Algae:
- Algae are usually aquatic i.e. found in freshwater or marine water.
- Some are terrestrial and occur in moist soil, tree trunk, moist rocks and walls.
- They have a thallus like plant body i.e. not differentiated into root, stem and leaves.
- They are autotrophic.
- Reserve food material is basically starch.
- They can reproduce by any of three methods : (1) Vegetative Method, (2) Asexual Method, (3) Sexual Method
- Vascular and mechanical tissues are absent.
There are mainly 3 types of Algae :-
- Rhodophyta (Red Algae)
- Red algae are predominately marine, it is an ancient group of algae without non-flagellate cells.
- They imparts red colour due to predominance of phycobillins pigment.
- Agar- agar is obtained from Gelidium and Gracilaria which are red algae.
2. Phaeophyta (Brown Algae)
- All brown algae are usually marine and found in both tidal and subtidal regions.
- They are the highly evolved forms as the plants display highest degree of differentiation.
- Example :- Sargassum, Laminaria, Fucus etc.
3. Chlorophyta (Green Algae)
- The species included in this class are generally green in colour due to predominance of chlorophyll pigment.
- Green algae occurs in all types of moist habitats.
- Example :- Ulothrix, Chara, Ulva etc.