Micronesia is a biodiversity hotspot with an exceptionally high richness of endemic plant species, 10 times higher than that of Hawaii.  The Mariana Islands form an archipelago in the northwest of the Micronesian region.

In 2012, Craig M. Costion and David H. Lorence compiled a list of Micronesian endemic plants, and assessed that the Mariana Islands had 22 endemic plant species (16 species in the southern Mariana Islands, of which 11 were isolated to Guam, and 5 species in the northern Mariana Islands).  They concluded that there was an approximately 3% rate of endemism in the Mariana Islands (endemic species per km2), which is comparable to the rates in Hawaii (4%) and Tonga (2%) but lower than the 14% rate of endemism among all Micronesian islands.  However, the number of known Marianas endemics has greatly expanded since then with new discoveries, taxonomic revisions, and improvements in digitized databases.

List of plants endemic to the Mariana Islands 
The following list includes plants that have an endemic range only within the Mariana Islands.  "Mariana Islands" is defined in accordance with the World Geographical Scheme for Recording Plant Distributions (WGSRPD), level 3 code "MRN," and includes the following geopolitical territories:
 Guam
 Commonwealth of the Northern Marianas Islands (CNMI)
Only species, subspecies, varieties, and forms that are recognized as "accepted" by the Plants of the World Online database are included in this list; synonyms are not include.  Some synonyms are listed next to the accepted name if they are still in common use in recent botanical literature.  Subspecies are abbreviated "subs.," varieties "var.," and forms "f." after the species name.

The following list of Marianas endemic plants was compiled based on a list generated by Plants of the World Online in May 2023.  This list may not be complete and may not reflect recent changes in taxonomy.  An updated list of accepted species for a geographic area can be generated on the Plants of the World Online.

Plants are listed in order by size of their approximate native range, beginning with those with the most restricted native ranges.

Plants endemic to the Pacific islands, including the Mariana Islands 
The following list includes plants that are native to the Marianas but have a broader native range in Micronesia or the Pacific islands.  Plants with native ranges into the Asian continent are not included.

Only species or subspecies that are recognized as "accepted" by the Plants of the World Online database are included in this list (synonyms are not include).  Some synonyms are listed with the accepted name if they are still in common use in recent botanical literature.  This list is not complete and may not reflect recent changes in taxonomy.  An updated and complete list can be generated on the Plants of the World Online.

Plants are listed roughly in order by size of their native range, beginning with plants with the most restricted native ranges.

Plants formerly considered or currently proposed to be endemic to the Mariana Islands 
The following list includes select species or variants that have previously been considered endemic to the Mariana Islands, and may still be listed as such in certain publications, but are not considered to be valid species according to the Plants of the World Online database.  Also included here are species that have more recently been proposed to be distinct species or subspecies, but have not yet been accepted.

References 

 
Mariana Islands