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Diagnostic features

Unbranched filamentous zygnematalean, having cylindrical cells with one or more green, spiralling, ribbon-like chloroplasts containing pyrenoids.  Chloroplast margins in healthy material are undulating, and the nucleus can often be seen in the cell centre, suspended in strands of cytoplasm.  A fine mucilage layer coats the filament; consequently, the strands of Spirogyra (and other zygnematalean filaments) feel "soapy" to the touch.  Conjugation is ladder-like, in which conjugation tubes form between filaments; these are traversed by the donor gamete to fertilise the receptive gamete (occasionally observed in field material).

Typical habitats

Very common around the margins of ponds, lakes and slow-flowing streams


Kingdom Plantae
Phylum Charophyta
Class Zygnemophyceae
Order Zygnematales
Family Zygnemataceae
Common name Green algae