Louisiana quillwort is a small, semi-aquatic, facultative evergreen plant with spirally-arranged leaves (sporophylls) arising from a globose, two-lobed corm. The pliant, hollow leaves are transversely septate and measure 2-3 mm (0.12 in.) wide and up to 40 cm (16.0 in.) long. Spore-containing structures (sporangia) are embedded in the pale, broadened bases of the leaves. Kral (1983) suggested that aquatic quillwort leaves may vary in length depending on water depth.