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.
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, last updated in February 2026. 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 approximate size of their native range, beginning with those with the most restricted native ranges.
ImageScientific nameChamorro name(s)OrderNative distributionConservation statusTerminalia rostrata Fosberg & FalanruwMyrtalesAsuncionLeptecophylla mariannensis (Kaneh.) C.M.WeillerEricalesAlamaganPsychotria hombroniana (Baill.) Fosberg
Psychotria hombroniana var. mariannensis (Kaneh.) Fosberg Psychotria hombroniana var. ladronica (Hosok.) Fosberg Psychotria hombroniana var. hombronianaAplokating-palaoanRubialesPsychotria hombroniana: Marianas, Caroline Islands
var. mariannensis: Alamagan var. ladronica (Hosok.) Fosberg: Rota var. hombroniana: MarianasOsmoxylon mariannense (Kaneh.) Fosberg & SachetNo known common nameApialesRotaCritically endangered (IUCN) Endangered (USFWS)Nesogenes rotensis Fosberg & D.R.HerbstNo known common nameLamialesRotaEndangered (USFWS)Derris mariannensis Hosok.FabalesRotaPsychotria rotensis Kaneh.
Psychotria rotensis var. rotensisGentianalesPsychotria rotensis: Marianas, Caroline Islands
Psychotria rotensis var. rotensis: RotaPsychotria rotensis is considered a rare plant on Guam by GPEPP (University of Guam)Croton saipanensis Hosok.EuphorbialesSaipanMucuna pacifica Hosok.FabalesSaipanPhreatia ladronica TuyamaAsparagalesSaipanHedyotis scabridifolia Kaneh.
Hedyotis scabridifolia var. scabridifolia Hedyotis scabridifolia var. stonei FosbergGentianalesHedyotis scabridifolia:Marianas
var. scabridifolia: Saipan var. stonei: Rota, GuamPogostemon guamensis Lorence & W.L.WagnerNo known common nameLamialesGuam (northern limestone cliff faces)Critically endangered (preliminarily)Tinospora homosepala DielsNo known common nameRanunculalesGuamEndangered (USFWS)Hedyotis megalantha Merr.PaudedoGentianalesGuamEndangered (USFWS)Eugenia bryanii Kaneh.No known common nameMyrtalesGuamEndangered (USFWS)Psychotria malaspinae Merr.Aplokating-palaoanGentianalesGuamEndangered (USFWS)Elatostema divaricatum (Gaudich.) FosbergRosalesGuamElatostema stenophyllum Merr.RosalesGuamDianella saffordiana Fosberg & SachetAsparagalesGuamPotamogeton marianensis Cham. & Schltdl.AlismatalesGuamPsychotria andersonii FosbergGentianalesGuamDigitaria gaudichaudii (Kunth) HenrardPoalesGuamSchleinitzia fosbergii Nevling & NiezgodaFabalesGuamAllophylus holophyllus Radlk.NgetEricalesGuamRhaphidophora guamensis P.C.BoyceAraceaeGuamTimonius nitidus (Bartl. ex DC.) Fern.-Vill.Maholoc layuGentianalesGuamSyzygium guamense ByngMyrtalesGuamBulbophyllum raulersoniae Deloso, Paulino & CootesAsparagalesGuamProposed by Deloso et al. to be listed as endangeredPeperomia mariannensis f. saipana (C.DC.) FosbergPiperalesTinian, Saipan (forma saipana) (the species Peperomia mariannensis is endemic to the Marianas and Palau)Crepidium alamaganense (S.Kobay.) T.Yukawa (synonym: Malaxis alamaganensis)AsparagalesNorthern MarianasDendrobium oblongimentum Hosok. & Fukuy.AsparagalesGuam (northern), RotaSerianthes nelsonii Merr.Håyun lågu (Guam) Trongkon guåfi (Rota)FabalesGuam, RotaEndangered (USFWS)Bulbophyllum guamense AmesSiboyas hålom tånoAsparagalesGuam, RotaThreatened (USFWS)Thelypteris gretheri (W.H.Wagner) B.C.Stone (synonym: Cyclosorus gretheri)PolypodialesGuam, RotaThelypteris guamensis (Holttum) Fosberg & Sachet (synonym: Cyclosorus guamensis)PolypodialesGuam, RotaTabernaemontana rotensis (Kaneh.) B.C.Stone (considered by POWO to be a synonym of the more widespread Tabernaemontana pandacaqui although it was determined by USFWS, using genetic analysis, to be a distinct species.Reynaud, D.T. 2012. USFWS Tabernaemontana rotensis genetics study-final report. Authen Technologies LLC, Albany. 27 pp. + appendices. https://ecos.fws.gov/docs/recovery_plan/Tabernaemontana%20rotensis_SR.pdf No known common nameGentianalesGuam, RotaThreatened (USFWS) (Tabernaemontana rotensis)Syzygium thompsoniiAtotoMyrtalesGuam, Rota, SaipanDischidia puberula Decne.GentianalesGuam, Rota, SaipanSolanum guamense Merr.Berenghenas halomtanoSolanalesMarianasEndangered (USFWS)Phyllanthus saffordii Merr.No known common nameMalpighialesMarianasEndangered (USFWS)Hedyotis laciniata Kaneh.GentianalesMarianasConsidered a rare plant on Guam by GPEPP (University of Guam)Claoxylon marianum Müll.Arg.KatotMalpighialesMarianasConsidered a rare plant on Guam by GPEPP (University of Guam)Nervilia jacksoniae Rinehart & FosbergNo known common nameAsparagalesMarianasThreatened (USFWS)Maesa walkeri Fosberg & SachetNo known common nameEricalesMarianasThreatened (USFWS)Dendrobium guamense AmesNo known common nameAsparagalesMarianasThreatened (USFWS)Trachoma guamense (Ames) Garay (synonym: Tuberolabium guamense)No known common nameAsparagalesMarianasThreatened (USFWS)Canavalia megalantha Merr.FabalesMarianasJasminum marianum DC.BanagoLamialesMarianasEugenia palumbis Merr.AgatelangMyrtalesMarianasDrypetes dolichocarpa Kaneh.(synonym: Drypetes rotensis)MwelelMalpighialesMarianasMacaranga thompsonii Merr.PenguaMalpighialesMarianasOchrosia mariannensis A.DC.
Ochrosia mariannensis var. mariannensis Ochrosia mariannensis var. crassicarpa Fosberg & FalanruwLangitiGentianalesMarianas
var. mariannensis (Marianas) var. crassicarpa (Saipan)Discocalyx megacarpa Merr.OtotEricalesMarianasDiscocalyx ladronica MezEricalesMarianasPiper guahamense C.DC.Pupúlu anitiPiperalesMarianasPiper salicinum OpizPiperalesMarianasIschaemum longisetum Merr.PoalesMarianasCyrtandra agrihanensis OhbaLamialesMarianasPremna mariannarum SchauerLamialesMarianasPremna paulobarbata H.J.LamLamialesMarianasCorchorus tiniannensis Hosok.MalvalesMarianasGrammatophyllum schmidtianum Schltr.AsparagalesMarianasBikkia longicarpa ValetonGentianalesMarianasAllophylus laetus Radlk.SapindalesMarianasTarenna sambucina var. glabra (Merr.) Fosberg & SachetSmagdaraGentianalesMarianasCallicarpa lamii Hosok.LamialesMarianas (Guam, Rota, Aguiguan, Tinian, Saipan, Alamagan, Pagan, Agrihan)Callicarpa candicans var. paucinervia (Merr.) FosbergHamlagLamialesMarianas
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. ImageScientific nameChamorro name(s)OrderNative DistributionConservation statusPhreatia thompsonii AmesAsparagalesGuam, PohnapeMeryta senfftiana VolkensApialesSaipan to Caroline IslandsPhyllanthus marianus Müll.Arg.Gaogao uchanMalpighialesMarianas to Caroline Islands (Ulithi)Psychotria mariana Bartl. ex DC.AplokatingGentianalesMarianas to Caroline Islands (Fais)Ixora triantha VolkensGuaguatGentianalesMarianas, Caroline Islands (Yap)Elaeocarpus joga Merr.YogaOxalidalesMarianas, Caroline Islands (Palau)Zeuxine fritzii Schltr.AsparagalesMarianas, Caroline Islands (Palau)Zeuxine ovata (Gaudich.) Garay & W.Kittr.AsparagalesMarianas, Caroline Islands (Palau)Artocarpus mariannensis TréculDugdugRosalesMarianas to Caroline Islands (Palau)Heritiera longipetiolata Kaneh.Ufa hålom tåno'MalvalesMarianas to Caroline Islands (Pohnpei)Endangered (USFWS)Phyllanthus mariannensis Müll.Arg. (synonym: Glochidion marianum)ChosguMalpighialesGuam and Caroline IslandsTaeniophyllum marianense Schltr.AsparagalesMarianas, Caroline IslandsHedyotis fruticulosa (Volkens) Merr.GentianalesMarianas, Caroline IslandsFicus microcarpa var. saffordii (Merr.) CornerNunu