Included here is the Pacific island group know as Yap or Yap Islands consisting of 4 continental islands. They lie within the western chain of the Caroline Islands and form part of the larger island group of Micronesia.
Of the endemic vascular plants so far recorded there are 9 species in 8 genera and 6 families but no endemic genera.
Costion, C. M. & Lorence, D. H. 2012. The Endemic Plants of Micronesia: A Geographical Checklist and Commentary. Micronesica, 43: 51-100.
Fosberg, F. R., Sachet, M. H. & Oliver, R. 1979. A Geographical Checklist of the Micronesian Dicotyledonae. Micronesica, 15: 41-295.
Fosberg, F. R. 1984. Phytogeographic comparison of Polynesia and Micronesia. In: Biogeography of the Tropical Pacific (Proceedings of a Symposium). Eds. F. J. Radovsky, P. H. Raven and H. Sohmer. Bishop Museum Special Publication No. 72.