Tweet this page Like this page Email this page Share this page Home» Resources » Identification » Identification of algae » Freshwater algae » How to identify algae » Identification guide » Filamentous » Filaments macroscopic Individual filaments are macroscopic and easily discerned with the naked eye; could be confused with pond weed or fine grass Filaments are hollow branching tubes of cells Ulva (ex Enteromorpha) Structured as a main axis with whorls of branches at nodes.