Definition of Microcystis
: a genus of unicellular blue-green algae (family Chroococcaceae) forming irregularly shaped colonies within a common gelatinous envelope and including at least one species (M. aeruginosa) that is poisonous and may become abundant and troublesome in lakes especially where much organic matter is present
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Origin and Etymology of microcystis
New Latin, from micr- + -cystis
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