Ophioderma pendulum

{{Short description|Species of fern}}

{{Speciesbox

| name = Old-world adder's tongue

| image = Starr 040713-0097 Ophioderma pendulum subsp. falcatum.jpg

| image_caption =

| genus = Ophioderma (plant)

| species = pendulum

| authority = (L.) C. Presl

| synonyms =

• Ophioglossum pendulum L.

}}

Ophioderma pendulum is sometimes known as the old-world adder's-tongue. In Malaysia, it is known as daun rambu.{{citation | author = St. John, Harold | title = Ophioglossum, Rollandia, and Scaevola: Hawaiian Plant Studies | journal = Occasional Papers of Bernice P. Bishop Museum | volume = 15 | pages = 28 | date = 1940-06-26}} It is a fern in the family Ophioglossaceae, and is the type species of the genus Ophioderma. It is most noteworthy for the length of its pendant fronds, up to 14 ft 9 in (4.5 meters) in length and three inches (8 cm) wide produced at intervals along a tree-clinging rhizome.{{ cite book | editor-last= Huxley | editor-first= Anthony | date= 1992 | title= New Royal Hort. Soc. Dictionary of Gardening - Volume 3 | location= London | publisher= MacMillan Press | page= 376 }}

Ophioderma pendulum is a common epiphyte in the East Indies.