Teilingia exigua is a species of desmid, characterized by elongated cylindrical cells with a firm cellulose cell wall. Its chloroplasts are arranged in bands along the cell sides, supporting photosynthesis. The nucleus is centrally located. Reproduction occurs through both asexual division and sexual fusion of gametes. Each cell is bilaterally symmetric with an indentation, and may have surface ornamentation. Teilingia exigua inhabits freshwater environments, thriving in nutrient-rich, sunlit waters like ponds and lakes.