Achlya fuegiana, a new species from Tierra del Fuego Province (Argentina)

Achlya fuegiana sp. nov., occurring on litter (floating dead leaves and twi gs) in Laguna Verde stream, in Tierra del Fuego Province (Argentina) is des cribed, illustrated and compared with similar species. The species produces principally papillate oogonia and androgynous antheridial branches. Immatu re oospheres, oogonial wall and oospores are distinctly yellowish. This Arg entine species differs from other known ones with centric-subcentric oospor es in having monoclinous, exiginous, and diclinous branches, a great number of secondary hyphae near the tips and non-functional antheridial branches. The oospores are centric-subcentric and 1-3(7) in number, and borne inside the oogonia.