Definition of desmid in US English:



  • A single-celled freshwater alga which appears to be composed of two rigid cells with a shared nucleus. The presence of desmids is usually an indicator of unpolluted water.

    Family Desmidiaceae, division Chlorophyta (or phylum Gamophyta, kingdom Protista)

    • ‘The names themselves - diatoms, rotifers, ciliates, desmids - are both delicately Latinate or Greek-derived and appealingly concise.’
    • ‘Several desmids investigated had nuclei too large to be accommodated by the photometer aperture system and could easily have had nuclear DNA contents in excess of 4x specimens that were measured.’
    • ‘Spirogyra, stoneworts, and desmids are all members of this fresh-water group of ‘green algae’.’
    • ‘Like many other charophytes desmids have no flagella; they were lost at some point in the group's evolution.’


Mid 19th century: from modern Latin Desmidium (genus name), from Greek desmos ‘band, chain’ (because the algae are often found united in chains or masses).