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Dopo una breve introduzione sui 6 Ordini che costituiscono l’oggetto di questo secondo contributo alle Rhodymeniophycidae del Mediterraneo (Mar Nero escluso), si passa alla trattazione dei taxa seguendo l’ordine strettamente alfabetico.La trattazione riguarda 131 taxa correntemente accettati, di cui 126 a livello specifico e infraspecifico e 5 a livello solamente di genere. Inoltre vengono censiti 132 taxa (a livello specifico e infraspecifico) non accettati, nonché altri 280 taxa (a livello specifico e infraspecifico) sinonimi dei taxa accettati e/o non accettati. Dei 124 taxa a livello specifico e infraspecifico accettati, 96 sono componenti tradizionali della flora macroalgale mediterranea, 12 sono alieni o involontariamente introdotti, 16 sono taxa excludenda. Tutti i taxa accettati sono ripartiti in 39 generi di cui: 31 con rappresentanti in Mediterraneo, 3 sono excludenda, e 5 privi di rappresentanti in Mediterraneo (solamente citati nel testo). I 132 taxa non accettati sono così ripartiti: 47 sono taxa inquirenda (di cui 3 con nome illegittimo); 32 sono taxa con nome illegittimo (3 dei quali sono anche taxa inquirenda); 41 sono taxa con il nome invalidamente pubblicato (32 dei quali sono nomina nuda); 15 taxa sono combinazioni invalide. Di ciascun taxon trattato viene fornita una breve descrizione preceduta da alcuni riferimenti bibliografici riportanti notizie, illustrazioni e/o distribuzione in Mediterraneo. La trattazione della maggior parte dei taxa specifici e infraspecifici è corredata da tavole iconografiche; inoltre, quasi tutti i taxa trattati sono arricchiti di note bilingue (Italiano e Inglese) a supporto delle sinonimie indicate, o delle scelte tassonomiche seguite o delle motivazioni per cui il taxon è stato considerato inquirendum e/o excludendum o delle conclusioni nomenclaturali. Inoltre, vengono proposte 3 nuove combinazioni, 2 delle quali di taxa non presenti in Mediterraneo. Il lavoro è completato da un glossario di 173 voci, da un indice di tutti i nomi dei taxa citati nel testo e da una errata corrige al precedente lavoro sulle Rhodymeniophycidae di Cormaci et al. (2020).

Dopo una breve introduzione sulla consistenza numerica delle Rhodymeniophycidae (Rhodophyta) presenti in Mediterraneo (Mar Nero escluso), sugli "steps" programmati per la loro completa trattazione con la precisazione che questa prima parte riguarda i taxa dei 5 Ordini già elencati nel titolo e la presentazione di una tabella delle Rhodophyta nella quale i taxa superiori alle famiglie sono ordinati secondo un criterio filogenetico, si passa alla trattazione dei taxa seguendo l'ordine strettamente alfabetico. A seguito degli aggiornamenti tassonomico-nomenclaturali, i taxa a livello specifico ed infraspecifico ricadenti negli ordini sopra citati e presenti in Mediterraneo, sono risultati 132 (di cui 28 inquirenda). Questi a loro volta si raggruppano in 50 generi e 25 famiglie. Inoltre 46 taxa, di cui 1 a livello di famiglia e 45 a livello specifico ed infraspecifico sono stati considerati taxa excludenda; 31 taxa, a livello specifico e infraspecifico, sono stati considerati taxa inquirenda, di questi 3 sono anche excludenda e uno dei tre ha nome illegittimo. Inoltre viene evidenziata l'illegittimità dei nomi di 47 taxa (di cui 3 a livello di famiglia, 3 a livello di genere e 41 a livello specifico e infraspecifico), l'invalidità dei nomi di 29 taxa (di cui 1 a livello di genere e 28 a livello specifico ed infraspecifico) e l'invalidità di 9 combinazioni; infine, viene proposta 1 nuova combinazione. Di ciascun taxon trattato viene fornita una breve descrizione preceduta da alcuni riferimenti bibliografici riportanti notizie, illustrazioni e/o distribuzione in Mediterraneo; per la maggior parte dei taxa specifici sono state realizzate delle illustrazioni. Quasi tutti i taxa trattati sono arricchiti di note bilingue (Italiano e Inglese) a supporto delle sinonimie indicate, o delle scelte tassonomiche seguite o delle motivazioni per cui il taxon è stato considerato inquirendum e/o excludendum o delle conclusioni nomenclaturali. Il lavoro è completato da un glossario di 158 voci, da un indice di tutti i nomi dei taxa citati nel testo e da una errata corrige al lavoro di Cormaci et al. (2017).

A brief history of both nomenclature and taxonomy of ‘Callithamnion codii’ is presented. From the nomenclatural point of view, the implications deriving from considering it as validly published or not are presented. From the taxonomic point of view, the conspecificity of Colaconema codii and Colaconema caespitosum is reaffirmed.

Laminaria rodriguezii Bornet is a deep-water brown alga endemic of the Mediterranean Sea. Lectotypification of Laminaria rodiguezii has been based on both Bornet's protologue and the original material housed at the cryptogamic collections of the Museum National d'Histoire Naturelle de Paris (PC).

We investigated phytobenthos in submerged marine caves. Underwater caves have rarely been examined for floristic composition. The study was carried out in two Mediterranean marine protected areas (MPAs) [Plemmirio (Maddalena Peninsula, Syracuse, Ionian Sea) and Pelagean Islands (Straits of Sicily)] and the caves were chosen on the basis of their geomorphology, exposure, and bathymetry. From our comparative study of cave floras, we demonstrated that the macroalgal flora of each cave is influenced by the floristic composition of the adjacent area that is a natural source of recruits and by the light environment. Caves that are “visited” (i.e., those situated on one of the underwater routes for scuba divers visiting the MPAs) had floristic richnesses higher than those of “scarcely” or “not visited” ones (i.e., not on tourist routed). This is likely because the visited caves, due to their large entrance and shallow location, have good lighting that favors high macroalgal biodiversity.

This article gives an up-to-date review of the status of and main changes in benthic algal flora that have occurred in recent decades along the Italian Adriatic coastline. Common traits among the main structural/functional changes observed and their causes are discussed. A synthesis of the challenges to and prospects of filling gaps in the data, ecological knowledge and protection measures are also given.

SUMMARY The first occurrence of Palisada maris-rubri (K.W. Nam et Saito) K.W. Nam (Ceramiales, Rhodomelaceae) from the Mediterranean Sea, is reported. To date the species was known only from tetrasporic specimens from the type locality (Ras Muhammed, Sinai, Egypt, Red Sea). Mediterranean thalli share nearly all vegetative and reproductive features with Red Sea specimens showing more robust thalli with axes to 3 mm broad and ultimate branchlets to 1000 µm broad, absence of intercellular spaces between medullary cells and epidermal cells in transverse section with a palisade arrangement. Male and cystocarpic thalli are recorded for the first time. Moreover, the analysis of characters of three species of Chondrophycus previously known from the Mediterranean Sea (C. patentirameus (Montagne) K.W. Nam, C. tenerrimus (Cremades) G. Furnari et al. and C. thuyoides (Kutzing) G. Furnari) led us to conclude that they belong to the genus Palisada. The following new combinations are formally proposed: P. patentiramea (Montagne) Serio et al., P. thuyoides (Kutzing) Serio et al., P. tenerrima (Cremades) Serio et al.

Questo libro contiene una chiave dicotomica per l'identificazione delle alghe marine piu' comuni dell'Alto Adriatico, basata su caratteri di facile osservazione e quindi relativamente accessibile per principianti. Le 113 schede illustrate, con la descrizione molrfologica e la distribuzione dei taxa, includono piu' della meta' dell'intera flora marina del Golfo di Trieste. L'introduzione illustra sinteticamente le principali caratteristiche ambientali del Golfo di Trieste e spiega i principali caratteri utilizzati nella chiave per il riconoscimento delle alghe. L'appendice comprende il glossario dei termini scientifici utilizzati nel testo. La guida è consigliata ai seawatcher che visitano l'Area Marina Protetta di Miramare dove sono state scattate parte delle immagini.

The new species Ulva ardreana is here proposed to replace Ulva bifrons, an invalid name because no holotype was designated in the protologue. The new species consists of two to three distromatic blades arising from a short stipe, and it is easily distinguished from the other blade-like Ulva species in having a remarkable diversity in both shape and size of cells in the two layers.

Results are presented of a study of 15 specimens on six herbarium sheets in the Queensland Herbarium, Indooroopilly, Australia (BRI) labelled as L. pedicularioides Borgesen v. queenslandica Cribb (Ceramiales, Rhodophyta), including the lectotype. All specimens, except the lectotype, belong to species of Chondrophycus or Laurencia either previously recorded or described from Australia, including C. succisus (Cribb) K. W. Nam, L. brongniartii J. Agardh, L. distichophylla J. Agardh, L. heteroclada Harvey and L. majuscula (Harvey) Lucas. Only the lectotype, a sterile specimen collected at Redcliffe (Queensland, Australia), exhibits those vegetative features consistent with L. pedicularioides v. queenslandica. From comparisons with the holotype of L. pedicularioides Borgesen, a tetrasporic specimen collected at Dwarka (India) housed in the herbarium of Copenhagen (C), it is confirmed that Cribb's variety belongs in Borgesen's species. Moreover, due to the epidermal origin of tetrasporangia observed in the holotype, this species is transferred to Osmundea as 0. pedicularioides (Borgesen) comb. nov. This first record from both the Indian and the SW-Pacific Oceans of a species of Osmundea, suggests that the genus might reflect a Tethyan (and not a late Tethyan) distribution pattern.

A study was carried out to determine the status and disposition of Corallinaceae recorded from the Ross Sea (Antarctica), viz. Clathromorphum lemoineanum, Leptophytum coulmanicum, L. laeve and L. foecundum. A re-examination of the type of Lithothamnion coulmanicum (basionym of Leptophytum coulmanicum) showed that it is referable to the genus Phymatolithon because it possesses epithallial cells whose outermost walls are rounded to flattened and meristem cells that are as short as or shorter than their immediate inward derivatives. Such characters were also evident in specimens from McMurdo Sound. Moreover, because all the specimens studied had a conceptacle chamber roof c. 300 μm in diameter, a thallus thickness of up to 1 mm, and buried old conceptacles, they are conspecific with P. foecundum. Studies of specimens from Terra Nova Bay identified as C. lemoineanum and of specimens from Franklin Island identified as L. laeve showed that they should all be referred to P. foecundum. Furthermore, judging by the description and illustrations given by Zaneveld & Sanford [Blumea 26: 205-231 (1980)], records of P. foecundum (as L. foecundum) from Cape Hallett and Moubray Bay can be confirmed. Therefore, P. foecundum is the only member of Corallinaceae confirmed to occur in the Ross Sea (Antarctica).

Feldmann (1970: 249), quoting the results of Hustede (1960), who had shown that Bryopsis halymeniae Berthold (1882: 497) was the gametophyte of a Derbesia sp. [1] , pointed out that this species could not belong to the genus Bryopsis differing from it in chloroplasts with no pyrenoids and gametes without a stigma. On that basis, as well as because of its peculiar life cycle, he stated that Bryopsis halymeniae should be considered the type of a new genus: Bryopsidella . Even though Feldmann (1970) did not explicitely propose the new combination Bryopsidella halymeniae , such a binomial was reported by Gallardo et al . (1993: 412, note 60) and by Boudouresque & Per-ret-Boudoure-sque (1987: 83). [1] A more complete paper showing that Derbesia neglecta and Bryopsis halymeniae are phases of one species, was later published by Hustede (1964).

Attention is called to Ulvaceae invalidly described by Bliding in 1960 and 1963, due to his failure to indicate Types. The following new taxa Ulva croatica, Ulva mediterranea, Ulva splitiana, Ulva flexuosa var. linziformis, Ulva linzoides, Ulva blidingii, Ulva flexuosa [subsp. paradoxa] var. profunda and Ulva prolifera subsp. blidingiana to replace the invalid names Enteromorpha adriatica, Enteromorpha aragoensis, Enteromorpha jugoslavica, Enteromorpha linziformis, Enteromorpha stipitata var. linzoides, Ulva neapolitana, Enteromorpha flexuosa [subsp. paradoxa] var. profunda and Enteromorpha prolifera subsp. gullmariensis respectively, are proposed. Moreover, the conspecificity between Enteromorpha multiramosa Bliding nom. inval. (= Ulva multiramosa Taskin) and Ulva polyclada Kraft is proposed.

Recent taxonomic studies of the genus Laurencia sensu lato (Ceramiales, Rhodomelaceae) have resulted in the recognition of three genera within the ‘Laurencia complex’: Laurencia sensu stricto, Chondrophycus and Osmundea. A critical examination of all Mediterranean records of taxa referred to Laurencia has shown that three species of Chondrophycus, six species of Osmundea and nine species of Laurencia are present. These taxa are described and illustrated. Laurencia caduciramulosa and L. intricata are reported for the first time from the Mediterranean Sea and from Italy, respectively. A key to the Mediterranean species of the Laurencia complex is given.

The red algae Chondrophycus patentirameus (Montagne) Nam (‘patentiramea’) and L. paniculata (C. Agardh) J. Agardh were investigated on the basis of type material and recent collections. Both species show the following features: (i) production of two vegetative pericentral cells from each axial segment; (ii) absence of secondary pit connections between cortical cells; (iii) lack of projecting cortical cells near the apex; (iv) absence of lenticular thickenings in the walls of medullary cells; and (v) perpendicular arrangement of tetrasporangia, each of which is produced from the second pericentral cell in each fertile segment with no additional tetrasporangial pericentral cells. However, C. patentirameus has a stoloniferous holdfast, divaricate branching (with branches arising at angles up to 90°) and non-palisade-like superficial cortical cells, whereas L. paniculata has a discoid holdfast, non-divaricate branching and a palisade-like cortical layer. From this study it is concluded that C. patentirameus (...

Osmundea maggsiana Serio, Cormaci et G. Furnari sp. nov. (Ceramjales, Rhodophyta) is described from the Mediterranean Sea. Thalli are terete, rigid in texture, and irregularly ramified and have as many as three orders of branching. Branches and branchlets are irregularly alternate to spirally (seldom suboppositely) arranged. Epidermal cells do not protrude at the ends of branchlets and have no secondary pit connections; in transverse section they are radially elongate and palisadelike. Vegetative axial segments have two pericentral cells. Tetrasporangia, produced from epidermal cells, are cut off laterally from the mother cells. The two cover cells are aligned parallel to the stichidial axis in surface view. Male gametophytes have reproductive structures of the ‘filament’ type. Spermatangial branches are simple, terminating in one or two (rarely three) spherical sterile cells and are inserted in cuplike depressions located at the bifurcation of branchlets. The new species resembles Osmundea hybri...

A study of the morphology of the brown alga Cystoseira susanensis , a species known only from the type locality (Susa, Lybia) and from southeastern Sicily, was carried out on numerous thalli occurring in littoral rockpools at Marzamemi (Syracuse, Italy). The species has a short primary axis bearing numerous secondary axes close to the base. Such a branching pattern probably led Nizamuddin to consider his species as caespitose, while, on the contrary, it is not caespitose. Observations in culture of the first phases of segmentation of zygotes as well as of the first growth stages of germlings are also provided.

The original collections of Cystoseira algeriensis J. Feldmann and of Cystoseira elegans Sauvageau, both held in the Herbarium of the Laboratoire de Cryptogamie, Museum National d'Histoire Naturelle (PC), were examined and lectotypes were designated, since no holotypes were indicated by original authors.

A new species of the genus Polysiphonia from the Mediterranean Sea is described. It is an ecorticate species, with 4 pericentral cells, showing prostrate axes from which erect axes arise. Rhizoids are formed by pericentral cells in a median position remaining in open connection with them. Erect axes are straight, simple throughout or pseudodichotomous at the base then simple or with one (rarely two-three) orders of branching; trichoblasts and scar cells not observed. Only tetrasporangial plants were found. They show ellipsoid tetrasporangia borne in short straight series, often interrupted by sterile segments. The new species is also characterized by a peculiar habit consisting of prostrate axes, adhering to lower faces of Peyssonnelia spp. by means of rhizoids growing upward, from which erect upright axes perforating thalli of the supporting species arise. A comparison with the related species of Polysiphonia was also carried out.

A study of Mediterranean specimens identified as Pseudolithophyllum expansum, Lithophyllum expansum sensu Lemoine and Pseudolithophyllum cabiochiae have shown that the taxa represent the same species and the names (except P. expansum, which is a heterotypic synonym of Mesophyllum lichenoides) represent heterotypic synonyms of Melobesia frondosa, previously treated as a synonym of Lithophyllum grandiusculum, and here considered as a distinct species, Lithophyllum frondosum. All specimens have tetrasporangial conceptacles with a diameter greater than 300 μm, and pore canals that narrow towards the top, with the cells adjacent to them oriented more or less obliquely to the roof surface and projecting into, but not completely occluding, the canal. The above characters are shown also by L. bermudense, which is here considered as a further heterotypic synonym of L. frondosum.

News on both the structure and the periodism of the communities with Cystoseira from the Mediterranean Sea based on literature data, are presented. In order to a better knowledge of such communities, the opportunity of a standardized methodology based on a preliminary study of the qualitative minimal area, on monthly samples to be carried out throughout a year as well as on observations on the vertical distribution of species within the community, is suggested.

Anotrichium tenue (C. Agardh) Nageli is widely distributed in the Mediterranean Sea. It has also been reported from warm waters of the Atlantic, Pacific, and Indian oceans. The species, originally described as Griffithsia tenuis C. Agardh from sterile specimens collected at Venice (Adriatic Sea), was reported from the same area by Zanardini (1841: 171). The main vegetative characters which distinguish A. tenue from related species are the sparse subsecund branching and the origin of branches from the lower ends of cells, as pointed out by Harvey (1858: 130) who examined an "authentic" specimen of "Agardh's G. tenuis from the Mediterranean". Nageli (1862: 397) assigned Griffithsia tenuis to his new genus Anotrichium, which differs from Griffithsia C. Agardh in having tetrasporangia and spermatangia borne singly on basal cells and not in fascicles. He divided Anotrichium, in turn, into two subgenera: A. subg. Anotrichium ("Euanotrichium"), comprising the single species A. barbatum (C. Agardh) Nageli, with a tetrasporangium borne at the distal end of the basal cell of a whorled branch, and A. subg. Coryphosporium Nageli, comprising the single species A. tenue, for which he described the tetrasporangia as being borne terminally on unicellular whorled pedicels. Hauck (1885: 91) described similar tetrasporangia in specimens from the Adriatic Sea. Neither author mentioned the number of sporangia per node. Feldmann-Mazoyer (1941: 411) gave a detailed description of a tetrasporangial specimen from Algeria (western Mediterranean), pointing out that sporangia are borne terminally on pedicels, with 5 to 8 pedicels in each whorl. The same tetrasporangial disposition (Fig. 1-2) is apparent in subsequent reports of this species

A new species of the genus Taonia (Dictyotales, Phaeophyta) is described from the Mediterranean Sea. The species is characterized by pseudodichotomous fronds having entire margins and by a pronounced differentiation between the medullary and cortical cells throughout the thallus. Only tetrasporangial plants were found. The species differs from T. atomaria f. ciliata in having differently sized cells in cross section and an entire margin and from T. lennebackerae in both the habit and in the shape of cells in longitudinal section.

Observations on three interesting Ceramiales from the Mediterranean Sea are reported; Ceramium incospicuum Zanardini, Polysiphonia setacea Hollenberg and Rodriguezella pinnata (Kutzing) Schmitz ex Falkenberg. The male reproductive structures on the genus Rodriguezella are described for the first time.

All seagrass species known from the Mediterranean basin have been recorded along the Sicilian coast, where studies have been carried out at a very local scale and information is fragmented or confined to the grey literature. The objective of this article is to summarise and evaluate current knowledge on seagrass species on the Sicilian coasts, providing an overview of species distribution, genetic diversity, biology and ecology, based on the literature and unpublished data. Most literature studies have been carried out on Posidonia oceanica meadows because of their wide distribution, complexity and ecological importance. In this study, the analyses carried out on P. oceanica structural and functional features show that the Sicilian meadows are in good condition with respect to the Mediterranean average, probably because of relatively low anthropogenic pressure and favourable ecological conditions. The available data on this species summarised in this article represent an important starting point from which to build effective plans for understanding levels of environmental threats and for supporting conservation strategies for these important ecosystems. Conversely, the limited information available on other seagrasses only allows the description of some structural and functional features, and does not permit to drive overall conclusions on their general health status.

This article gives a picture of recent studies on the phytobenthos of Sicily, paying particular attention to research carried out in the last 10–15 years. Twenty new taxa have been described from Sicily, and floristic studies have recorded 823 taxa at the specific and infraspecific levels. Vegetational studies have been used to verify changes that have possibly occurred in Sicilian areas over the last 30 years. Particular attention was also paid to 22 taxa considered to have been introduced into the Mediterranean Sea and which are found along the Sicilian coast. Applied research dealt mainly with management of the territory, promotion of a sustainable development model for the coastal zone, and using macroalgal communities to assess the quality of Sicilian waters. Finally, some suggestions for studies that should be carried out to increase phytobenthic knowledge of Sicilian coastal waters are made.

A new species, Chylocladia wynnei sp. nov., is described from the Mediterranean Sea. It consists of 2–4 terete, unbranched erect axes, 5–10(–13) mm high, arising from a discoid holdfast. Axes, covered by a thick mucilaginous layer, are hollow throughout. They are divided into segments by monostromatic diaphragms and are constricted at the diaphragms. Axes have a unilayered cortex and longitudinal filaments lining their inner surface; gland cells are cut off from these filaments. Gametophytic plants are dioecious and consist of only two segments. Male thalli have spermatangia in superficial sori located between the two segments. One or two spherical sessile cystocarps are borne on the distal part of the basal segment. Tetrasporic plants comprise 4–5 segments; tetrahedrally divided tetrasporangia are scattered throughout the thallus. These sporangia are transformed from larger cortical cells and, when mature, they protrude into the thallus cavity. Diminutive stature and unbranched erect axes covered with a thick mucilaginous layer clearly distinguish C. wynnei from previously described species of Chylocladia.

SUMMARY We describe Verosphacela silvae sp. nov., from the Mediterranean Sea. It consists of horizontal filaments living on the lower face of the red alga Peyssonnelia rubra (Greville) J. Agardh, from which erect filaments up to 1.5 mm high rise and grow upright after passing through the thallus of the supporting species. There are both horizontal and erect filaments growing by apical cells. In the subapical cells, 1–2 longitudinal divisions occur (more frequently in the erect filaments) but no secondary transverse divisions occur. Erect filaments bear lateral propagules on a stalk of one to three (rarely more) cells. Propagules, with neither apical cells nor arms, consist of seven cells. Zoidangia are borne at the apex of erect laterals. The new species differs from V. ebrachia Henry mainly in habit, propagules and zoidangia. In addition, distinct from V. ebrachia, filaments of V. silvae never penetrate between the cuticle and the cell wall of the supporting alga. Moreover, propagules of V. silvae consist of seven cells, whereas those of V. ebrachia consist of 9–13 cells, and zoidangia are terminal on laterals in V. silvae, whereas in V. ebrachia they are sessile on both axes and laterals.

A study of the morphology of the brown alga Cystoseira squarrosa De Notaris, a rare and little known species, was carried out on numerous thalli collected at Torre del Serpe near Otranto (Apulia, Italy). Because the original material of this species, held in the Herbarium of the University of Genova (GE), was destroyed during the Second World War, a neotype is designed here. The species is well characterized by the combination of the following characters: not caespitose, bush-like habit; short primary axis bearing 1-2 secondary axes inserted at right angle; oblong and warty tophules; slightly prominent and smooth apex of the axes; robust, rigid, flattened, not spaced spinose appendages with bifid, trifid or multifid apices and conceptacles grouped at the base of the spinose appendages.

An annotated checklist of the Ceramiales (Rhodophyceae; red algae) of the Mediterranean, based on literature records, is given. The distribution of each taxon in the area (which is divided into 16 regions) is reported. The number of species and infraspecific taxa of this group accepted for the Mediterranean Sea as currently recognised taxonomically is 271. This list has benefited from the suggestions on taxonomy, nomenclature and regional distribution made by phycological advisers for each region.

Erratum to: Biol Invasions DOI 10.1007/s10530-010-9803-y

This is the first record of Botryocladia madagascariensis from the Gulf of Antalya (Mediterranean Turkish coast). A description of the specimens collected as well as a key to the identification of Mediterranean species of the genus Botryocladia are also included. Some considerations on the distribution of B. madagascariensis, with reference to that of the related species B. botryoides, are also made.

The results of a study on the benthic macroalgal flora and vegetation of Terra Nova Bay (Ross Sea) are presented for the years 1987–88 and 1989–90. The flora is rather poor (nine Rhodophyceae, four Fucophyceae,four Chlorophyceae), but richer than that known from adjacent areas. The vegetation is on the whole characterized by a prevalence of shade-adapted species among which Iridaea cordata, Phyllophora antarctica and Clathromorphum lemoineanum dominated in the upper infralittoral, lower infralittoral and circalittoral zones, respectively. Moreover, we report on the results of a study, carried out in the years 1993–94, on the biomass of Iridaea cordata and Phyllophora antarctica, which represent the most important primary producers among the macroalgae of the Ross Sea.

During the last two decades, the benthic algal flora of the northern Adriatic Sea has changed as a result of increased pollution by sewage, agricultural drainage and industrial discharges. In order to verify if pollution has also influenced the benthic algal flora of the southern Adriatic, a study was undertaken of the Tremiti Islands and the results compared with previously published floristic data of the area. The results indicate changes in the benthic flora. Although the total number of species had increased slightly (301 species compared with 265 from the literature), the floristic composition was quite different, with 109 species not now found and 145 species new to the area. Since several sensitive species, like Cystoseira spp. and Sargassum spp., had disappeared and a greater number of opportunistic species was recorded, it can be concluded that the southern Adriatic is nowadays also influenced by pollution impact.

Results of a seasonal study on biomass in an infralittoral population of Iridaea cordata from Terra Nova Bay (Ross Sea, Antarctica) are reported.Thalli were collected during the IX Italian Antarctic Expedition (austral summer 1993–94). The population studied is that living at depths of 4 to 6 m, where the highest density of plants occurred. The highest value of biomass (wet weight 3440 g m-2) was found at the beginning of summer. In that period 72.5% of biomass was from 128 specimens belonging to weight classes 8 (>16 to 32 g) to 10 (>64 g), corresponding to 13.4% of the population in numbers. Small ( 8 to 16 g) to 9 (>32 to 64 g), which numerically represented 18.5% of the population. Data showed that biomass depended mainly on the presence of large heavy specimens, even though they were always few in number. Moreover, the occurrence of such large thalli at the beginning of summer suggests that Iridaea cordata continues to grow during the long antarctic winter.

A check-list of Mediterranean green algae, based on literature records, is given. The distribution of each taxon in the area (which is divided into 16 regions) is reported. The number of species and intraspecific taxa accepted for the Mediterranean Sea under current taxonomy is 214. This list has benefited from the suggestions on taxonomy, nomenclature and regional distribution made by phycological advisers for each region

A new species of the genus Hypnea Lamouroux, H. furnariana sp. nov., from the eastern coast of Sicily (Mediterranean Sea) is described. Plants form entangled mats with anastomosing branches. Branches and branchlets are subulate and much more slender than the main axes. In transverse section the axial cells are very small, while pericentral cells are quite larger and rounded or slightly oblong-shaped. Tetraspo-rangial swellings (annular or unilaterally exserted) and cystocarps are localized in the sub-apical or in the middle part of fertile branches. A comparison was made with the closely related species H. spinella and H. pannosa.

The authors report the results of a floristic study of the benthic macroalgae from Terra Nova Bay (Ross Sea, Antarctica) based on collections made during two Italian expeditions to Antarctica. A brief description, phytogeographic data and, where necessary, taxonomic and nomenclatural observations are given for the 17 taxa encountered (9 Rhodophyceae, 4 Fucophyceae and 4 Chlorophyceae)

A check-list of Mediterranean brown algae, based on literature records, is given. The distribution of each taxon in the area (which is divided into 16 regions) is reported. The number of taxa accepted for the Mediterranean Sea under current taxonomy is 265. This list has benefited from the suggestions on taxonomy, nomenclature and regional distribution made by algological advisers from each region

The authors report on the occurrence in Sicily of three Florideophyceae newly recorded for the Mediterranean Sea: Botryocladia madagascariensis G. Feldmann, Ceramium strobiliforme Lawson et John and Chondria pygmaea Garbary et Vandermeulen. A brief description as well as ecological and phytogeographic data are provided for each species

The question of whether or not Leptophytum (Corallinaceae, Rhodophyta) should be recognised as a distinct genus has been addressed using new data generated from type and other specimens combined with analyses of previously published data from various authors. The results have shown that none of the criteria proposed to separate Leptophytum from Phymatolithon are reliable at generic level. Some lead to the exclusion of type species from genera, others are impossible to assess because information is lacking for virtually all included species, others have character states that intergrade and thus are unsuitable and still others appear to be useful for separating species but not genera. Most of the character states proposed as diagnostic of Leptophytum are unknown or are not present in most of the species that were explicitly included in the recent proposed re-instatement of the genus and, in some cases, species included in Leptophytum show the opposing character state for Phymatolithon. No serious conflict occurs between the holotype fragments of Leptophytum laeve (the type species of Leptophytum) and the designated epitype and the designation of an epitype is fully justified because all of the characters evident in the holotype are demonstrably ambiguous and could apply to more than one species. Moreover, new evidence supports the probable conspecificity of the holotype and the designated epitype and reinforces the conclusion that Leptophytum should not be recognised as a genus distinct from Phymatolithon. Nomenclaturally, the correct authorship of the name of the type species of Leptophytum is L. laeve Adey and not L. laeve (Str�mfelt) Adey or L. laeve (Foslie in Rosenvinge) Adey, and for purposes of priority, the name Leptophytum laeve dates from 1966.

Specimens of Antithamnionella elegans (Berthold) Cormaci et Furnari (Ceramiaceae, Rhodophyta) with an undescribed arrangement of whorl-branchlets (opposite and decussate) are recorded from the Mediterranean Sea. Comparisons of Antithamnionella elegans with Antithamnion sublittorale Setchell et Gardner and Antithamnionella breviramosa (Dawson) Wollaston ex Womersley et Bailey showed that these taxa are conspecific. The only significant difference among these taxa involves the arrangement of the whorl-branchlets; this is not considered sufficient to separate them as species, but only as varieties. The following varieties are proposed: Antithamnionella elegans v. elegans (syn. A. breviramosa), with usually three whorl-branchlets per whorl; A. elegans v. sublittoralis (Setchell et Gardner) comb. et stat. nov., with two distichous whorl-branchlets; A. elegans v. decussata var. nov., with two whorl-branchlets decussately arranged; A. elegans v. boergesenii var. nov., with four to five whorl-branchlets ...

The authors point out the presence near Augusta (Siracusa, Sicily) of fertile tetrasporophytes of Cottoniella filamentosa (Howe) Boergesen var. algeriensis (Schotter) Womersley and Shepley (Ceramiales, Rhodomelaceae, Sarcomenioideae). Tetrasporocysts, tetrahedrally divided, lie in two parallel rows in branches of indefinite growth. They are produced by the two lateral pericentral cells of each axial cell. Some taxonomic reflections and a key to the species of Cottoniella complete this work.