Description of Aphanizomenon

Aphanizomenon is a filamentous blue-green alga (cyanobacterium). The filaments may be free-floating, solitary or in some species bound together as colonies up to an inch in length. The filaments (trichomes) are usually straight or slightly curved, rounded or narrowing at the tips, with crosswalls, no firm sheaths but sometimes a surrounding mucilagenous layer; cells may be vacuolized; sometimes with heterocysts, Gas vacuoles may be present. May cause blooms, the type species (A. flos-aquae) may cause problems in water supply reservoirs and aquaculture.