A new Peyssonnelia species from shallow water habitats in southwest Puerto Rico is described. Peyssonnelia stratosa is yellowish beige or reddish in color and is composed of small overlapping blades 2–3 cm in diameter and forms extensive colonies. Peyssonnelia stratosa exhibits small cells at mid level in the perithallus, both immediate distal and proximal cells being much longer, giving the appearance of stratification within the perithallus. Tetrasporangia, cut off laterally from an enlarged proximal nemathecial cell, reach 190 µm in length.

Skeletonema costatum like cells are recorded globally and often generate a huge biomass when blooming. In the present study we performed a taxonomic and geographic survey of the species diversity in Skeletonema along the Chinese coastline. We concentrated our efforts on Xiamen Harbour, where we followed the annual cycle of the generic diversity by collecting 51 water samples from 2006 to 2010. A total of 687 strains of Skeletonema were established and they were identified as S. ardens, S. costatum, S. dohrnii, S. grevillei, S. menzelii, and S. tropicum. S. dohrnii is a winter-spring species, whereas other species tend to appear in summer and autumn. S. costatum is the single species present throughout the year. To assess how the species overcome the period in which they are not detectable in the water column we also sampled the surface sediments and either isolated resting stages and incubated them into cultures, or we generated monoclonal strains by incubating the sediment and isolated whatever emerged from it. The above six species except S. grevillei, and S. pseudocostatum as well, were detected this way, implying that the species produce resting stages. Resting cells of S. costatum and S. tropicum were actually observed in the sediment.

Sporolithon ptychoides Heydrich (Sporolithaceae, Sporolithales), the type species of the genus Sporolithon, is newly reported for Thai waters based on specimens collected from the Gulf of Thailand and the Andaman Sea. A detailed morphological and anatomical account is provided, including comparisons with published data of S. ptychoides and its related species. Epithallial cells are flared. Cells of adjacent filaments connect laterally mostly by secondary pit connections. Tetrasporangia are grouped in sori that occur in patches over the thallus surface. Sori are buried in distinct rows in the thallus. Details of male, female and carposporangial conceptacles of S. ptychoides are described for the first time. Gametangial thalli are monoecious with spermatangia and carposporangia born in uniporate conceptacles. Dendroid spermatangial branches occur on the floor, walls and roof of the male conceptacle chamber. Carpogonial branch consists of a hypogenous cell and a carpogonium. Central fusion cell is absent on the floor of the carposporangial conceptacle chamber.

The ultrastructural features of oospore wall ornamentation in endemic and critically endangered Balkan Charophytes were examined using scanning electron microscopy (SEM). The present study shows for the first time, in this amount of detail, the interspecific variations in the oospore of endemic and rare Charophytes in the genus Chara from the Balkan Peninsula, which will assist in the correct determination and taxonomy of this genus. Oospore features are presented in detail as the background for some additional tips, including the length and width of the oospore, the fossa width, the number of striae and the length to width ratio. Based on oospore ultrastructure, the taxonomic relationships between the endemic Chara conniventi-fragilis and C. connivens, C. visianii and C. intermedia species are discussed.

Madame Marie Lemoine was one of the most prolific taxonomists on fossil coralline red algae (Corallinales, Rhodophyta) during the 20^th Century. She described three non-geniculate genera and over 90 species. Samples from all over the world were sent to her, and she usually sent them back to the collectors. Thus, a significant number of her types are housed in different institutions or might be lost. Some, however, are housed in the herbarium at the Muséum national d'histoire naturelle in Paris (PC) where she worked for most of her life. We found the original material of nine fossil coralline species at PC: 1) three species from Haute-Savoie (France) [Lithothamnium moretii, Lithophyllum simplex and Jania nummulitica]; 2) five species from Albania [Lithothamnium corallinæforme, Lithothamnium bourcartii, Lithophyllum koritzæ, Lithophyllum sphæroides and Lithophyllum (?) albanense]; and 3) one species from SW France but originally described from the Carpathian Mountains [Lithothamnium abrardii]. The aim of this paper is to reassess the newly discovered original material in a modern taxonomic perspective and to typify the species for which Marie Lemoine did not establish a holotype.

Several of these species have been frequently reported by palaeophycologists. The species albanensis, either within Lithophyllum or Spongites, and Lithothamnion moretii are among the five most cited species of fossil corallines in the literature published during the XX century. Lithophyllum simplex is among the nine most cited fossil coralline species but its taxonomic circumscription cannot be confidently established because no reproductive structures can be identified in the type.