Chara inconnexa Allen a été trouvé dans le sud de la Sibérie orientale. Les spécimens sont décrits en détail. C'est une espèce très rare avec une large distribution et elle est principalement recensée dans les zones tempérées et subtropicales de l'hémisphère Nord. Cette espèce d'eau douce est trouvée dans différents types de plans d'eau. Les causes de la rareté de cette espèce et les aspects taxonomiques sont discutés. Considérant que l'holotype ne pouvait pas être identifié aux fins d'assurer le lien entre le nom de ce taxon et la description, son épitype devrait être conservé. Les problèmes taxonomiques des espèces subgymnophyllous et des formes proches de C. contraria A. Braun ex Kütz. s.str. sont décrits. La réévaluation de la valeur taxonomique des caractères de Rameau et l'application de critères supplémentaires dans l'approche polyphasique sont nécessaires. L'ensemble de ces caractères permettra de reconnaître des espèces subgymnophyllous comme une espèce distincte ou formes de C. contraria ou confirmer l'hypothèse que ce sont simplement un stade de l'ontogenèse ou morphogenèse anormale de C. contraria.

The Charales, commonly known as stoneworts, are a group of highly complex green algae that comprise one extant family (Characeae) with six genera. The aim of this study was to collect Charophytes in eastern and north of Iran and check the distribution maps of species in Iran. Samples were collected from 103 localities and 7 species have been determined with Chara braunii Gm., Chara globata Mig. and Lamprothamnium papulosum (Wallr.) J. Gr. recorded for the first time in Iran. Although Chara vulgaris and Chara gymnophylla were reported as widespread in north and eastern Iran, specimens of Chara vulgaris were collected in a wide variety of habitats from most of the provinces rendering this taxa the most abundant Charophytes in Iran (88 populations). Other species were restricted to few locations: Chara braunii, a cosmopolitan species, was limited to two locations in north Iran. Chara globata was found in a single location (Targhrud Lake). Most specimens of Chara contraria and Chara connivens were collected from South West Iran (260–350 m elevation). Lamprothamnium papulosum, a rather uncommon species in Asia, was found in a single lake with marine water characteristics in northeast Iran.

Proliferations of cyanobacteria are becoming increasingly widespread in many artificial reservoirs, and may have detrimental effects on ecosystem functioning, especially when the water sustains commercial fisheries. This is the case of the Bir M'Cherga reservoir in North Tunisia, where sporadic fish die-offs have been recently reported. A two-year survey investigated a dual-community structure including both phytoplankton and the main fecal bacterial indicators facing to environmental factors.

Low abundances of fecal indicator bacteria were recorded, indicating that no direct human contamination had occurred. However, the ecological status of this reservoir did show signs of degradation, Bacillariophyceae being superseded by Cyanobacteria, with a “nearlyexclusive” dominance of Planktothrix agardhii lasting several months, in association with Planktolyngbya limnetica and Pseudanabaena limnetica. In contrast, the rapid decline of P. agardhii observed in spring 2007 favored greater phytoplankton diversity, with the summer occurrence of Cylindrospermopsis raciborskii. Even though no significant relationships were identified between fish mortality and biological factors, the very presence of two bloomforming and potentially toxic cyanobacterial species may be viewed as a potentially serious issue with regard to water use and fish farming in the Tunisian reservoir.

Phymatolithon lusitanicum is a new maerl species described based on an integrative systematic approach including molecular (COI-5P, psbA) and morphological data obtained from recent collections, as well as comparison of type material from the morphologically and ecologically alike NE Atlantic species P. lamii and P. laevigatum. Molecular analyses including type material of P. lamii and P. laevigatum were congruent in delimiting P. lusitanicum as an independent lineage from these crustose species. The three species shared a common external morphology of multiporate asexual conceptacles, but P. lusitanicum has been detected only unattached as maerl while P. lamii and P. laevigatum are crustose. Phymatolithon lusitanicum is particularly abundant in subtidal maerl beds of the Atlantic Iberian Peninsula (Galicia and the Algarve); however it has also been detected northwards in Ireland intertidally and in Western Mediterranean Sea (Alborán Sea, Balearic Islands) down to 64 m. Phymatolithon lusitanicum differs from other Phymatolithon species reported for the European coasts mainly by the external shape of the multiporate asexual conceptacles (pore plate flush with surface or slightly sunken without a conspicuous thick raised rim) and its unattached habit as maerl/rhodolith. In addition, the lectotype of Lithothamnion hamelii turned out to be conspecific to Phymatolithon calcareum, therefore this taxon is proposed as a heterotypic synonym of P. calcareum. Finally, our molecular analyses detected cryptic diversity within the European collections of Phymatolithon, while collections identified as P. lenormandii from Canada or P. repandum from New Zealand were resolved as unrelated to the remaining Phymatolithon. In the light of these results, it is clear that further work is necessary to resolve species diversity within the genus Phymatolithon and its relationship with related genera.

In the cited article, we proposed the new combination Yonagunia ligulata (Harvey ex Kützing) Manghisi, M. Morabito, De Clerck & Le Gall. In this note, we add the lectotypification of its basyonym, Gymnogongrus ligulatus Harvey ex Kützing.