Give an account of Phaeophyceae

Explanation

The members of this class are called .Brown algae.
(1) Majority of the forms are found in marine habitats
(ii) Pleurocladia is a fresh water form.
(iii) The thallus is filamentous (Ectocarpus) frond like (Dictyota) or may be giant kelps (Laminaria and Macrocystis).
(iv) The thallus is differentiated into leaf like photosynthetic part called fronds, a stalk like structure called stipe and a holdfast which attach thallus to the substratum.
(v) The Pigments include Chlorophyll a, c, Carotenoids and Xanthophylls.
(vi) A golden brown pigment called fucoxanthin is present and it gives shades of colour from olive green to brown to the algal members of this group. (vii) Mannitol and Laminarin are the reserve food materials. Motile reproductive structures are present.
(viii) Two laterally inserted unequal flagella are present. Among these one is whiplash and another is tinsel.
(ix) Although sexual reproduction ranges from isogamy to Oogamy, Most of the forms show Oogamous type.
(x) Alternation of generation is present (isomorphic, heteromorphic or diplontic).eg. Sargassum, Laminaria, Fucus and Dictyota