MORPHOMETRY OF BATRACHOSPERMUM POPULATIONS INTERMEDIATE BETWEEN B. BORYANUM AND B. ECTOCARPUM (RHODOPHYTA) 1

European Journal of Phycology

Entwisle

1995

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Type and historically important specimens of 46 species and infraspecific taxa from Batrachospermum sect. Batrachospermum were examined. Of these, 48 specimens of 33 taxa were compared using multivariate morphometrics and image analysis. Nine species from the cluster analysis and one other species are recognised: B. anatinum, B. arcuatum, B. boryanum, B. carpocontorum, B. confusum, B. fluitans, B. gelatinosum, B. heterocorticum, B. pulchrum and B. skujae. B. ectocarpum is considered to be synonymous with B. anatinum, rather than with B. boryanum or B. arcuatum as has been proposed by previous authors. The illegitimately named species B. helminthosum Sirodot (non Bory) is referable to B. confusum as are B. crouanianum and B. fruticulosum. No varieties of B. gelatinosum could be supported and numerous taxa including B. pyramidale, B. densum and B. decaisneanum are synonymised within this species. The taxa in sect. Batrachospermum are separated on the basis of whether they are monoecious or dioecious, carpogonium size, and the presence or absence of (I) spermatangia on the involucral filaments, (2) irregular cortication, (3) monosporangia, (4) well-curled fascicles and (5) secondary fascicles. Other qualitative characteristics previously used to separate taxa in this section, such as carposporophyte position, hourglass-shaped cells of the carposporophyte-bearing branch and brown cortication, were found to be too variable for use as taxonomic criteria. Additionally, the quantitative characteristics overlapped among specimens and were only useful in distinguishing B. fluitans from B. anatinum. Revised descriptions and a synoptic key of the species are provided.

Section: (9-12)mentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Morphometric analysis ofBatrachospermumsectionBatrachospermum(Batrachospermales, Rhodophyta) type specimens

Vis

European Journal of Phycology

Entwisle

1995

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“…Examination of a dioecious species is advantageous because the effects of flow on fertilization rates can be determined without self fertilization being a factor. This species is also appropriate for investigation because it is widespread in North America, Europe and Asia (summarized by Sheath & Burkholder, 1983).…”

Section: Introductionmentioning

confidence: 99%

Reproductive ecology of the freshwater red alga Batrachospermum boryanum Sirodot in a temperature headwater stream

Hambrook

1991

Hydrobiologia

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Spatial distribution and abundance of Batrachospermum boryanum gametophytes within a headwater stream in Rhode Island, USA varied considerably over a period of two years due to significant changes in dominant substrata. However, periodicity of these plants was similar each year. Juvenile gametophytes were produced by the aseasonal annual 'chantransia' stage most abundantly in September and October. Macroscopic gametophytes appeared in November and attained a peak in development during late winter and spring, correlating with relative light penetration through the surrounding tree canopy. The ratio of female to male plants increased from 1: 1 in January to 4: 1 at the end of the growing season in June during both years. Spermatangia production was continuous throughout the growth period, averaging 26 000 mm -2; mean carpogonial density was 60 mm-2. Approximately 500 spermatia were released for each carpogonium present and the mean proportion of fertilized carpogonia was 22 % . Carposporophytes typically became detached and acted as dispersal agents, settling at 0.075 cm s-'. Current velocities in the stream varied from 10 to 50 cm s-and were calculated to carry the carposporophytes 5-35 m downstream. Monospores released by 'chantransia' upright filaments also added to population spread.

“…Only 17 of these populations examined were mature, having carposporophytes. A distinct attribute observed in all the North American populations is curled branch tips (Figs 13, 16), previously noted by Sheath & Burkholder (1983). This characteristic was not reported in the type specimen (Vis et al, 1995).…”

Section: Resultsmentioning

confidence: 52%

“…1). (Hylander, 1928;Drouet, 1933;Croasdale, i935;Britton, I944;Flint, 1948Flint, , 1949Flint, , 1957aPrescott, 1962;Whifford & Schumacher, 1968, 1973Woelkerling, 1975;Sheath & Burkholder, 1983, 1985Sheath & Cole, 1993). Additional herbarium specimens from locations in California, Indiana, Nevada, New Brunswick, New Jersey, South Carolina, South Dakota, Washington and Wyoming extend the confirmed range of this species (see Appendix).…”

Section: Resultsmentioning

confidence: 86%

Distribution and systematics ofBatrachospermum(Batrachospermales, Rhodophyta) in North America. 8b. SectionBatrachospermum: previously described species excludingBatrachospermum gelatinosum

Vis

European Journal of Phycology

Cole

1996

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Sixty-two North American populations of seven previously described species belonging to Batrachospermum sect. Batrachospermum were examined and compared with appropriate type specimens using morphometrics and image analysis. All populations were similar to the respective type specimens in qualitative and quantitative characteristics, but the range of some morphological features has been extended. B. boryanum was the most abundant and widespread species, being collected in 34 stream sites from Newfoundland and British Columbia in the north to Georgia in the south. The other six species -B. anatinum, B. arcuatum, B. confusum, B. heterocorticum, B. pulchrum and B. skujae -were more localized and occurred in six or fewer streams. B. anatinum was restricted to Missouri, Arkansas and Virginia and B. arcuatum was collected in western North America from Alaska to Mexico. The distribution of B, confusum was disjunct, with populations occurring in Alberta, Quebec, Newfoundland, Maine and Missouri. B. heterocorticum was concentrated in the southern United States. This work represents only the second report of B. pulchrum; all known specimens have been collected in the Lesser Antilles of the Caribbean Islands. B. skujae was sampled in tundra streams from Manitoba and Greenland and two streams in the western coniferous forest from Colorado. No new populations were found of B. carpocontortum, which was first described from two streams in Washington state, Worldwide, many of these species have been reported from Europe, but seldom from other continents.