On the enigmatic brown alga Acinetospora crinita (Ectocarpales, Fucophyceae)

The present paper reports on the study of French and Danish strains of Acin etospora crinita (Harvey) Kornmann and their responses in growth and reprod uction to various combinations of temperature and salinity. The distributio n of the species in both hemispheres may be explained by the temperature re quirements for growth and reproduction. The limit at lower latitudes in bot h hemispheres is a lethal limit, at higher latitudes it is probably a growt h and reproduction limit. Acinetospora crinita is a stenohaline species and only occurs in high salinity areas in Danish waters. This paper also discu sses the status of the genus Acinetospora, which has been considered to be a phase in the life history of some Feldmannia and Hincksia species. We con clude that there are several characters that justify independent status at the genus and species level. The large variation in reproductive patterns i s enigmatic and adds to the taxonomic confusion. In A. crinita various repr oductive structures occur: megasporangia/acinetosporangia, unilocular spora ngia (some are apomeiotic), monosporangia, plurilocular sporangia which are presumed to be gametangia, and a strain is known from the United States wi th reproduction solely by fragmentation. The combination of reproductive st ructures appears to be unique to specific strains. (C) 2001 Adac/Editions s cientifiques et medicales Elsevier SAS.