The Palanan Wilderness is a large, circular wildlife reserve encompassing the land and sea within a 45 km radius centered around the Palanan Point in Isabela Province on the northeastern coast of Luzon Island. It was set aside by the Philippine government in 1979 to protect the fast diminishing indigenous fauna and flora of the Sierra Madre Range. Aerial reconnaissance shows that the wilderness consists of a nearly continuous canopy of rain forests extending all the way from the crests of Sierra Madre Range eastwards and downwards to the Pacific Ocean and is minimally interrupted by human settlements along the alluvial plain of Palanan River and a few landing points along the coast. The flora of the Palanan Wilderness is representative of the Sierra Madre Range in northern Luzon. It is very diverse and largely undocumented. In 1961, Mr. H. GUTIERREZ of the Philippine National Herbarium collected briefly in the forested area between the towns of San Mariano and Palanan and made the only known collection of a unique monotypic Philippine fern, Podosorus angustatus. Later in 1968 the JACOBS & MENDOZA expedition to the vicinity of Dingalan and Baler South of the Palanan Wilderness made 421 collections, one fifth of which proved to be new to science. Botanically speaking, the area is at present still one of the least known regions in the country (Tan & Rojo, 1989).