Centric diatom (cells round in valve view, square to rectangular in girdle view). Often forms long filaments of cylindrical cells joined end to end, but may be found as single cells. Much narrower than filaments of Melosira. Often planktonic.
Aulacoseira, Lake Hayes, X640. Photo: Otago Regional Council & Manaaki Whenua
![[Aulacoseira], Lake Hayes, X640. Photo: Otago Regional Council & Manaaki Whenua Image](/assets/Tools-And-Resources/Identification/algae/aulacoseira__ScaleWidthWzEwMjRd.jpg)