Arthrospira is a genus of free-floating filamentous cyanobacteria characterized by cylindrical, multicellular trichomes in an open left-hand helix. There is a dietary supplement made from Arthrospira platensis and Arthrospira maxima, known as Spirulina. The maxima and platensis species were once classified in the genus Spirulina. ″Although the introduction of two separate genera [Arthrospira and Spirulina] is now generally accepted, there has been much dispute in the past and the resulting taxonomical confusion is tremendous″. ″