Characeae Research Articles

Environmental factors influencing biomass and bulbil production of Nitellopsis obtusa in Lake Koronis, Stearns County, Minnesota

Starry stonewort [Nitellopsis obtusa (Desvaux) J. Groves] is a green macroalga in the family Characeae that is native to Eurasia. In the United States it has invaded many waterbodies across the northern tier from New York to Minnesota. In Minnesota, starry stonewort often grows later into the growing (September to December) season than most native species; however, the environmental factors that influence this life history trait are not well understood. Starry stonewort was harvested every 3 wk from May to November in 2020 and 2021 from four locations in Lake Koronis, Stearns County, MN. Light, water pH, and water temperature were also collected to correlate these variables to starry stonewort growth. Rhizoid biomass had weak negative correlations with temperature (rs ¼ 0.19) and pH (rs ¼ 0.14). Bulbil biomass had weak negative correlations with temperature (rs ¼ 0.24), pH (rs ¼ 0.31), and light transmittance (rs ¼ 0.11). Bulbil density had weak negative correlations with temperature (rs ¼ 0.23), pH (rs ¼ 0.29), and light transmittance (rs ¼ 0.10). Bulbil production was highest between October and November of each year. Bulbil biomass and density was lower in 2020 (4.6 g m2 and 1,229 bulbils m2) thanin2021(14.7gm2 and 5,211 bulbils m2). The average annual bulbil density was 1,537 bulbils m2 and ranged from 0 to 157,000 bulbils m2. The ability of starry stonewort to grow in dense mats and produce large quantities of bulbils contributes to the difficulty of controlling infestations. Bulbils are a method of spatial and temporal distribution that can allow for recolonization of previously treated areas.

Charophytes of Australia’s Northern Territory – II. Tribe Nitelleae

This study of Northern Territory charophytes deals with the tribe Nitelleae in family Characeae. We recognise 16 species of Nitella for the Territory. The list includes seven previously described species (Nitella belangeri, N. biformis, N. congesta, N. heterophylla, N. micklei, N. myriotricha and N. tumulosa, of which N. belangeri and N. tumulosa are newly recorded for the Australian flora), and nine newly described species (N. acanthospora, N. boreali-australis, N. crocodylus, N. limosa, N. martinii, N. nitida, N. oollooensis, N. silicea and N. townsendii). Of the five previously reported Nitella species in the Northern Territory (N. hyalina, N. myriotricha, N. penicillata, N. pseudoflabellata and N. subtilissima), only N. myriotricha is recorded in this study, because the other records were based on erroneous identifications or localities. All Nitella species described here can be distinguished on the basis of their morphology and reproductive arrangement. Keys, illustrations and descriptions of all the species are provided.

Charophytes of Australia’s Northern Territory – I. Tribe Chareae

This study of Northern Territory charophytes documents 22 species in 3 of the genera in tribe Chareae, family Characeae, including 15 previously described species (Chara benthamii, C. erythrogyna, C. globularis, C. karolii, C. lucida, C. porteri, C. protocharoides, C. setosa, C. submollusca, C. wightii, C. zeylanica, Lamprothamnium capitatum, L. compactum, L. stipitatum, Lychnothamnus barbatus) of which 2 are new for the Australian flora (C. erythrogyna and C. wightii), as well as 5 varieties raised to species rank (C. aridicola, C. arnhemensis, C. bancroftii, C. behriana, C. duriuscula), and 2 newly described species (C. lamprothamniformis, C. schultae). Three previously reported species in the tribe (C. braunii, C. corallina, C. fibrosa) are not recorded from the Northern Territory in this study, as previous records were based on erroneous identifications or localities. Although Northern Territory specimens of Lychnothamnus barbatus have not been seen, it has been included in this treatment, because it occurs in south-eastern Queensland, the Gulf of Carpentaria, Papua New Guinea and Timor-Leste. A key, illustrations and descriptions of all the species are provided.

A quantitative method to analyse the sexual development of charophytes (Charophyceae): a baseline for phenological studies

ABSTRACT Traditionally, gametangium morphology has been considered an important feature in the taxonomy of charophytes (family Characeae), although its dimensions change notably with development. We present a methodological approach based on empirical data to describe the development of charophyte sexual organs. This method was tested in Chara hispida, C. aspera and C. canescens from Mediterranean brackish ponds. Five shoots per species and sampling date were collected on 19 dates during 2015 and observed under a stereomicroscope to measure the external diameter of antheridia, and the length and width of oogonia. Gametangial growth adjusted to a logarithmic model (a first period of rapid increase, followed by a slow growth period), with gametangia sizes reaching species-specific maxima. For oogonia, a logarithmic model also described the length-width relationship: a first period of elongation, followed by a swelling process related to ripening. We applied the derivative function to find the point when length and width increased equally. At greater width values (≥420 µm in C. hispida, ≥330 µm in C. aspera, ≥225 µm in C. canescens), width increased faster than length, and oogonia started to swell. Data from a single date, at the most appropriate moment based on the phenology of each species, also provided a good fit and a similar size threshold to distinguish non-swollen from swollen oogonia. This cost-effective method was valid for the three Chara populations, being particularly useful for phenological studies if used in combination with other criteria. We highlight the importance of standardizing these criteria before addressing relevant ecological questions.

On the Morphology of Five Species of <I>Chara</I> (Characeae, Charophyta) from West Bengal, India

Five representatives belonging to the family Characeae have been studied under the genus Chara L. viz., Chara fibrosa C. Agardh ex Bruzelius, Chara socotrensis Nordst., Chara zeylanica Klein ex Willd., Chara vulgaris L. and Chara hydropithys Rchb. occurring in West Bengal. The studies have been done under stereo zoom and Field emission Scanning Electron Microscope (FeSEM). FeSEM observations for the morphology of oospores are the first time in Eastern India. The occurrence of Chara socotrensisis Nordst. reported for the first time from Eastern India.

New Record of Charophytes (Characeae, Charophyta) from Socotra Island, Indian Ocean, Yemen

The charophyte flora from Socotra Island, Indian Ocean, studied for the first time from streams waterbodies that distributed at the northern part of the Island. The recognized charophyte taxa were taxonomically investigated, and four dominant species belonging to family Characeae are identified as Chara braunii, C. globularis, C. hispida and Lamprothamnium papulosum. These taxa are reported as a new record for algal flora of Socotra Island. A brief account of the environment where the charophytes were found is provided, as a first evaluation of the ecological requirements of Indian charophytes. A taxonomically diverse of charophyte assemblage and ecological variables explain abiotic features of biotope as shallow (max 1.3 m), alkaline fresh (pH 7.5–8.4), slightly saline, and moderate eutrophic.

Response of the invasive alga starry stonewort (Nitellopsis obtusa) to control efforts in a Minnesota lake

ABSTRACTGlisson WJ, Wagner CK, McComas SR, Farnum K, Verhoeven MR, Muthukrishnan R, Larkin DJ. 2018. Response of the invasive alga starry stonewort (Nitellopsis obtusa) to control efforts in a Minnesota lake. Lake Reserv Manage. 00:00–00.Starry stonewort (Nitellopsis obtusa), an invasive green macroalga in the family Characeae, has recently been found for the first time in several Midwestern states. This aquatic invasive species is of increasing concern to management agencies, lakeshore property owners, and other stakeholders. Starry stonewort has proven difficult to control, partly due to its ability to reproduce via bulbils (asexual reproductive structures). There has also been a lack of applied research addressing the efficacy of current management practices for controlling starry stonewort. We examined the effects of mechanical and algaecide treatments on starry stonewort biomass, bulbil density, and bulbil viability by monitoring treated areas and untreated reference locations concurrent with management implemented on Lake Koronis in Minnesota. Chelated copper algaecide applications alone and in combination with mechanical harvesting significantly reduced starry stonewort biomass, but algaecide treatment alone failed to reduce the capacity of starry stonewort to regenerate via bulbils. A second, granular algaecide application following an initial treatment with liquid algaecide did not further reduce biomass in any treated area and was associated with a substantial increase in bulbil density in an area treated with algaecide alone. Bulbil viability was greatest in the area treated only with algaecide (86%) and an untreated reference area (84%) and was lowest in an area treated with both mechanical harvest and algaecide (70%). The ability of starry stonewort to regenerate and persist following algaecide treatment is concerning. Multi-pronged management incorporating both chemical and mechanical approaches may improve outcomes of starry stonewort control efforts.

Анализ флоры харальных водорослей (Charales, Charophyta) Украины

Анализ флоры харальных водорослей (Charales, Charophyta) Украины

Первая находка Chara rudis (A. Braun) Leonh. (Charales, Charophyta) в Украине

Первая находка Chara rudis (A. Braun) Leonh. (Charales, Charophyta) в Украине

Chromosome numbers in Australian charophytes (Characeae, Charophyceae)

:Over the course of a 25 year ecological and taxonomic study, the chromosomes of Australian charophytes (family Characeae) were examined and enumerated. The usual number for members of Chara was n = 14 (for dioecious species) or n = 28 (for monoecious species); although Chara braunii has always been recorded as having n = 14 despite being monoecious. Species in sections Agardhia and Grovesia often had higher ploidy levels [n = 3 × 14 (42), n = 4 × 14 (56)]. The usual number for Australian members of Nitella was n = 9 (for dioecous species) and n = 18, 24 or 27 for monoecious species. Nitella stuartii was an exception, having n =15 in the specimens studied here. The usual number for monoecious members of Lamprothamnium was n = 28; although, monoecious Lamprothamnium inflatum consistently had n = 14 (populations from Western Australia, Kangaroo Island and South Australia). Chromosome numbers were different for each species of Tolypella examined (n = 11 to 36). There was a high degree of polyploidy within Characeae, and there was evidence that even the lowest numbers of chromosomes represented polyploids (3n for Nitella and 2n for Chara). Polyploidy and consequent doubling or tripling of enzymatic capacity (via potential multiple isozymes) is likely to have a role in the morphological variability and biochemical flexibility of charophytes. Information about the number and appearance of chromosomes (karyotypes) can be used in systematic studies to determine relatedness of taxa and to understand some of the evolutionary processes operating at the population or species level.

Charophytes (Charales) from Samos and Ikaria (Greece) collected in 2013 and report on some localities in Skiathos (Greece)

Charophytes (Charales) from Samos and Ikaria (Greece) collected in 2013 and report on some localities in Skiathos (Greece)

(2303) Proposal to conserve the name Chara hispida (Characeae) with a conserved type

1 Senckenberg Forschungsinstitut, Senckenberganlage 25, 60325 Frankfurt am Main, Germany 2 Ernst-Moritz-Arndt-Universitat Greifswald, Biologische Station Hiddensee, 18565 Kloster, Germany 3 Borgsheider Weg 11, 45770 Marl, Germany 4 Universitat Rostock, Biowissenschaften, Albert-Einsteinstrasse 3, 18055 Rostock, Germany 5 Banchory, Stirling Acres Road, Kirkcudbright, DG6 4ES, Scotland, U.K. Author for correspondence: Thomas Gregor, thomas.gregor@senckenberg.de

Charophytes (Charales) from Crete (Greece) collected in 2010

Charophytes (Charales) from Crete (Greece) collected in 2010

The genera Chara and Nitella (Chlorophyta, Characeae) in the subtropical Itaipu Reservoir, Brazil

The family Characeae, represented by two genera in Brazil, Chara and Nitella, is considered to include the closest living relatives of land plants, and its members play important ecological role in aquatic ecosystems. The present taxonomic survey of Chara and Nitella was performed in tributaries that join to form the Brazilian shore of the Itaipu Reservoir on the Parana River. Thirteen species were recorded, illustrated, and described: C. braunii var. brasiliensis R.Bicudo, C. guairensis R.Bicudo, N. acuminata A.Braun ex Wallman, N. furcata (Roxburgh ex Bruzileus) C.Agardh, and N. subglomerata A.Braun, already cited for the reservoir, and C. hydropitys Reichenbach, C. rusbyana Howe, N. axillaris A.Braun, N. glaziovii G.Zeller, N. gracilis (Smith) C.Agardh, N. hyalina (DC.) C.Agardh, N. inversa Imahori, and N. microcarpa A.Braun that represent new occurrences for the Itaipu Reservoir and Parana State. Among the species encountered, C. guairensis, N. furcata, and N. glaziovii are widely distributed, while C. hydropitys and C. rusbyana have more restricted distributions.

The genera Chara and Nitella (Chlorophyta, Characeae) in the subtropical Itaipu Reservoir, Brazil

The family Characeae, represented by two genera in Brazil, Chara and Nitella, is considered to include the closest living relatives of land plants, and its members play important ecological role in aquatic ecosystems. The present taxonomic survey of Chara and Nitella was performed in tributaries that join to form the Brazilian shore of the Itaipu Reservoir on the Paraná River. Thirteen species were recorded, illustrated, and described: C. braunii var. brasiliensis R.Bicudo, C. guairensis R.Bicudo, N. acuminata A.Braun ex Wallman, N. furcata (Roxburgh ex Bruzileus) C.Agardh, and N. subglomerata A.Braun, already cited for the reservoir, and C. hydropitys Reichenbach, C. rusbyana Howe, N. axillaris A.Braun, N. glaziovii G.Zeller, N. gracilis (Smith) C.Agardh, N. hyalina (DC.) C.Agardh, N. inversa Imahori, and N. microcarpa A.Braun that represent new occurrences for the Itaipu Reservoir and Paraná State. Among the species encountered, C. guairensis, N. furcata, and N. glaziovii are widely distributed, while C. hydropitys and C. rusbyana have more restricted distributions.

An overview of Nitella (Characeae, Charophyceae) in Australia

The genus Nitella Ag. in algal family Characeae is characterised by furcate (forked) branchlets, compressed oospores (i.e. oval in cross-section), terminal antheridia and a 10-celled coronula on the oogonium. Species of Nitella are submerged plants that grow in a variety of wetland and riverine habitats. Approximately 89 taxa of Nitella (species, subspecies, varieties and forms) have been described on the basis of Australian collections, and published estimates of the number of species range from 18 to >35. The lower value is based on the assumption that infra-specific variation is great, species have a wide distribution, monoecy and dioecy are not indicative of speciation and the number of furcations and the ratio of branchlet segment lengths vary for a species owing to the environment in which they grow. The higher value is based on evidence that morphological characters are relatively constant for a species, that oospore variation is a good indication of speciation and that monoecious and dioecious entities are not inter-fertile. An overview of Australian members of the genus is presented here as a framework for further taxonomic work. Representatives of all three subgenera of Nitella occur in Australia, with subgenus Nitella poorly represented, and subgenera Tieffallenia and Hyella equally speciose. The subgenera are defined here in relation to the Australian taxa they contain. In the present treatment, section Migularia is transferred from subgenus Tieffallenia to subgenus Hyella, and several species are transferred to subgenus Tieffallenia. Within subgenus Tieffallenia, variation in vegetative and oospore morphology is useful for distinguishing among sections and species. However, although members of subgenus Hyella display a similar range of variation in vegetative morphology, most of the species have similar, reticulate, oospore ornamentation. Australia is home to a large number of endemic species of Nitella, many of which are dioecious. The total number of species and the degree of endemism have been underestimated in earlier studies, and it is likely that more than 50 species of Nitella will be recognised on the basis of Australian specimens. A key to the subgenera, and keys to sections in the subgenera are provided.

Phylogeny and evolution of charophytic algae and land plants

Charophytic algae and land plants together make up a monophyletic group, streptophytes, which represents one of the main lineages of multicellular eukaryotes and has contributed greatly to the change of the environment on earth in the Phanerozoic Eon. Significant progress has been made to understand phylogenetic relationships among members of this group by phylogenetic studies of morphological and molecular data over the last twenty-five years. Mesostigma viride is now regarded as among the earliest diverging unicellular organisms in streptophytes. Characeae are the sister group to land plants. Liverworts represent the first diverging lineage of land plants. Hornworts and lycophytes are extant representatives of bryophytes and vascular plants, respectively, when early land plants changed from gametophyte to sporophyte as the dominant generation in the life cycle. Equisetum, Psilotaceae, and ferns constitute the monophyletic group of monilophytes, which are sister to seed plants. Gnetales are related to conifers, not to angiosperms as previously thought. Amborella, Nymphaeales, Hydatellaceae, Illiciales, Trimeniaceae, and Austrobaileya represent the earliest diverging lineages of extant angiosperms. These phylogenetic results, together with recent progress on elucidating genetic and developmental aspects of the plant life cycle, multicellularity, and gravitropism, will facilitate evolutionary developmental studies of these key traits, which will help us to gain mechanistic understanding on how plants adapted to environmental challenges when they colonized the land during one of the major transitions in evolution of life.

A contribution to the flora of Charales in southwest Ukraine

A contribution to the flora of Charales in southwest Ukraine

Typification and circumscription ofNitella sonderi(Characeae, Charophyceae)

Nitella sonderi A.Braun in family Characeae was described in 1852, on the basis of a single specimen collected by Ferdinand von Mueller from Melbourne. This specimen was lost and not referred to again, nor illustrated. From 1857 until 1935, three other specimens of N. sonderi were examined or referred to in published literature. The species was amalgamated with the Asian species N. pseudoflabellata in 1962 and a neotype (Lewis 6) was assigned in 1972. In the year 2000, a specimen with the same collection locality and collector as the type of N. sonderi, labelled N. sonderi, was found in the National Herbarium of Victoria (Mueller, September 1852). In the present paper, I deal with the following two issues: typification of N. sonderi (i.e. is the Lewis or the Mueller specimen the most appropriate type?) and whether N. sonderi and N. pseudoflabellata are the same species. The Lewis and the Mueller specimens were compared with the protologue, and the neotype is retained. Oospores and vegetative features of N. sonderi were compared with type material of N. pseudoflabellata var. imperialis (sensu R.D.Wood) and N. sonderi is reinstated as a separate species on the basis of its vegetative morphology, dioecy and oospore morphology, and a description is given with reference to specimens from its entire range. N. sonderi is a spring and summer-growing annual of sheltered sites in temporary wetlands throughout Victoria, New South Wales, and upland south-eastern Queensland. It persists during dry times via a bank of dormant, long-lived oospores in the seed bank. Linking a good taxonomy with thorough ecological studies in this way can inform management of water resources.

An overview of Chara L. in Australia (Characeae, Charophyta)

Charophytes (family Characeae) are a cohesive group within the green algae. The genus Chara is abundant and diverse in a variety of Australian habitats. Approximately 37 taxa of Chara have been described on the basis of Australian collections. The current status of charophyte taxonomy is confused. RD Wood revised Australian charophytes in 1972 on the basis of an erroneous species concept, and charophytes are rarely identified lower than genus by ecologists and water managers. Many species were described by overseas experts in the mid-1800s, and this trend continues to the present day. Typically, species descriptions have been based on examination of few specimens, and sometimes not even fertile representatives of each species. In this study Wood’s (1972) taxonomic treatment of Australian members of the genus Chara is examined and analysed in relation to historical species concepts and more recent experimental taxonomy and oospore morphology. Thorough studies based on determination of reliable indicators of genetic incompatibility through culture studies, including oospore morphology and genetic analysis and objective analysis of fertile specimens, are now required.