Ophioglossum pendulum is a technical scientific term that refers to a fern species commonly known as the pendant adder's tongue. Some synonyms that are used to refer to this plant species include Ophioglossum uliginosum, swamp adder's tongue, and Ophioglossum polyphyllum, many-leaved adder's tongue. Pendant adder's tongue is native to North America, and it grows in wet meadows, swamps, and poorly drained areas, especially in the eastern United States. The plant gets its common name from its drooping fronds that resemble the tongue of an adder. It's a small, evergreen plant that produces spores on the underside of its fronds, and it's used medicinally to treat a variety of ailments.