Characteristics of Algae:

1. Occurrence: The algae are ubiquitous (present every where) in distribution. On the basis of occurrence, the algae may be categorized as aquatic algae, terrestrial algae and algae of remarkable habitat.
   • Aquatic Algae
   • Terrestrial Algae
   • Algae of remarkable habitat
   
2. Thallus Organisation: Thalli of algae show a range of organisation starting from unicellular form to highly organised multicellular habit where plant body is differentiated into root like holdfast, stem like stipe and leaf like lamina. Some algae called kelps show external resemblance with palm, ferns etc.
   • Unicellular Algae or Acellular Algae
   • Multicellular Algae
   
3. Reproduction: There are three types of mode of reproduction observed in various forms of algae.Vegetative • •
   • Reproduction
   • Asexual Reproduction
   •Sexual Reproduction
   
4. Embryo: Embryo stage is absent in life cycle of algae.
5. Life cycle: It is haplontic, diplontic, diplohaplontic. An alternation of generation occurs in diplohaplontic life cycle. It is of two types, isomorphic (homologous) and heteromorphic (heterologous).