Dolichospermum smithii is a filamentous cyanobacterium with cylindrical cells forming trichomes, which can be straight or curved and are often surrounded by a mucilaginous sheath. It features specialized heterocysts for nitrogen fixation and larger akinetes for survival in adverse conditions. Typically blue-green in color, this species is found in freshwater environments and plays a crucial role in primary production and nitrogen enrichment of its habitat.