The distribution and classification of the problematic Fragilaria (Virescens v.) exigua Grun.Fragilaria exiguiformis (Grun.) Lange-Bertalot: a new species or a new genus?

first_imgThe nomenclature of the taxon first recorded as Fragilaria (virescens) v. exigua by Grunow in Cleve & Moeller (1878) is examined with regard to the current botanical name, F. exiguiformis Lange-Bertalot. The distribution of this taxon in relation to pH is described from surface sediment samples collected from more than 200 soft-water lakes in both NW Europe and Antarctica. The optimum pH requirement is shown to be different in the two regions with a lower optimum (pH 5.7) for the European data set. One reason for this difference is the lack of moderately acid sites in the Antarctic data set. Another is that SEM investigation of F. exiguiformis from several localities shows that at least two taxa, characterized inter alia by presence or absence of spines, are present within this species. Lack of a rimoportula indicates that taxa in the F. exiguiformis complex should be transferred elsewhere. Also, the recognition of a non-spinose taxon within F. exiguiformis indicates that a new species description is required. Consequently and because the species complex cannot be incorporated satisfactorily into existing genera, a new genus, Stauroforma, and a new species, S. inermis are described. The species epithet is retained for the spinose taxon which becomes S. exiguiformis. Only S. inermis occurs in the Antarctic samples but both species frequently co-occur elsewhere. These two species have different ecological optima but since they cannot be easily separated by the light microscope using bright-field or phase contrast optics, their relative distributions and ecological preferences in NW European lakes remain uncertain.last_img read more

Nearly 200 schools burgled during S.Africa’s virus lockdown

first_imgSouth African authorities on Monday reported that close to 200 schools have being broken into in the first 17 days of a five-week anti-coronavirus lockdown.  Basic Education Minister Angie Motshekga said she was “horrified” after it emerged that 183 schools had been burgled since the lockdown came into effect on March 27.”It is extremely disappointing for criminals, … to randomly destroy the same infrastructure meant to provide decent spaces of learning and teaching,” said the minister in a statement. With 73 break-ins, eastern Mpumalanga province recorded the most incidents followed by Gauteng — seat of the capital Pretoria and the economic hub Johannesburg — with 55 robberies.The attacks have ranged from arson, to theft of computers, printers and even classroom chairs, according to local media reports.The rash of school attacks come just days after police minister Bheki Cele reported a dramatic fall in crime since South Africa imposed the coronavirus lockdown, crediting a ban on the sale of alcohol for the drop.In his weekly emailed note, President Cyril Ramaphosa said Monday that “it is a great indictment of our society that dozens of schools have been burgled, trashed or burnt to the ground”. Topics :last_img read more

Mikmaq author says Halifax on the right road to reconciliation

first_imgAnna Cormier APTN National NewsA respected Mi’kmaq author says Halifax is on the right road to reconciliation after the council voted to form a committee to review how it honours a controversial figure around the city.Edward Cornwallis is the former governor of the city – but maybe best known for putting a bounty on Mi’kmaq scalps.last_img