Benthic Red Algae Research Articles

The red alga Hildenbrandia rivularis is a weak indicator of the good ecological status of riverine habitats

Our knowledge about the size of benthic red alga populations inhabiting European freshwater ecosystems is still insufficient. For many years, in Europe, Hildenbrandia rivularis (Rhodophyta, Hildenbrandiaceae) was believed to be a very rare species of crustaceous red algae, valuable for oligotrophic system biomonitoring. In this paper, we challenge this assumption and show the phenomenon of H. rivularis expansion (i.e., from mountains and highlands to lowlands) in Europe based on detailed data from Poland. We collected over 311 records of H. rivularis occurring in rivers, streams and lakes (not typical habitats for this alga) across the country, including historical data. Here, we show the detailed distribution of this endangered species in Poland, one of the largest European countries. To examine the mechanism of H. rivularis population expansion, physicochemical data from 122 aquatic ecosystems were investigated. A comparison between three subperiods (1860–1944, 1945–1999, and 2000–2019) revealed an increase in the average abundance of the H. rivularis population in the lowlands area. However, the studied species seems to be disappearing in mountain and upland ecosystems. We found altitude and water flow and quality (i.e., alkalinity, oxygenation and biogens) to be the main determinants of H. rivularis occurrence within the study area. The results indicate that this red alga can be described as an expansive species, and its occurrence does not always indicate good water quality and fast water flow. Surprisingly, in contrast to observations from the last century, the population of H. rivularis in Poland currently occurs mainly in habitats with eu- and hypertrophic waters. We point out here that in the zone with temperate climate influence, H. rivularis is no longer an obvious indicator for oligotrophic ecosystems. We suggest that climate warming and eutrophication–reoligotrophication may have contributed to the increased spread of H. rivularis in Europe over recent decades. In addition, we see no reason to classify H. rivularis as an endangered species in Poland. This species most often inhabits anthropogenic water systems and occurs at high abundance in waters with high concentrations of biogens. For these reasons, H. rivularis is more ubiquitous than a cosmopolitan species (i.e., with a wide range of occurrence but associated with only a specific type of habitat and specific environmental parameters). Thus, the value of H. rivularis as a bioindicator for oligotrophic water ecosystems is very low.

High Diversity and Abundance of Foraminifera Associated with Mediterranean Benthic Red Algae Mats

The Mediterranean Sea comprises habitats such as Posidonia oceanica seagrass meadows that exhibit high associated biodiversity of sessile organisms. Recent pilot research indicates that benthic mats formed by the scarcely investigated fleshy red alga Phyllophora crispa also host a high diversity of benthic fauna. Among the key taxa found in these mats in the recent pilot studies are benthic foraminifera that live as epiphytes on the red algae thalli. Knowledge about their abundance and species richness associated with this habitat in relation to reference habitats is missing. We thus carried out a comparative assessment focusing on foraminifera within samples from P. crispa mats and neighboring P. oceanica meadows on five different sampling sites around Giglio Island in the Tuscan Archipelago (Tyrrhenian Sea, Italy). A total of 104 different foraminiferal taxa were identified, of which a total of 85 taxa were found in P. crispa samples (46 exclusively in this habitat). This biodiversity was higher compared to other studies on phytal habitats in the Mediterranean Sea. The number of foraminiferal taxa associated with P. crispa was significantly higher (average 27.5 ± 8.1 taxa) compared to P. oceanica (leaves average 7.0 ± 3.6, shoots average 7.9 ± 3.4 taxa). The abundance of foraminifera (12,000 individuals m−2 surface area of P. crispa mat) was also higher than in the neighboring P. oceanica meadows (7792 individuals m−2 leaf and 8171 individuals m−2 shoot surface area). The most frequently found taxa across habitats were Miniacina miniacea, Lobatula lobatula, and Sejunctella sp. (24%, 20%, and 6% of the total population, respectively). Our results imply that P. crispa mats host an exceptional diversity of associated foraminifera that is even higher than those associated with seagrass meadows. Red algae mats built by P. crispa may thus be considered as potential refuge habitats and biodiversity reservoirs in management and conservation.

Actualización taxonómica de las algas rojas (Rhodophyta) marinas bentónicas del Atlántico mexicano

Antecedentes y Objetivos: Desde las contribuciones de Dreckmann en 1998 y Ortega et al. en 2001, no se han realizado otros trabajos compilatorios para el Atlántico mexicano en los que se consideren modificaciones y actualizaciones taxonómicas para la flora ficológica de la zona. El objetivo de este trabajo fue presentar un listado actualizado de las algas rojas de la costa mexicana del Golfo de México y el Caribe mexicano, en el que se consideran los nuevos registros para la región a partir de los trabajos mencionados hasta la fecha. Métodos: La información de las especies se obtuvo revisando la mayor cantidad de literatura publicada para el área de estudio, desde 2001 a la fecha y algunos registros previos no considerados antes, así como las bases de datos del Herbario Metropolitano UAMIZ. La sinonimia y el estatus nomenclatural de cada nombre, así como el sistema de clasificación utilizado, fueron revisados en AlgaeBase. Resultados clave: Se obtuvo un listado florístico con 451 especies y 13 categorias infraespecificas de algas rojas distribuidas en 4 clases, 23 órdenes, 52 familias y 171 géneros. Para cada especie se menciona su estado nomenclatural actualmente aceptado, su sinonimia y su distribución. Además, se resaltan con un asterisco aquellos registros antiguos (previos al 2002), así como su distribución por ambiente. Conclusiones: El presente listado reveló dos grandes cambios a la previamente conocida flora de las algas rojas de la zona de estudio. El primero de ellos se encuentra en el terreno de la nomenclatura, e implica una modificación a la clasificación de los taxones (familias, géneros, especies). El segundo repercute en el número de especies presentes. Dado lo anterior, es evidente la necesidad de un monitoreo florístico constante a lo largo del litoral del Atlántico mexicano.

Temperature effects on photosynthesis in gametophytic and sporophytic stages of the freshwater red alga Sirodotia delicatula (Rhodophyta, Batrachospermales) under a global warming perspective

SUMMARYThe increase in Earth's global mean temperature due to human influence has become a major concern, with ecological consequences already being reported around the world. In tropical streams, benthic red algae belonging to the order Batrachospermales contribute to a large fraction of the community energy input and play an important role in sustaining autotrophic food webs. The Batrachospermales also have a unique life history, with heteromorphic life stages (gametophytes and sporophytes) occurring seasonally and with distinct ecological roles. Through “in vivo” chlorophyll fluorescence and dissolved oxygen evolution techniques, we evaluated the effects of projected temperature increases of two future scenarios (RCP 4.5 and RCP 8.5) on the photosynthetic response of Sirodotia delicatula gametophytes and sporophytes. In general, both chlorophyll fluorescence and dissolved oxygen showed that the RCP 8.5 scenario could severely jeopardize the photosynthetic performance of the sporophytes during the summer while also providing a stressful physiological situation to the gametophytes. Due to the crucial role of sporophytes in the development of this species, results indicate that this predicted scenario could affect this species. Given the position of these organisms at the base of the food web in tropical lotic environments, especially in shaded low‐order streams, such impact could generate unforeseen cascade effects on higher trophic levels.

The Significance of New Records of Benthic Red Algae (Rhodophyta) for Hainan Island (and China) between 1990 and 2016

We present an annotated list of new finds of red algae from Hainan Island, Southern China, including those found in 1990 and 1992 during the German-Chinese expeditions to Hainan Island and in 2008–2016 by Titlyanova, Titlyanov, and Li. Between 1990 and 1992, a total of 64 taxa of red algae were newly recorded for Hainan Island. Of these 15 species were new records for China. During the period 2008–2016, a further 54 taxa were newly recorded for Hainan Island, of which 20 were new records for China. The full list of new taxa includes taxonomic forms, dates, and locales, together with known biogeographical distributions. During both periods, the apparent enrichment of red algal marine flora has occurred in a similar way—mainly at the expense of epiphytes with filamentous, thin-filamentous, and finely branched forms. We believe that the changes in the flora of Hainan Island have been influenced by both anthropogenic and natural factors including in particular exploitation of herbivores, nutrient pollution, and coral bleaching.

Systematic revision of the genus Reinboldiella (Ceramiaceae, Rhodophyta) from Taiwan based on comparative morphology and rbcL sequence analyses, including two new species of Reinboldiella

ABSTRACTThe genus Reinboldiella essentially consists of tiny, membranous blades, epiphytic on benthic red algae, with a wide distribution in the north-western Pacific Ocean (Taiwan, Korea and Japan). In this study, we re-examined the generitype R. schmitziana from Taiwan and neighbouring islands. Two new species of Reinboldiella, R. orientalis sp. nov. and R. taiwanensis sp. nov. are recognized from Taiwan based on comparative morphological studies and molecular analyses of RuBisCO large subunit (rbcL) gene sequences. Reinboldiella orientalis is characterized by its rosette-like appearance, with both erect and prostrate, membranous flat blades whereas R. taiwanensis is distinguishable by mainly consisting of erect, membranous blades with few, short prostrate blades in basal parts of the thalli. Thalli of R. schmitziana also have a rosette-like appearance, but their erect flat blades have cylindrical bases or stipes. The rbcL phylogenetic analyses also support the separation of R.‘schmitziana’ from Taiwan and R. schmitziana from Japan and Korea.

Delimitating cryptic species in the Gracilaria domingensis complex (Gracilariaceae, Rhodophyta) using molecular and morphological data.

Species in the genus Gracilaria that display conspicuously flattened vegetative morphologies are a taxonomically challenging group of marine benthic red algae. This is a result of their species richness, morphological similarity, and broad phenotypic plasticity. Within this group, the Gracilaria domingensis complex is one of the most common, conspicuous, and morphologically variable species along the tropical western Atlantic Ocean. Previous research has identified that members of this complex belong to two distantly related clades. However, despite this increased phylogentic resolution, species delimitations within each of these clades remain unclear. Our study assessed the species diversity within this difficult complex using morphological and molecular data from three genetic markers (cox1, UPA, and rbcL). We additionally applied six single-marker species delimitation methods (SDM: ABGD, GMYCs, GMYCm, SPN, bPTP, and PTP) to rbcL, which were largely in agreement regarding species delimitation. These results, combined with our analysis of morphology, indicate that the G.domingensis complex includes seven distinct species, each of which are not all most closely related: G.cervicornis; a ressurected G.ferox; G.apiculata subsp. apiculata; a new species, Gracilaria baiana sp. nov.; G.intermedia subsp. intermedia; G.venezuelensis; and G.domingensis sensu stricto, which includes the later heterotypic synonym, G.yoneshigueana. Our study demonstrates the value of multipronged strategies, including the use of both molecular and morphological approaches, to decipher cryptic species of red algae.

DNA barcoding of a new record of epi-endophytic green algae Ulvella leptochaete (Ulvellaceae, Chlorophyta) in India.

Epi-endophytic green algae comprise one of the most diverse and phylogenetically primitive groups of green algae and are considered to be ubiquitous in the world's oceans; however, no reports of these algae exist from India. Here we report the serendipitous discovery of Ulvella growing on intertidal green algae Cladophora glomerata and benthic red algae Laurencia obtusa collected from India. DNA barcodes at nuclear ribosomal DNA Internal Transcriber Spacer (nrDNA ITS) 1 and 2 regions for Indian isolates from the west and east coasts have been generated for the first time. Based on morphology and DNA barcoding, isolates were identified as Ulvella leptochaete. Phylogenetic reconstruction of concatenated dataset using Maximum Likelihood method differentiated Indian isolates from other accessions of this alga available in Genbank, albeit with low bootstrap support. Monophyly of Ulvella leptochaete was obvious in both of our phylogenetic analyses. With this first report of epi-endophytic algae from Indian territorial waters, the dire need to catalogue its cryptic diversity is highlighted and avenues of future research are discussed.

Phenology, irradiance and temperature characteristics of a freshwater red alga, Nemalionopsis tortuosa (Thoreales), from Kagoshima, southern Japan

SummaryPhenology, irradiance and temperature characteristics of a freshwater benthic red alga, Nemalionopsis tortuosa Yoneda et Yagi (Thoreales), were examined from Kagoshima Prefecture, southern Japan for the conservation of this endemic and endangered species. Field surveys confirmed that algae occurred in shaded habitats from winter to early summer, and disappeared during August through November. A net photosynthesis–irradiance (P–E) model revealed that net photosynthetic rate quickly increased and saturated at low irradiances, where the saturating irradiance (Ek) and compensation irradiance (Ec) were 10 (8–12, 95% credible interval (CRI)) and 8 (6–10, 95% CRI) μmol photon m−2 s−1, respectively. Gross photosynthesis and dark respiration was determined over a range of temperatures (8–36°C) by dissolved oxygen measurements, and revealed that the maximum gross photosynthetic rate was highest at 29.5 (27.4–32.0, 95%CRI) °C. Dark respiration also increased linearly when temperature increased from 8°C to 36°C, indicating that the increase in dark respiration at higher temperature most likely caused decreases in net photosynthesis. The maximum quantum yield (Fv/Fm) that was determined using a pulse amplitude modulated‐chlorophyll fluorometer (Imaging‐PAM) was estimated to be 0.51 (0.50–0.52, 95%CRI) and occurred at an optimal temperature of 21.7 (20.1–23.4, 95%CRI) °C. This species can be considered well‐adapted to the relatively low natural irradiance and temperature conditions of the shaded habitat examined in this study. Our findings can be applied to aid in the creation of a nature‐reserve to protect this species.

Evaluating Light Availability, Seagrass Biomass, and Productivity Using Hyperspectral Airborne Remote Sensing in Saint Joseph’s Bay, Florida

Seagrasses provide a number of critical ecosystem services, including habitat for numerous species, sediment stabilization, and shoreline protection. Ariel photography is a useful tool to estimate the areal extent of seagrasses, but recent innovations in radiometrically calibrated sensors and algorithm development have allowed identification of benthic types and retrieval of absolute density. This study demonstrates the quantitative ability of a high spatial resolution (1 m) airborne hyperspectral sensor (3.2 nm bandwidth) in the complex coastal waters of Saint Joseph’s Bay (SJB). Several benthic types were distinguished, including submerged and floating aquatic vegetation, benthic red algae, bare sand, and optically deep water. A total of 23.6 km2 of benthic vegetation was detected, indicating no dramatic change in vegetation area over the past 30 years. SJB supported high seagrass density at depths shallower than 2 m with an average leaf area index of 2.0 ± 0.6 m2 m−2. Annual seagrass production in the bay was 13,570 t C year−1 and represented 41 % of total marine primary production. The effects of coarser spatial resolution were investigated and found to reduce biomass retrievals, underestimate productivity, and alter patch size statistics. Although data requirements for this approach are considerable, water column optical modeling may reduce the in situ requirements and facilitate the transition of this technique to routine monitoring efforts. The ability to quantify not just areal extent but also productivity of a seagrass meadow in optically complex coastal waters can provide information on the capacity of these environments to support marine food webs.

Marine Red Algae from the North Coast of Papua New Guinea

The marine benthic red algae of the north coast of Papua New Guinea are documented, and 27 of the 151 + species are illustrated. All taxa are listed with bibliographic, taxonomic, and biogeographic comments. Only two species are based on type specimens collected from Papua New Guinea (Halymenia durvillei and Chrysymenia kaernbachii). Apart from several new taxa identified in the collections, there are no endemic species known from these shores. As a result of this survey, Laurencia columellaris Børgesen is transferred to the genus Chondrophycus, and Eupogodon palmatifidus is transfered to the genus Dasya. The discovery of the Caribbean genus Rhodogorgon constitutes a major range extension as does that of the North Atlantic Nitophyllum punctatum. The deep-water alga Renouxia, also known from the south coast of Papua New Guinea, is now reported from the north coast, and Polysiphonia polyphysa is recorded for the first time since its discovery and description in the 1850s. The marine red algal flora appears to reflect a typical tropical western Pacific component.

Studies on R-phycoerythrins from two Antarctic marine red algae and a mesophilic red alga

R-phycoerythrin was purified from two benthic red algae, Iridaea cordata and Phyllophora antarctica, obtained growing at −2°C under thick sea ice off the coast of Antarctica. For the I. cordata protein, the molecular mass was 245,000 Da, and its secondary structure was 60% α helix, 17% β sheet, 16% turn, and 7% other. The light-harvesting faculties of the I. cordata protein resembled those of R-phycoerythrins from mesophilic red algae and were distinctive from the novel R-phycoerythrin from P. antarctica. Deconvolution of the visible absorption spectrum of R-phycoerythrin from I. cordata indicated a minimum of five component bands having maxima at 568, 558, 534, 496, and 481 nm. R-phycoerythrins from the mesophilic Porphyra tenera and psychrophilic Phyllophora antarctica had the same five bands. The protein from Phyllophora antarctica obtained its unique spectrum from a more intense component at 482 nm, and a less intense band at 533 nm. This change was probably produced by a replacement of phycoerythrobilin by phycourobilin. A temperature study of the circular dichroism CD was obtained for R-phycoerythrin from I. cordata from 4 to 80°C. Laser time-resolved fluorescence studies on R-phycoerythrin showed bilin to bilin energy transfer with a 60.2-ps lifetime, which should occur by the Forster resonance. The similarities in spectra between the proteins from I. cordata and Porphyra tenera and the different spectrum for the protein from Phyllophora antarctica show that only particular antarctic habitats require unique R-phycoerythrins.

Annotated and illustrated survey of the marine macroalgae from Motupore Island and vicinity (Port Moresby area, Papua New Guinea). III. Rhodophyta

The marine benthic red algae of Motupore Island and vicinity (Port Moresby area, Papua New Guinea [PNG]) are documented and 36 of the 161 species are illustrated. All records are listed with bibliographic, biogeographic, taxonomic and nomenclatural comments. Apart from several undescribed taxa, which we are in the process of describing separately, none is endemic to the island at this stage. The discovery of the east Australian species Gracilaria rhodymenioides represents a substantial range extension as does Ceramium lentiforme from New South Wales. One species of Gibsmithia also represents a significant range extension from its Lord Howe Island, Norfolk Island and southern Great Barrier Reef distributions. Platoma ardreanum is reported from outside its Hawaiian distribution for the first time, and the Caribbean Renouxia antillana represents a major range extension for the Pacific. Forty-four species appear to be newly recorded for the PNG marine flora and 108 are new records for the Island itself. Because all collections were taken during the month of July, many seasonal entities may be missing from this list and the total marine flora is not yet known. Moreover, because previous records are quite detailed with respect to epiphytic and turf algae, we have not concentrated on these species. The non-geniculate coralline algae have only been collected sporadically as part of this survey.

Genetic variation within and among North Atlantic and Baltic populations of the benthic algaPhycodrys rubens(Rhodophyta)

Genetic variation was examined within and among North Atlantic, North Sea and Baltic populations of the benthic red alga Phycodrys rubens using allozymes and random amplified polymorphic DNA (RAPD) markers. On western and eastern North Atlantic coasts distinct allozyme types were found, with the exception of western Newfoundland where East and West Atlantic types co-occur. Along the European coasts, two genetic groups were distinguished by fixed allelic differences: an outer oceanic group and a North Sea/Baltic group. The two genetic types co-occur in the Skagerrak and Kattegat region. Reproductive isolation between the two types is suggested by the lack of hybrids in the overlap zones, and they may therefore represent sibling species. Unexpectedly an analysis of RAPD variation was unable to recover the two cryptic species identified using allozymes. Within-population RAPD variation was similar to or greater than between-population variation. The lack of structure in the RAPD data cannot be attributed solely to technical artefacts of the method but appears to reflect real biological variability. Within-population genomic polymorphisms caused by frequent mutational events are discussed, as are high amounts of genetic drift and possible disruptive selection brought about by stressed habitats. Finally, Baltic and extra-Baltic salinity ecotypes are known to exist in P, rubens. However, no correlation between ecotypic variation and allozyme groups was detected.

Multiple trans-Arctic passages in the red alga Phycodrys rubens: evidence from nuclear rDNA ITS sequences

In order to investigate how episodes of geological and climatic change have influenced the distribution and evolutionary diversification of Arctic to cold temperate-North Atlantic seaweed species, intraspecific genetic variation was analyzed among isolates of the sublittoral, benthic red alga Phycodrys rubens (collected between June 1992 and January 1994). Rooted phylogenetic analyses of nuclear ribosomal DNA internal transcribed spacer (ITS) sequences and the plastid encoded Rubisco spacer sequences suggest that P. rubens invaded the North Atlantic from the Pacific shortly after the opening of the Bering Strait (3 to 3.5 million years ago), colonizing both the western and eastern Atlantic coasts. Based on these data we further hypothesize that P. rubens survived along the European coasts during the more recent Pleistocene glaciations, while becoming locally extinct along the North American Atlantic coasts. Following retraction of the last ice sheet, the western Atlantic coast was colonized a second time from the Pacific. The presence of two distinct genetic types (based on ITS and Rubisco sequences) along the European coasts is postulated to be a result of isolation and subsequent differentiation. This is likely because ice-free areas are known to have existed in northern Scotland and Norway during the last glaciation. The presence of an East Atlantic genetic type along the West Atlantic coast is believed to be a recent introduction (caused by human activity) of P. rubens to Newfoundland.

Point quadrat versus video transect estimates of the cover of benthic red algae

Point quadrat (PQ) and video transect (VT) techniques were compared to determine the feasibility of using the latter to sample subtidal red algal assemblages. More taxa were found by PQs than by VTs, both overall and on a per quadrat basis. VTs tended to overestimate the percent cover of rock and articulated coralline algae. VTs were incapable of resolving many of the less common red algae. Video sampling required less time in the field than point quadrats but laboratory analysis was very time consunling. Lack of resolution and extensive laboratory analysis make this technique insufficient for sampling benthic red algal populations. However, VTs may be useful in documenting large-scale differences between regions, such as the percent cover of understory kelps or the density of large mobile invertebrates in central California kelp forests. Video sampling has been successfully used in the intertidal but traditional, random point quadrats s t d appear to be the most efficient and accurate way to sample benthlc communities in kelp forests. The advent of quantitative techniques to sample subtidal benthic communities has aided the scientific description of pattern and helped transform marine ecology from a wholly observational to a more experimental science. Techniques to measure percent cover were first developed by terrestrial botanists (e.g. Greig-Smith 1983) and have been successfully adapted to subtidal communities by marine ecologists (e.g. Foster 1975, Cowen et al. 1982, Kennelly 1987). Photography has been used quantitatively in intertidal, subtidal and deep-sea habitats (Bohnsack 1979, Budd 1982, Witman & Sebens 1985, Jaap 1986, Rosman & Boland 1986, Thouzeau & Hily 1986, Meulstee et al. 1988, Edmunds & Witman 1991). Due to recent advances in video resolution and ease of use, it has begun to replace traditional photography as both a qualitative (Potts et al. 1987, Semple & Sharp 1988) and quantita' Present address: Graduate Program in Ecology and Evolutionary Biology, Brown University, Providence, Rhode Island 02912, USA tive (Jaap et al. 1990, Maney et al. 1990, Berklemans 1992) sampling tool. The strength of video is its ability to rapidly acquire data and permit analysis in the laboratory at a later date. Video quadrats and transects are now being used routinely to measure the density and percent cover of subtidal marine organisms (e.g. Edmunds & Witman 1991). As part of a study on the effect of light on understory algae in central California (USA) kelp forests, we have been using point quadrats to estimate algal cover. These involve scoring a small number of random points (usually 10 to 20) along a bar randomly placed on the substrate. This technique is excellent for relatively abundant organisms but, theoretically, undersamples rare species because of the few points used. Whorff & Griffing (1992) recently suggested that point quadrats undersample the substrata while Foster et al. (1991) concluded that point quadrats provide better estimates of the total number of taxa and their total and individual percent cover. An alternative to point quadrat methods for rare species are search techniques (e.g. Nybakken 1978, McClanahan 1990, McClanahan & Muthiga 1992). These have been designed for extremely rare species (i.e. approximately 0.1 ind. m-2; McClanahan & Muthiga 1992) but understory algae in many benthic habitats range from 1 to 30% cover (Foster 1975). In this paper, we present results of a direct comparison of point quadrat (PQ) and video transect (VT) sampling for benthic algal assemblages. Video was used over traditional photo-quadrats because video film is significantly cheaper than still film and more samples can be taken between film changes. To test for and alleviate the potential PQ bias of using too few points, we sampled the video image using 5 times as many random points as the PQ. This should have increased the likelihood of detecting rare species. The number of 0 Inter-Research 1993 204 Mar. Ecol. Prog. Ser. 101: 203-208. 1993

Marine red algae of the Coffs Harbour region, northern New South Wales

The marine benthic red algae of the Coffs Harbour region are described and illustrated in detail. The survey constitutes the first ever detailed descriptive and illustrative mainland regional monograph of any area along the entire eastern Australian seaboard. Collections made intertidally and to depths of 20 m have included 119 species in 74 genera, 26 families, and 8 orders of Rhodophyta, of which 54 (45%) were previously unrecorded from eastern Australia, 22 (18%) are new records for the whole of Australia (16 being new Southern Hemisphere records), 1 (Dictyothumnion) constitutes a new genus, and 16 (13%) are new species in the genera Gracilaria, Curdiea, Botryocladia, Dictyothamnion, Antithamnion, Ceramium, Callithumnion, Anotrichium, Nitophyllum, Phycodrys, Apoglossum, Dasya, Fernandosiphonia, and Herposiphonia. Also included are major Australian revisions of the genera Martensia and Nitophyllum, and six new combinations are proposed (Chondria infestans, Curdiea angustata, Dasya pilosa, Haraldiophyllum sinuosum, Myriogramme pulchellum, and Stenograrnme phyllophoroides). The Coffs Harbour flora, although related to the north-eastern and, to a lesser degree, southern Australian floras, has a number of species previously known only from much more remote localities, such as Japan (6 species), California (4 species), New Zealand (3 species), India (2 species), South America (2 species), the Galapagos Islands (1 species), China (1 species), South Africa (1 species), and the Mediterranean (1 species). Twelve of the 22 species newly recorded for Australia show a definite western Pacific distribution, a region with which the overall Coffs Harbour flora has strong affinities.

THE GENUS PLATOMA (GIGARTINALES, RHODOPHYTA) WITH A DESCRIPTION OF P. ABBOTTIANA SP. NOV.1

ABSTRACTPlatoma abbottiana (Gymnophlaeaceae; Gigartinales), a new species of benthic red algae, is described from Isla Mejía and is the second member of this genus reported from the Gulf of California, Mexico. Vegetative anatomy and reproductive details of the carpogonial and auxiliary cell branches of the new species are described and illustrated. Geographical distributions of the seven previously described Platoma species are given. Their distinguishing morphological characteristics are compared to those of the new species. The correct time and place of valid publication of the generic name, Platoma, and some of its binomials are discussed.