Sexual Compatability and Species Concept in Ectocarpus Siliculosus (Ectocarpales, Phaeophyceae) from Italy, North Carolina, Chile, and New Zealand

摘要: Several sexual strains of Ectocarpus with differing morphology originating from the Mediterranean, NW Atlantic, SE and SW Pacific were studied under culture conditions. The sporophytic gametophytic phases are anisomorphic to a varying degree both show morphological variation primarily dependent upon temperature. In crossing experiments zygotes formed in all combinations strains, however, viability hybrids between northern southern was reduced. some crosses incapable forming intact meio-sporangia but showed normal mitotic spore formation. These considered be members one species siliculosus, which is divided into geographical races or subspecies. They sexually isolated, can form hybrids, fertile on basis mito-sporangia.