proposed a classification for algae based on pigmentation, types of flagella, reserve food materials, thallus structure and reproduction. He published his classification in the book “The structure and reproduction of the Algae”( ). He classified algae into classes namely Chlorophyceae, Xanthophyceae, Chrysophyceae, Bacillariophyceae, Cryptophyceae, Dinophyceae, Chloromonadineae, Euglenophyceae, Phaeophyceae, Rhodophyceae, Cyanophyceae. The salient features of Chlorophyceae, Phaeophyceae and Rhodophyceae are given below.
Chlorophyceae The members are commonly called ‘Green algae’ . Most of the species are aquatic(Fresh water- Spirogyra , Marine - Ulva ). A few are terrestrial( Trentipohlia ). Variation among the shape of the chloroplast is found in members of algae.
It is cup shaped ( Chlamydomonas ), discoid ( Chara ), girdle shaped, ( Ulothrix ), reticulate ( Oedogonium ), spiral ( Spirogyra ), stellate ( Zygnema ) and plate like ( Mougeoutia ). Chlorophyll ‘a’ and Chlorophyll ‘b’ are the major photosynthetic pigments. Storage bodies called pyrenoids are present in the chloroplast and store starch. They also contain proteins.
The cell wall is made up of inner layer of cellulose and outer layer of pectin. Vegetative reproduction takes place by means of fragmentation and asexual reproduction is by the production of zoospores, aplanospores and akinetes. Sexual reproduction is present and may be isogamous, anisogamous or oogamous. Examples for this group of algae includes Chlorella, Chlamydomonas, Volvox, Spirogyra, Ulothrix, Chara and Ulva.
Phaeophyceae The members of this class are called ‘Brown algae’ . Majority of the forms are found in marine habitats. Pleurocladia is a fresh water form. The thallus is filamentous ( Ectocarpus ) frond like ( Dictyota )or may be giant kelps ( Laminaria and Macrocystis ).
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. The Pigments include Chlorophyll a, c, Carotenoids and Xanthophylls. 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. Mannitol and Laminarin are the reserve food materials.
Motile reproductive structures are