The long lacy and shiny fronds of this fern makes it unmistakable. This fern is a wonderful hanging epiphyte that is commonly seen growing out of other basket-forming epiphytes such as Nephrolepis acutifolia or Staghorn ferns (Platycerium spp.). So in many cases, this fern is really an epi-epiphyte! When fertile, a separate shorter specialized frond bearing the fern spores may be seen developing. The other relatives of this fern from the genus Ophioglossum (Adders tongue ferns) are small ground ferns.
This fern has a bit of a conflicted taxonomic history. It was described by Linnaeus as Ophioglossum pendulum, a name that has persisted and should persist. However, because it was earlier described by another botanist Carl Borivoj Presl as Ophioderma pendula, that name takes precedence. Modern genetic analysis though has shown that the genera Ophioderma and Ophioglossum should really be one genus, so although Ophioderma is probably the current official genus name, most botanists would probably be more comfortable calling this fern Ophioglossum pendulum.
Leaf Whispering in the Tropics 