Sexual reproduction and the role of sperm attractants in monoecious species of the brown algae order fucales (fucus, hesperophycus, pelvetia, and pelvetiopsis).

Details of sexual reproduction in Fucus spiralis are reported. Slimy oogonial packets form on the outside of the receptacles held in position by hairs extending from the ostiole. Spermatozoids enter the oogonium, and fertilization takes place before zygotes are disseminated by disintegration of oogonium walls. During these events the sperm attractant fucoserratene can be detected. Fertilization in the monoecious Fucus spiralis is therefore based on the same mechanism as in dioecious members of the genus. Egg specific substances have also been detected in Californian members of the genera Fucus, Hesperophycus, Pelvetia, and Pelvetiopsis, although the biological significance of these potential sperm-attractants could not be established. The tendency towards self-fertilization in monoecious Fucales is discussed.