On the conspecificity of marine and freshwaterBangiain Britain

The salinity responses of marine and freshwater Bangia have been studied in laboratory culture. Although both isolates possessed salinity tolerances which were dependent upon the salinity regimes of their original habitats, neither was restricted in its salinity tolerances to that salinity range alone. The marine isolate was able to proliferate after a single step transfer into a freshwater-based medium. Certain cells within the thallus appeared to be resistant to the sudden decrease in salinity and these developed into dwarf plantlets, following a period of dormancy. An hypothesis is proposed that Bangia occurring in freshwater is a well-adapted ecotype of the marine form, thus supporting the conspecific theory.