Taxonomy, morpho-anatomy and some biological notes of 4 genera with 6 species viz., Colpomenia sinuosa (Mertens ex Roth) Derbes & Solier; lgengaria stellata (Böerg.) Boergesen; Rosenvingia fastigiata (Zanardini) Boergesen, R. orientalis (J. Agardh) Boergesen; Hydrocla thrus clathratus (C. Aoatdh) Howe including one new record of Colpomenia ecuticulata Parson of Scytosiphonales from Karachi coast is presented.
