Fucales is the largest order of Phaeophyceae (brown algae), and the sistergroup to the remainder of the brown algaes. Fucales is a morphologically diverse group (Rousseau and DeReviers 1999).
The algae in the Fucales are characterized by:
Their parenchymal growth (i.e. growing in three dimensions rather than as a two-dimensional filiment), outward from an apical area at each apex.
Their reproductive organs are always contained in conceptacles, usually on the tips of the thallus (body of the aglae).
Their life cycle is almost completely diploid, with only the gametes being haploid.
Their eggs are large and non-motile, and are fertilized by small motile sperm (oogamy).
(Rousseau and DeReviers 1999)
The Fucales are found exclusively in marine habitats, in the intertidal and up into the spray zone. They are commonly found on rocky substrates. Some species grow in salt marshes and other brackish environments.
(Lee, 2008; Graham et al 2009)
The Fucales are found worldwide, but are represented by quite different taxa in different parts of the globe. In Northern waters Fucus is the the most common genus, whereas in tropical waters Sargassum predominates, Cystophora is common in Australia and Durvillea widespread in the sub-antarctic, especially southern New Zealand and Chile.
Members of the order Fucales generally live for 2-3 years. One genus, Ascophyllum, can live up to 15 years, depending on where it lives in the littoral zone: those living deeper tend to live longer than those at the top.