, ekološki i taksonomski pregled vrste C. squamosa u Srbiji, u odnosu na vrstu C. gymnophylla. Kolekcija pršljenčica BEOU se pokazala kao dragoceni i relevantni resurs za kritičke taksonomske revizije. Rezultati prezentovani u ovoj studiji snažno podstiču dalja istraživanja distribucije vrsta C. squamosa i C. gymnophylla na Balkanu i na širem području, kao korak ka daljem rasvetljavanju njihove ekologije i utemeljenju taksonomskih koncepata.

This paper presents new records and noteworthy data on the following taxa in SE Europe and adjacent regions: diatom algae Cyclostephanos invisitatus, Cyclotella meduanae, and Stephanodiscus lacustris, mycorrhizal fungi Alessioporus ichnusanus and Amanita mairei, saprotrophic fungi Diaporthe oncostoma, Stropharia albonitens and Pseudomassaria chondrospora, lichenised fungus Acrocordia subglobosa, stonewort Chara connivens, mosses Buxbaumia viridis, Tortella fasciculata and Tortula protobryoides, monocots Epipactis pontica Gymnadenia frivaldii, and Orchis italica and dicots Callitriche brutia, Callitriche platycarpa and Epilobium nutans are given within SE Europe and adjacent regions.

This paper presents new records and noteworthy data on the following taxa in SE Europe and adjacent regions: saprotrophic fungus Geastrum morganii, Guignardia istriaca and Hypoxylon howeanum, mycorrhizal fungus Amanita friabilis and Suil- lus americanus, xanthophyte Vaucheria frigida, stonewort Chara hispida, liverwort Calypogeia integristipula and Ricciocarpus natans, moss Campylopus introflexus, Dicranum transsylvanicum, Tortella pseudofragilis and Trematodon ambiguus, fern Ophioglossum vulgatum subsp. vulgatum, monocots Epipactis exilis, Epipactis pur- purata and Epipogium aphyllum and dicots Callitriche cophocarpa, Cornus san- guinea subsp. hungarica and Viscum album subsp. austriacum are given within SE Europe and adjacent regions.

Charophyte research in SNR Zasavica started in 1998, and by 2010 a total of 9 species were recorded, most of which are categorized as critically endangered in Serbia. Charophytes was recorded primarily in small and ephemeral water bodies - puddles, ponds, even ruts, emphasizing significance of those for biodiversity. After the extraordinary results recorded in this period, the research continued in 2014 and in this paper we will present the results of the research until 2020. The results of this study confirmed two new taxa in the territory of Zasavica, Nitella gracilis and N. opaca, both critically endangered species in Serbia, but also the absence of one previously recorded taxon - N. capillaris. A shift in the representation of charophyte taxa was also noted, increased presence of the genus Chara representatives, and a decreased presence of the genus Nitella representatives was noted. The continuation of research, primarily in the direction of regular monitoring, will contribute to detailed mapping of the distribution of charophytes in Zasavica, but also to general knowledge of the ecology of rare and endangered species and their specific habitats. Finally, continuous monitoring will guide managers towards the selection of adequate protection measures in order to preserve the sensitive habitats and charophytes diversity in Zasavica.

According to the latest checklist, updated in December 2022, 25 species of charophyte algae are registered on the territory of Serbia. These data are gathered in a number of projects and finally integrated within the project related to the production of Red books and Red Lists of flora, fauna and fungi on the territory of the Republic of Serbia. The crown results of this work are preliminary Red Lists for all organism groups, including charophyte algae. The lists were produced in accordance with IUCN criteria, using an application especially created for the purpose of this project. According to IUCN criteria, all charophyte species registered on the territory of Serbia are Red Listed, that is, belong to one of the three categories – Critically Endangered (CR) – ten species, Endangered (EN) – seven species, and Vulnerable (VU) – seven species, except one species which is Data Deficient. The main factors endangering the flora of charophytes in Serbia are habitat fragmentation and desiccation, which were accordingly used as the main criteria to assess charophyte species status. Here we present the process as well as the results of the assessment and discuss the main factors of endangerment.

Akumulacije predstavljaju važan vodni resurs namenjen dugoročnom snabdevanju vodom za piće, ali uprkos tome ne postoji adekvatan plan njihove zaštite. Predmet ove doktorske disertacije jeste praćenje prostorne i vremenske dinamike fitoplanktona akumulacije Vrutci, sa posebnim osvrtom na dinamiku potencijalno toksične cijanobakterije Planktothrix rubescens. Analiza je obuhvatala utvrđivanje sastava, brojnosti i biomase fitoplanktona na tri lokaliteta (Vodozahvat, Nikolići i Omar) i duž vodenog stuba tokom perioda od decembra 2013. do decembra 2015. godine. Pored toga praćeni su i osnovni fizički i (bio)hemijski parametri, takođe po mesecima i po dubini. Osnovni cilj studije je bio prikaz prostorne i vremenske dinamike vrste P. rubescens, otkrivanje najznačajnijih parametara odgvornih za njenu proliferaciju u akumulaciji, kao i procena uticaja „cvetanja“ ove cijanobakterije na dinamiku ostalih članova fitoplanktonske zajednice. Najveća brojnost i biomasa P. rubescens zabeležene su u julu 2015. godine na 6 m dubine (963855 ćel/ml odnosno 30,23 mm3/l) na lokalitetu Vodozahvat. Rezultati su pokazali da su temperatura vode i stabilnost vodene kolone faktori koji u najvećoj meri određuju rast P. rubescens, kao i da ova cijanobakterija ima uticaj na dinamiku drugih algi i cijanobakterija. P. rubescens je tokom perioda stratifikacije formirala metalimnionski maksimum hlorofila a praćen maksimumom koncentracije kiseonika (supersaturacija). Takođe, rezultati su pokazali da rast P. rubescens nije bio toliko uslovljen koncentracijom ispitivanih nutrijenata, iako je akumulacija u proseku bila eutrofna. Neophodno je sprovođenje organizovanog monitoringa osnovnih parametara kvaliteta vode, kao i redovno praćenje vertikalne distribucije biomase P. rubescens u akumulaciji Vrutci., Reservoirs represent an important water resource intended for long-term supply, but despite that, there is no adequate plan for their protection. The subject of this dissertation is the survey of spatial and temporal dynamics of phytoplankton of the Vrutci reservoir, with special reference to the dynamics of the cyanobacterium Planktothrix rubescens. The analysis included determining the composition, abundance and biomass of phytoplankton at three sites (Vodozahvat, Nikolići i Omar) and along the water column during the period from December 2013 to December 2015. In addition, the basic physical and (bio)chemical parameters were also monitored by months and by depth. The aim of the study was to review the spatial and temporal dynamics of P. rubescens, to discover the most important parameters of its blooming in the reservoir and to assess the impact of this cyanobacterium on other members of phytoplankton. The highest abundance and biomass of P. rubescens were recorded in July 2015 at a depth of 6 m (963,855 cells/ml and 30.23 mm3/l, respectively) at the Vodozahvat. The results showed that water temperature and water column stability are the factors that largely determine the growth of P. rubescens, and that this cyanobacterium has a great influence on the dynamics of other algae and cyanobacteria. P. rubescens formed a metalimnion maximum of chlorophyll a during the stratification period, followed by a maximum of oxygen concentration (supersaturation). Also, the results showed that the growth of P. rubescens was not so much conditioned by the concentration of the nutrients, although the reservoir was eutrophic on average. It is necessary to conduct organized monitoring of the basic parameters of water quality as well as regular monitoring of the vertical distribution of P. rubescens biomass in the Vrutci reservoir.

Various studies report contrasting results on the substrate-type effect on diatom community composition, but the particularly important question is whether or not it affects diatom-based assessments of water quality. We investigated whether the substrate type is a significant predictor of the diatom community composition and if it affects lake water quality assessment based on diatom indices. This study took place in Sava Lake (Serbia). We used glass, ceramic, willow and yew tree tiles as artificial substrates for periphyton development, and pebbles from the lake littoral as natural substrate. Results revealed differences in both the diatom community composition and diatom indices values related to the substrates. A distinction was recognized between natural, artificial wooden, and artificial inert substrates. However, the final lake quality assessment based on diatom indices was more or less similar in all substrate types in our study, and depended on value ranges associated with water quality classification and on diatom index choices. Artificial substrates in our study did show potential as an alternative for natural substrate, but further studies are required, particularly in various types of lentic ecosystems to confirm our findings and support artificial substrate employment in lake water quality assessment., Diverses études rapportent des résultats contrastés sur l'effet du type de substrat sur la composition de la communauté de diatomées, mais la question particulièrement importante est de savoir si cela affecte ou non les évaluations de la qualité de l'eau basées sur les diatomées. Nous avons cherché à savoir si le type de substrat est un prédicteur significatif de la composition de la communauté de diatomées et s'il affecte l'évaluation de la qualité de l'eau des lacs basée sur les indices de diatomées. Cette étude a eu lieu dans le lac Sava (Serbie). Nous avons utilisé des carreaux de verre, de céramique, de saule et d'if comme substrats artificiels pour le développement du périphyton, et des galets du littoral du lac comme substrat naturel. Les résultats ont révélé des différences dans la composition de la communauté de diatomées et dans les valeurs des indices de diatomées liées aux substrats. Une distinction a été reconnue entre les substrats naturels, artificiels en bois et artificiels inertes. Cependant, l'évaluation finale de la qualité du lac basée sur les indices de diatomées était plus ou moins similaire dans tous les types de substrats de notre étude, et dépendait des plages de valeurs associées à la classification de la qualité de l'eau et des choix d'indices de diatomées. Les substrats artificiels dans notre étude ont montré un potentiel comme alternative au substrat naturel, mais des études supplémentaires sont nécessaires, en particulier dans divers types d'écosystèmes lentiques pour confirmer nos résultats et soutenir l'utilisation de substrats artificiels dans l'évaluation de la qualité de l'eau des lacs.

This paper presents new records and noteworthy data on the following taxa in SE Europe and adjacent regions: cyanobacteria Anagnostidinema amphibium, mycorrhizal fungus Tricholoma frondosae, stonewort Chara connivens, mosses Dicranum polysetum and Ulota intermedia, and dicots Eclipta prostrata, Paeonia daurica subsp. daurica, Ruta graveolens and Sorbus bosniaca.

Aerophytic phototrophs, colonizers of different substrates exposed to air, among which are rock substrates in cave habitats, are in general not sufficiently investigated and studied. From the ecological point of view, seasonal/temporal variations and parameters that influence aerophytic phototrophic communities through seasons still remain largely unknown. Seasonal analysis of phototrophic microorganisms from biofilms developed at entrances of Samar and Jezava caves in Eastern Serbia was performed four times a year. All identified phototrophic representatives were assigned to a certain division or group. The relationship between documented groups and different measured, determined and observed ecological parameters was illustrated using principal component analysis (PCA). A high diversity of cyanobacteria and algae was observed as a result of seasonal sampling: 141 taxa in Samar and 61 taxa in Jezava Cave. Cyanobacteria were dominant in both caves (coccoid forms prevailing) and were followed by Bacillariophyta. Bacillariophyta were positively correlated with light intensity and sites where seeping water was present, and cyanobacteria with water content in biofilm, Chl a and relative air humidity. Higher diversity of phototrophs was documented in December and March, and lower in May and August in both caves with Chl a values having the same trend as the diversity of phototrophic microorganisms. This was especially the case with biofilms in which diversity was more prone to seasonal changes and where Cyanobacteria dominated. Only 24 taxa were documented during all four seasons in Samar Cave (Cyanobacteria, Bacillariophyta and Chlorophyta representatives) and three in Jezava Cave (Cyanobacteria only).

Phosphorus overenrichment of shallow ponds prevailing in wetlands leads to their eutrophication causing the collapse of those vulnerable habitats. The potential of phosphorus accumulation by periphyton developed on artificial substrata has been investigated in two shallow ponds (Baračka and Široki Rit) in northwest Serbia and compared to the same ability of plankton and metaphyton. The periphyton substrate carrier has been submerged from May to October. Both continuously (CS) and monthly developed (MS) periphyton were sampled. Autotrophic component of all investigated communities has been qualitatively assessed. Maximum accumulation of only 14.7 mg TP/m2 was recorded in three-month exposed periphyton CS. MS exposed from July to August reached maximal 12.7 mg TP/m2. Plankton community that was characterized by more diverse and abundantly developed algal component was more effective in phosphorus accumulation (0.7 mg/g dry weight) in comparison with dominantly inorganic and diatom-dominated periphyton in Baračka. Unstable conditions caused by recent revitalization (dredging organic matter and mud from pond basin—redigging) as well as rapid desiccation of Široki Rit disabled making an unambiguous conclusion about the efficiency of phosphorus accumulation among different communities, but suggested slight potential of phosphorus harvesting by metaphyton in this pond. Due to the shorter exposure time that brings the reduced risk of unpredictable changes in the ecosystem, as well as the considerable amount of accumulated phosphorus, large-scale application of one-month exposed periphyton developed on artificial substrates would be more advisable for phosphorus harvesting in nutrient affected shallow ponds.

Charophyte species delineation is regularly based on a set of thallus morphological character- istics, but considering pronounced phenotypic plasticity, difficulties and doubts commonly occur in Chara species determination. DNA barcoding may contribute to solving these chal- lenges. Here we characterize Chara contraria with an unusual set of morphological character- istics, and specimens morphologically resembling Chara connivens collected in Serbia, by describing their morphological traits and analysing matK barcoding results. Our results indi- cated that dioecious Chara specimens, tentatively determined as Chara “connivens” based on morphological traits, were genetically more closely related to C. globularis. These Chara “connivens” specimens formed a sister group to a monophyletic C. globularis cluster, suggesting that it may be neither C. connivens nor C. globularis. We strongly encourage further barcoding of C. “connivens” samples from freshwater, in order to find out if there are consistent genetic differences between the dioecious freshwater C. “connivens” and monoecious C. globularis. Barcoding of matK placed the monoecious Chara specimens, which based on morphological characteristics initially were determined as C. virgata, into the C. contraria group. This indicates that the microscopic traits which commonly are used for Chara species determination some- times are misleading. In general, our study challenges the commonly used phenetic species concept in Charophyte taxonomy and illustrates the importance of molecular approaches to evaluate the validity of morphological characteristics of the plant thallus in species delineation.

Phototrophic microorganisms from two caves in Serbia (Podpeć and Stopić) were examined. Samples were taken from the entrances where natural light was present, as well as from the inside caves near artificial light (lampenflora community). Cyanobacteria, Chlorophyta, Bacillariophyta and Xanthophyta were documented, with 51 taxa in total. The highest number of taxa recorded in the Cyanobacteria were coccoid cyanobacteria; Gleocapsa and Chroococcus were dominant. According to the redundancy analysis (RDA), Cyanobacteria were dominant at cave entrances while other groups (Chlorophyta, Bacillariophyta and Xanthophyta) were documented in lampenflora samples. Temperature, relative humidity, and light intensity were measured, as well as chlorophyll a concentrations and biofilm parameters (water, organic and inorganic matter content). Ecological parameters did not show significant variation, while light intensity de-pended on the position of sampling sites. RDA showed that the water content was higher in biofilm samples from cave entrances, while levels of inorganic matter were increased in lampenflora samples. The concentration of chlorophyll a did not show significant correlations with any of the measured ecological or biofilm parameters. Although the ecological parameters inside the cave did not show significant variation, they should be monitored because of the potential influence on the development of the lampenflora community that has a negative aesthetic impact on cave formations.

Due to life in extreme environments, cyanobacteria and algae from cave biofilms that form at the entrances or deep inside the cave around artificial lights are of increasing interest to many scientists. It is well-known that many phototrophic microorganisms are first to colonize exposed substrata and produce the organic matter on which other biofilm constituents relly. Many studies dealing with phototrophic microorganisms from biofilms focus on the diversity and community composition of cyanobacteria and algae, while quantitative assessments are rarely implemented. Biofilm sampling was conducted in Degurić and Vernjikica Cave located in Western and Eastern Serbia, respectively. Ecological parameters (temperature, relative humidity, light intensity) and distance from the entrance were measured. Additionally, chlorophyll content, as well as biofilm parameters (water content, organic and inorganic matter) were determined. The abundance of phototrophic microorganisms was assessed on microscope slides which contained 1 mg of biofilm that was dehydrated for a short period of time and homogenized prior to slide preparation, and then rehydratated. The biomass of recorded cyanobacterial and algal taxa was calculated by applying geometric approximations and standard mathematical formulas. In Degurić Cave, at the sampling site where the highest biomass was documented, the higher diversity, water content and chlorophyll values were also recorded, while in Vernjikica Cave a high content of organic matter was documented. According to the multivariate analyses performed, the biomass of simple trichal Cyanobacteria, Bacillariophyta, and Xanthophyta was positively correlated with the content of organic matter in biofilm and light intensity, while coccoid and heterocytous Cyanobacteria and Chlorophyta showed a positive correlation with water content in the biofilm, relative humidity and distance from the entrance. The total biomass was positively correlated with the chlorophyll conte

Cyanobacterial blooms have become common all over the world, negatively affecting various ecosystem components. Planktothrix rubescens is a planktonic cyanobacterium that frequently causes blooms in temperate (mostly mesotrophic) lakes in Europe and, unlike other cyanobacteria, it is usually associated with ecosystem re-oligotrophication. The potential effects of P. rubescens on periphyton development have not been estimated in any recently published studies. The objective of the present paper was to assess how a Planktohrix rubescens bloom affects periphyton development in a temperate freshwater reservoir. A field study was performed in the Vrutci reservoir (western Serbia), where P. rubescens blooms have occurred since December of 2013. Periphyton was grown on glass slides that were incubated following lake stratification and sampled monthly from July to October of 2015. Dry mass, ash free dry mass and content of chlorophyll a, as well as composition of the community of developed periphyton, were estimated, together with P. rubescens biomass in the water column at the particular depths where substrates for periphyton were incubated. The metalimnetic bloom of P. rubescens induced calcite precipitation on the incubated substrates, which was reflected in obstructed colonization. The periphyton community composition was mainly determined by the depth gradient, which was potentially related to reduced light availability driven by shading effects caused by the P.rubescens bloom. Our results provide a significant update on periphyton ecology in relation to cyanobacterial blooms, elucidating complex interactions in the ecosystem. They also represent a stimulus for further studies on the capacity of P. rubescens for induction of calcium carbonate precipitation in lakes.

Značaj perifitona ogleda se u velikom doprinosu primarnoj produkciji, protoku enеrgije i kruņenju nutrijenata u vodenim ekosistemima. U Srbiji su istraņivanja perifitona u jezerima malobrojna, a veńtačke podloge za razvoj perifitona do sada nisu bile upotrebljavane u metodologiji ekolońkih studija ove zajednice. Cilj studije na Savskom jezeru (leto 2014. godine) je bio procena uticaja različitih tipova veńtačkih podloga (staklo, keramika, vrba i tisa) i dubine inkubacije na razvoj perifitona i njegovu potencijalnu primenu u biomonitoringu. Deo istraņivanja koji je sproveden na jezeru Vrutci (leto 2015. godine) imao je za cilj ispitivanje uticaja cvetanja cijanobakterije Planktothrix rubescens na perifiton. U uzorcima perifitona mereni su netaksonomski, kao i kvalitativni i kvantitativni taksonomski parametri. Rezultati su pokazali da je dubina inkubacije na 50 cm od povrńine vode, kao i staklena veńtačka podloga najbolji izbor kod potencijalnog korińćenja netaksonomskih karakteristika perifitona u biomonitoringu. Struktura celokupne, kao i zajednice silikatnih algi, istakla je prioritetnu upotrebu inertnih veńtačkih podloga (stakla i keramike) u biomonitoringu. Taloņenje kalcita je prvi put detektovano kao posledica metalimnionskog cvetanja P. rubescens. Prisustvo ove cijanobakterije negativno se odrazilo na sve merene parametere perifitona. Fenomen zajednice silikatnih algi jezera Vrutci jeste veliki diverzitet i prisustvo 19 taksona koji se nalaze na Crvenoj listi slikatnih algi Nemačke, meĎu kojima izdvajamo Achnanthidium caledonicum, koji je dominirao u većini uzoraka i Aneumastus stroesei, koji je prvi zabeleņni predstavnik ovog roda u Srbiji. Nańi rezultati potencijalno ukazuju i na vińi stepen tolerancije silikatnih algi na prisustvo P. rubescens., The significance of periphyton in freshwater ecosystems is fundamentally reflected in processes of primary production, nutrient cycling and energy flow. In Serbia, periphyton surveys in lentic ecosystems are scarce, and artificial substrates as methodology for ecological studies of this complex community have not been applied yet. The Sava Lake part of the study (summer 2014) aimed to determine effects of substrate types (glass, ceramic, willow and yew) and incubation depths on periphyton development and it’s potential application in biomonitoring studies. Part of research that was conducted at the Vrutci Lake (summer 2015) aimed to investigate effects of Planktothrix rubescens bloom on periphyton. In periphyton samples, non taxonomic and both qualitative and quantitative taxonomic parameteres were measured. Our results suggest that when non taxonomic parameters employment in biomonitoring purposes is assumed, periphyton should be developed on glass substrate incubated in water layer up to 50 cm. Cyanobacteria and algae community structure also pronounced preferable use of inert types of artificial substrates (glass and ceramic) in biomonitoring studies. Our results represent the first report of calite precipitation induced by P. rubescens. Presence of this cyanobacterium negatively affected all measured periphyton parameters. The other phenomenon in the Vrutci Lake was diverse diatom community in periphyton and 19 diatom taxa listed in German Red List of diatoms. Among Red List taxa, Achnanthidium caledonicum, that dominated the most of samples and Aneumastus stroesei, that is the first representative of entire genus Aneumastus in Serbia are accentuated. Our results suggest the potentilly higher tolerance level of diatoms to the P. rubescens bloom.

Most field charophytologists have experienced that the morphology of Chara specimen can be intermediate” between two different species. We collected a Chara sample in lake Sava, close to Belgrade, Serbia. The habitus of this specimen resembled C. contraria, but the microscopic details (“spines”, stipulodes) resembled C. virgata. Preliminary analysis of the matK gene, however, clearly place the sample into C. contraria. This means that C. contraria sometimes may have stipulodes where only the upper row is elongated. We also collected a sample which orphologically resembled C. connivens in Dulin pond (44°51’11.5” N 21°17’52.2” E), Serbia. The sample was clearly dioecious, and we analysed male and female samples. Preliminary analyses of the matK gene placed this sample into a separate sub-cluster of C. globularis (i.e. not together with C. connivens, but an own sub-group within C. globularis). We will present the most recent results on these specimens.