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Freshwater representatives of the red algal order Gigartinales are extremely rare, with the monotypic genus Sterrocladia being the only truly freshwater example. This alga was described in 1850 from material originating from French Guiana, and although its affinities at the ordinal and familial levels have been debated based on morphological and anatomical characteristics, its placement has not been confirmed with the assistance of molecular analyses. Here we report several collections of a freshwater red alga from Belize that share many of the characteristics of the single described species, Sterrocladia amnica, but also display some important differences. Based on microscopic analysis, our collections were distinguished from S. amnica based on thickness of the cortical layer, cell size, possession of a loose versus entire medulla and absence of reproductive nemathecia. Transmission electron microscopy confirmed a pit plug anatomy consistent with placement of the new collections in the order Gigartinales, and a new method for resin infiltration into thick cortical tissue was described. Although recent material of S. amnica was unavailable, molecular phylogenetic analyses of the rbcL and SSU rRNA gene for our new samples indicated that it was indeed a member of the Gigartinales, and that it was positioned basal to the Gigartinaceae and Phyllophoraceae clades, likely representing a novel family. The COI-5P barcode sequence showed no close matches, but the vast majority of the closest hits were to representatives of the Phyllophoraceae. Here we describe a second species within the genus Sterrocladia to accommodate our Belizean collections, Sterrocladia belizeana sp. nov., and discuss the phylogenetic affinities of this unique genus of freshwater gigartinalean red algae. We also propose a lectotype of Sterrocladia amnica based on examination of syntype materials. [ABSTRACT FROM AUTHOR]

Previous phylogenetic studies of the Rhodophyta have provided a framework for understanding red algal phylogeny, but there still exists the need for a comprehensive analysis using a broad sampling of taxa and sufficient phylogenetic information to clearly define the major lineages. In this study, we determined 48 sequences of the PSI P700 chl a apoprotein A1 ( psaA) and rbcL coding regions and established a robust red algal phylogeny to identify the major clades. The tree included most of the lineages of the Bangiophyceae (25 genera, 48 taxa). Seven well-supported lineages were identified with this analysis with the Cyanidiales having the earliest divergence and being distinct from the remaining taxa; i.e. the Porphyridiales 1–3, Bangiales, Florideophyceae, and Compsopogonales. We also analyzed data sets with fewer taxa but using seven proteins or the DNA sequence from nine genes to resolve inter-clade relationships. Based on all of these analyses, we propose that the Rhodophyta contains two new subphyla, the Cyanidiophytina with a single class, the Cyanidiophyceae, and the Rhodophytina with six classes, the Bangiophyceae, Compsopogonophyceae, Florideophyceae, Porphyridiophyceae classis nov. (which contains Porphyridium, Flintiella, and Erythrolobus), Rhodellophyceae, and Stylonematophyceae classis nov. (which contains Stylonema, Bangiopsis, Chroodactylon, Chroothece, Purpureofilum, Rhodosorus, Rhodospora, and Rufusia). We also describe a new order, Rhodellales, and a new family, Rhodellaceae (with Rhodella, Dixoniella, and Glaucosphaera). [ABSTRACT FROM AUTHOR]

Fifteen populations of the widespread freshwater red alga Batrachospermum gelatinosum (L.) De Candole were sampled throughout the geographic range in North America from central Alabama, U.S.A. (33°N) to Ellesmere Island, Nrothwest Terriotories (NWT), Canada (80°N). Analysis of ribosomal DNA internal transcribed spacer (TTS) 1 and 2 sequences yielded a parsimony tree with a large polytomy consisting of most populatins plus a branch with one Nava Scotia and two NWT populations. The nucleotide vatioation, both within the polytomy and within the branch, was small (<1%). The sequence divergence between the branch and polytomy was 3%. The lengths of the ITS 1 and 2 sequences of B. gelatinosum, 216-229 and 448-458 base pairs, respectively, fall within the very broad ranges reported for other red algae. The cluster analysis of 11 morphometric characteristics revealed three groupings of populations, partly based on geographic distribution. All tundra, eastern boreal forest, and Midwestern hemlock-hardwood populations were in one grouping, whereas the deciduous forestm coastal plain, and eastern hemlock-hardwood populations were in a second. However, one deciduous forest population from Rhode Island, U.S.A. was unassociated. There was considerable overlap in morphometric characteristics among the three groupings. Based on this fact and the relatively small nucleotide variation in ITS sequences, we conclude that B. gelatinosum is a morphologically variable and geographically wide-spread species that is a valid taxonomic entity. [ABSTRACT FROM AUTHOR]

Six populations of Batrachospermum section Setacea from North America were compared to eight type specimens using multivariate morphometrics and image analysis. From this analysis, four species in this section were distinguished worldwide: B. attrum (Hudson) Harvey [syn.B. gallaei Sirodol, B. orthostichum Skuja, B. sertularina (Bory) Bory]; B. diatyches Entwisle; B. androinvolucrum sp. nov.; and B. puiggarianum Grunow in Wittrock et Nordstedt (syn. B. angolense Welwitsch ex West et West, B. nigrescenes Welwitsch ex West et West). Two of these species were found in North America: B. attrum in California and Texas and B. androinvolucrum in British Columbia, Washington State, and Alabama. The new species, B. androinvolucrum, is distinguished by having spermatangia restricted to one-celled involucral bracts of the corpogonial branch [ABSTRACT FROM AUTHOR]

Multivariate morphometrics and image analysis were used to determine the number of well-delineated infrageneric taxa 0fSirodotia in North America. Three groupings were distinguished from 25 populations examined from Newfoundland and Quebec in the north to central Mexico in the south. These groupings were statistically related to 10 type specimens, and the following species were recognized: Sirodotia huillensis (Welwitsch ex W. et G. 3. West) Skuja (syn. S. ateleia Skuja), S. suecica Kylin (syn. S. acuminata Skuja ex Flint and S. fennica Skuja), and S. tenuilssima (Collins) Skuja ex Flint. These speies are differentiated on the basis of whorl shape and appressed; S. huillensis and S. tenuissima, truncated apex and separated), the density of spermatangia (S. huillensis, dense clusters; S. suecica and S. tenuissima, sparsely aggregated), and the mode of germination of the gonimoblast initial (S. suecica and S. tenuissima, from the nonprotuberant side of the fertilized carpogonium; S. huillensis from the protuberant side). Sirodotia huillensis was found only in the desert-chaparral, whereas S. succica and S. tenuissima occurred from southtemperate to boreal regions in cool (temperature 8-18°C), low ion (specific conductance 10-99 μ°cm[SUP-1], and mildly acidic to neutral (pH 5.7-7.3) waters. [ABSTRACT FROM AUTHOR]

Multivariate morphometrics and image analysis were used to determient he number of well-distinguished infrageneric taxa in the section Contorta of the freshwater red algal genus Batrachospermum in North America. Five groupings were distinguished from 29 populations examined from New Mexico to costa Rica. These entities were statistically related to 12 type specimens reported from or similar to North American populations. The following taxa were recognized: B. ambiguum Montagne (syn. B. bicudoi Necchi and B. basilare Fling et Skuja) B. globosporum Israelson (syn. B. cipoense Kumano et Necchi and B. Jolyi Necchi), B. intortum Jao, B. louisianae Skuja and B. Procarpum Skuja var. americanum var. nov. The new variety differs from the nominate variety in having significantly larger whorls and smaller carpogonia. Batrachospermum ambiguum, B. louisianae, and B. procarpum var. americanum occur in low ion waters (10-187 μS·cm[SUP-1]), whereas B. intortum and B. globosporum are found in h igh ion waters (260-1760 μS·cm[SUP-1]). Detailed descriptions and a key to the five taxa are given. [ABSTRACT FROM AUTHOR]

Polysiphonia subtilissima Mont. is reported for the first time from a freshwater environment. The presence of four pericentral cells, subdichotomous branching, apical trichoblasts and rhizoids arising from pericentral cells combined with a lack of cortication and reproductive cells is consistent with marine populations of this species. The range of filament length is 1.4-4.7 cm. Branch diameters are 38-76 μm and pericentral cell lengths are 58-125 μm. Batrachospermum heterocorticum sp. Nov. is distinguished primarily by a developmental change in cortical filaments from typical cylindrical cells (5.0-7.9 μm diam) in initial stages to enlarged, elliptical cells (12.9-24.1 μm diam) in mature axes. Another unique feature of this species is carpogonia with cylindrical, pedicellate trichogynes on straight carpogonial branches in mid to outer portions of lateral whorls. Other characteristics of B. heterocorticum include the following: olive-green color, 2-6 cm length, dichotomous to trichotomous fascicles in 4-7 tiers, 385-647 μm whorl diameters, 109-198 μm carpospore diameters and relatively small "chantransia" filaments. [ABSTRACT FROM AUTHOR]

In a survey of the distribution of Bangia atropurpurea (Roth) Ag. Along the north and east shorelines of the Laurentian Great Lakes, it was observed that this species was concentrated in the lower lakes. Asexual reproduction by monospore formation was the only form of reproduction in these populations. First generation germlings derived from these spores grew in a wide range of salinities from 1 to 26%, but the rate was inversely proportional to salinity. In addition, acclimation of parent plants to fresh-water or marine media prior to sporulation affected growth rates of first generation germlings placed into a series of salinities. By the second and third generation, germlings with a lineage of seawater showed a preference for the higher salinities, 19 and 26%. Plants collected in Lake Ontario exhibited no decline in photosynthetic rate as salinity was raised by 13% for 15 min. At 26% the rate was reduced by half and thylakoids were disrupted in the region of the pyreniod. On the other hand, third generation plants with a history of seawater attained maximum photosynthetic rates at 26% and contained a normal thylakoid organization. Three chromosomes were observed in these plants, which agrees with some of the previous findings for marine Bangia. Origins and taxonomic status of Bangia growing in the Great Lakes are discussed in light of these findings. [ABSTRACT FROM AUTHOR]

Chromosome number and morphology as well as reproductive seasonality were examined in Bangia populations collected from 88 sites along the British Columbia coasts. Sexual filaments were recorded at 35 sites and asexual filaments at 58. Four different types of Bangia were determined. These were characterized by reproductive state and chromosome number, as well as by their seasonality and range of distribution. A summer-fall three-chromosome sexual type occurred from approximately 50° N northward and a winter-spring four-chromosome sexual type had a northerly limit of approximately 54°N. extending to the southernmost areas of British Columbia. Two asexual types occurred, exhibiting little seasonality, six-chromosome populations at three southerly sites only. Karyograms were prepared for the four chromosomal types, assigning tentative centromere locations. Somatic chromosome pairing was reported for the first time in the Rhodophyta. [ABSTRACT FROM AUTHOR]