- Plant body is branched, heterotrichous and filamentous and some are psedoparenchymatous.
- Plant body elongates by intercalary growth.
- In filamentous form the cells are arranged uniseriatly.
- Each cell contains chloroplast with pyrenoids.
- Reproduction take place both asexually and sexually.
- Asexual reproduction take place by plurilocular sporangia.
- Sexual reproduction take place by isogamy and anisogamy, oogamy is absent.
Family : Ectocarpaceae
- Plant body is filamentous, heterotrichous, pseudoparenchymatous.
- Sexual reproduction is isogamous.
- Alternation of generation is isomorphic.