Elaphoglossum serpens

Elaphoglossum serpens is a rare species of fern that grows only on Cerro de Punta, the highest mountain in Puerto Rico. The fern grows at one location, where there are 22 known specimens. It was federally listed as an endangered species of the United States in 1993. The fern was described in 1947 from specimens found at Monte Jayuya. This habitat was cleared for construction and the plant was extirpated. It was later located on Cerro de Punta. This fern is an epiphyte which grows on the trunks of the tree species Lyonia rubiginosa var. stahlii. There are only six trees that together host the 22 ferns. This mountain summit is coveted for its ideal location for communications facilities and construction of these facilities has led to destruction of part of the forest there. This fern produces a few fronds of two different types. The sterile frond is up to 19 centimeters long with a blade at the end measuring up to 8 centimeters long by 3.5 wide. The fertile frond is up to 18 centimeters ......read more on Wikipedia.