protoctist family - any of the families of Protoctista

Charales, order Charales - small order of macroscopic fresh and brackish water algae with a distinct axis: stoneworts

stonewort - any of various submerged aquatic algae of the genus Chara having nodes with whorled filamentlike branches; usually encrusted with calcium carbonate deposits

Chara, genus Chara - green algae common in freshwater lakes of limestone districts

genus Nitella, Nitella - fragile branching stoneworts