Critically Endangered Plants
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- A species is critically endangered when it is facing an extremely high risk of extinction in the wild in the immediate future.
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- Abies beshanzuensis
- Abies nebrodensis (Sicilian Fir)
- Abies yuanbaoshanensis
- Abies ziyuanensis
- Abronia ammophila (Tweedy's Sand Verbena)
- Abronia montecristoi
- Abutilon eremitopetalum (Hiddenpetal Indian Mallow)
- Abutilon menziesii (Ko'oloa 'ula)
- Abutilon sandwicense (Greenflower Indian Mallow)
- Acacia anegadensis (Blackbrush Wattle)
- Acacia belairioides
- Acacia mathuataensis (Tatagia)
- Acacia roigii (Erizo)
- Acaena exigua (Liliwai)
- Acalypha cuneata
- Acalypha raivavensis
- Acalypha schiedeana
- Acanthomintha duttonii (San Mateo Thorn Mint)
- Acanthomintha obovata cordata (San Diego Thorn-Mint)
- Acanthophoenix rubra (Palmiste Piquant)
- Acer buergerianum formosanum (Taiwan Trident Maple)
- Acer hainanense
- Acer leipoense
- Acer oblongum var. membranaceum
- Achyranthes mutica (Blunt Chaff Flower)
- Achyranthes splendens var. rotundata (Round Chaff Flower)
- Achyrocline glandulosa
- Achyrocline mollis
- Acmopyle sahniana
- Aconitum infectum (Arizona Monkshood)
- Actinodaphne cuspidata
- Actinodaphne lanata
- Adelobotrys panamensis
- Adenophorus periens (Pendant Kihi Fern)
- Adenophyllum wrightii (Wright's Dogweed)
- Aegiphila glomerata
- Aeschynomene pratensis (Meadow Joint-Vetch)
- Aetheolaena hypoleuca
- Aetheolaena ledifolia
- Aetheolaena pichinchensis
- Afrothismia pachyantha
- Afrothismia winkleri
- Agalinis acuta (Sandplain False Foxglove)
- Agalinis calycina (Leoncita False Foxglove)
- Agalinis navasotensis (Navasota False Foxglove)
- Agave arizonica (Arizona Century Plant)
- Aglaia densitricha
- Aglaia evansensis
- Aglaia gracilis
- Aglaia heterotricha
- Aglaia mackiana
- Aglaia malabarica
- Aglaia pleuropteris
- Aglaia unifolia
- Agrostis hendersonii (Henderson's Bentgrass)
- Agrostis rossiae (Mountain Bentgrass)
- Agrostistachys hookeri
- Albizia guillainii
- Albizia vaughanii
- Alchemilla fischeri camerunensis
- Alectryon macrococcus (Hawai'i Alectryon)
- Alectryon macrococcus Radlk. var. auwahiensis G.Linney (Hawai'i Alectryon)
- Alectryon macrococcus Radlk. var. macrococcus Radlk. (Hawai'i Alectryon)
- Alectryon macrococcus var. auwahiensis
- Alectryon macrococcus var. macrococcus
- Allium jepsonii (Jepson's Onion)
- Allium munzii (Munz's Onion)
- Allium passeyi (Passey's Onion)
- Allium shevockii (Spanish Needle Onion)
- Allophylus hispidus
- Aloe helenae
- Aloe pillansii (Bastard Quiver Tree)
- Aloe suzannae
- Alphonsea kingii
- Alsinidendron lychnoides (Kuawawaenohu)
- Alsinidendron obovatum (Waianae Range Alsinidendron)
- Alsinidendron trinerve (Three Nerved Alsinidendron)
- Alsinidendron viscosum (Climbing Alsinidendron)
- Amanoa anomala
- Amaranthus brownii (Brown's Amaranth)
- Ambrosia pumila (Dwarf Burr Ragweed)
- Amentotaxus formosana
- Amesiella monticola
- Ammophila champlainensis (Lake Champlain Beachgrass)
- Amoreuxia gonzalezii (Santa Rita Mountain Yellowshow)
- Amphitecna spathicalyx
- Amsinckia grandiflora (Large Flowered Fiddleneck)
- Amsinckia marginata
- Amsonia kearneyana (Kearney's Blue-Star)
- Amsonia tharpii (Feltleaf Bluestar)
- Andropogon benthamianus
- Angelica laurentiana (St. Lawrence Angelica)
- Aniba pedicellata
- Anisoptera curtisii
- Anisoptera megistocarpa
- Anisoptera reticulata
- Anisoptera scaphula
- Anisoptera thurifera thurifera
- Annona ecuadorensis
- Annona hystricoides
- Annona manabiensis
- Anodendron rhinosporum
- Antennaria rosea rosea (Charleston Mountain Pussytoes)
- Anthonotha leptorrhachis
- Anthurium coerulescens
- Anthurium eggersii
- Anthurium linguifolium
- Anthurium tenuicaule
- Aporusa fusiformis
- Aquilaria crassna (Agar Wood)
- Aquilegia grahamii (Graham's Columbine)
- Arabis codyi (Cody's Rockcress)
- Arabis falcatoria (Grouse Creek Rockcress)
- Arabis falcifructa (Elko Rockcress)
- Arabis georgiana (Georgia Rock-Cress)
- Arabis hirshbergiae (Cuyamaca Rockcress)
- Arabis hoffmannii (Hoffmann's Rock Cress)
- Arabis ophira (Ophir Pass Rockcress)
- Arabis pusilla (Fremont County Rockcress)
- Arabis pygmaea (Tulare County Rock Cress)
- Arabis tiehmii (Carson Range Rockcress)
- Arabis tricornuta (Rincon Mountain Rockcress)
- Aralia rex
- Araucaria angustifolia (Brazilian Monkey Puzzle Tree)
- Araucaria nemorosa
- Arctomecon humilis (Dwarf Bearclaw-Poppy)
- Arctostaphylos confertiflora (Santa Rosa Island Manzanita)
- Arctostaphylos densiflora (Vine Hill Manzanita)
- Arctostaphylos gabrielensis (San Gabriel Manzanita)
- Arctostaphylos imbricata (San Bruno Mountain Manzanita)
- Arctostaphylos klamathensis (Klamath Manzanita)
- Arctostaphylos mendocinoensis (Pygmy Manzanita)
- Arctostaphylos osoensis (Oso Manzanita)
- Arctostaphylos pacifica (Pacific Manzanita)
- Arctostaphylos pallida (Alameda Manzanita)
- Ardisia byrsonimae
- Ardisia etindensis
- Ardisia oligantha
- Ardisia schlechteri
- Arenaria livermorensis (Livermore Sandwort)
- Arenaria paludicola (Marsh Sandwort)
- Arenaria radians
- Argemone arizonica (Arizona Prickle-Poppy)
- Argyroxiphium grayanum (Hana Forest Silversword)
- Argyroxiphium kauense (Mauna Loa Silversword)
- Argyroxiphium sandwicense sandwicense (Mauna Kea Silversword)
- Arida mattturneri
- Ariocarpus bravoanus bravoanus
- Aristolochia utriformis
- Aristolochia westlandii
- Arnoglossum album (Bay County Indian-Plantain)
- Artemisia aleutica (Aleutian Wormwood)
- Asclepias prostrata (Prostrate Milkweed)
- Asclepias welshii (Welsh's Milkweed)
- Ascoglossum calopterum
- Asplenium densum (Dense Spleenwort)
- Asplenium haleakalense (Haleakala Spleenwort)
- Asplenium plenum (Ruffled Spleenwort)
- Asplenium rhomboideum (Diamond Spleenwort)
- Asplenium schizophyllum (Fringed Spleenwort)
- Asplundia clementinae
- Asplundia lutea
- Astelia waialealae (Kauai Pa'iniu)
- Aster quitensis
- Asterogyne yaracuyense
- Asteropeia amblyocarpa
- Astragalus agnicidus (Humboldt County Milkvetch)
- Astragalus albens (Cushenbury Milk-Vetch)
- Astragalus ampullarioides
- Astragalus anxius (Troubled Milkvetch)
- Astragalus applegatei (Applegate's Milk-Vetch)
- Astragalus bibullatus (Limestone Glade Milkvetch)
- Astragalus clarianus (Clara Hunt's Milk-Vetch)
- Astragalus cremnophylax (Sentry Milk-Vetch)
- Astragalus cremnophylax cremnophylax var. cremnophylax (Sentry Milk-vetch)
- Astragalus cremnophylax var. hevronii (Hevron's Milkvetch)
- Astragalus cremnophylax var. myriorrhaphis (Sentry Milkvetch)
- Astragalus desereticus (Deseret Milkvetch)
- Astragalus ertterae (Walker Pass Milkvetch)
- Astragalus hamiltonii (Hamilton's Milkvetch)
- Astragalus holmgreniorum (Holmgren Milkvetch)
- Astragalus humillimus (Mancos Milk-Vetch)
- Astragalus hypoxylus (Huachuca Mountain Milkvetch)
- Astragalus iselyi (Isely's Milkvetch)
- Astragalus jaegerianus (Lane Mountain Milkvetch)
- Astragalus loanus (Glenwood Milkvetch)
- Astragalus microcymbus (Skiff Milkvetch)
- Astragalus osterhoutii (Osterhout Milk-Vetch)
- Astragalus ravenii (Raven's Milk-Vetch)
- Astragalus riparius (Woodyroot Milkvetch)
- Astragalus sabulosus (Cisco Milkvetch)
- Astragalus schmolliae (Schmoll's Milkvetch)
- Astragalus sinuatus (Whited's Milk-Vetch)
- Astragalus tener (Slender Milk-Vetch)
- Astragalus tener titi var. titi (Coastal Dunes Milkvetch)
- Astragalus tener var. ferrisiae (Ferris Milk Vetch)
- Astragalus tener var. tener (Alkali Milk Vetch)
- Astragalus tortipes (Sleeping Ute Milkvetch)
- Astragalus tricarinatus (Triple-Ribbed Milk-Vetch)
- Astragalus webberi (Webber's Milkvetch)
- Astrocaryum minus
- Astronidium floribundum
- Astronidium inflatum
- Astronidium kasiense
- Astronidium lepidotum
- Astronidium pallidiflorum
- Astronidium saulae
- Atriplex minuscula (Lesser Saltscale)
- Atriplex nudicaulis (Baltic Saltbush)
- Atriplex parishii (Parish's Brittlescale)
- Atriplex plebeja
- Atriplex tularensis (Bakersfield Saltbush)
- Atriplex vallicola (Lost Hills Saltbush)
- Attalea crassispatha (Corossie)
- Aubregrinia taiensis
- Auerodendron pauciflorum (Turtlefat)
- Autranella congolensis
- Baccharis aretioides
- Baccharis fusca
- Baccharis malibuensis (Malibu Coyote Brush)
- Baccharis vanessae (Encinitas False Willow)
- Bactris nancibensis
- Badula crassa
- Badula platyphylla
- Badula reticulata
- Balaka macrocarpa
- Banara vanderbiltii (Vanderbilt's Palo De Ramon)
- Baptisia arachnifera (Wooly Wild Indigo)
- Barleria observatrix
- Basiphyllaea corallicola (Carter's Orchid)
- Batesimalva violacea (Purple Gay-Mallow)
- Bauhinia seleriana
- Bauhinia seminarioi
- Bazzania bhutanica
- Beccariophoenix madagascariensis (Giant Windowpane Palm)
- Begonia asympeltata
- Begonia pelargoniiflora
- Begonia salaziensis (Begonia Sauvage)
- Beilschmiedia penangiana
- Beilschmiedia preussii
- Belonophora ongensis
- Berberis harrisoniana (Harrison's Barberry)
- Berberis nilghiriensis
- Betula halophila
- Betula lenta (Virginia Round-Leaf Birch)
- Betula murrayana (Murray's Birch)
- Bhesa nitidissima
- Bhesa sinica
- Bidens hendersonensis var. oenoensis
- Bidens simplicifolia
- Bidens wiebkei (Wiebke's Beggarticks)
- Blakea granatensis
- Blennosperma bakeri (Baker's Blennosperma)
- Blephilia subnuda (Cumberland Pagoda-Plant)
- Bloomeria humilis (Dwarf Goldenstar)
- Bomarea angustifolia
- Bomarea goniocaulon
- Bomarea graminifolia
- Bomarea hartwegii
- Bomarea longipes
- Bombax insigne var. polystemon
- Bonamia menziesii (Hawai'i Lady's Nightcap)
- Bonamia ovalifolia (Bigpod Lady's Nightcap)
- Bonnetia ptariensis
- Bostrychia bocagei (Dwarf Olive Ibis)
- Botrychium acuminatum (Pointed Moonwort)
- Botrychium gallicomontanum (Frenchman's Bluff Grapefern)
- Botrychium lineare (Narrowleaf Grapefern)
- Botrychium pseudopinnatum (False Daisyleaf Moonwort)
- Botrychium tunux
- Bouteloua kayi (Kay's Grama)
- Brachystephanus kupeensis
- Braya longii (Long's Northern Rockcress)
- Braya pilosa (Hairy Rockcress)
- Brighamia insignis (Cabbage On a Stick)
- Brighamia rockii (Molokai Ohaha)
- Brodiaea pallida (Chinese Camp Brodiaea)
- Browneopsis macrofoliolata
- Brymela tutezona
- Bryopteris gaudichaudii
- Buchanania barberi
- Buddleja formosana
- Bulbophyllum filiforme
- Bulbophyllum kupense
- Burmeistera asplundii
- Burmeistera rubrosepala
- Buxus vahlii (Vahl's Boxwood)
- Byblis gigantea (Rainbow Plant)
- Byrsonima nemoralis dressleri
- Byttneria minytricha
- Cadaba insularis
- Calamagrostis cainii (Cain's Reedgrass)
- Calamagrostis perplexa (Wood Reedgrass)
- Calamus compsostachys
- Calamus obovoideus
- Calamus wailong
- Calathea dodsonii
- Calathea petersenii
- Callicarpa ampla (Cap rosa)
- Calochortus coxii (Cox's Mariposa Lily)
- Calochortus persistens (Siskiyou Mariposa Lily)
- Calochortus raichei (Cedars Mariposa Lily)
- Calochortus syntrophus
- Calochortus tiburonensis (Tiburon Mariposa Lily)
- Calochortus umpquaensis (Umpqua Mariposa Lily)
- Calochortus westonii (Shirley Meadows Mariposa Lily)
- Calodendrum eickii
- Calophyllum acutiputamen
- Calophyllum cuneifolium
- Calycanthus brockiana (Georgia Sweetshrub)
- Calycorectes schottianus
- Calyptranthes acutissima
- Calyptranthes arenicola
- Calyptranthes flavo-viridis
- Calyptranthes kiaerskovii (Kiaerskov's Lidflower)
- Calyptranthes pozasiana
- Calyptranthes uniflora
- Calystegia stebbinsii (Stebbins' False Bindweed)
- Camissonia bairdii (Baird's Evening-Primrose)
- Camissonia benitensis (San Benito Evening-Primrose)
- Camissonia confertiflora (Bunch Flower Evening Primrose)
- Camissonia exilis (Cottonwood Springs Suncup)
- Camissonia gouldii (Diamond Valley Suncup)
- Camissonia hardhamiae (Hardham's Evening-Primrose)
- Campanula robinsiae (Brooksville Bellflower)
- Campanula sharsmithiae (Sharsmith's Harebell)
- Canarium whitei
- Canavalia molokaiensis (Molokai Jack-Bean)
- Canavalia napaliensis (Makaha Valley Jackbean)
- Canavalia pubescens (Lavafield Jackbean)
- Capparis mirifica
- Capparis panamensis
- Captaincookia margaretae
- Cardamine micranthera (Small Anthered-Bittercress)
- Carex albida (White Sedge)
- Carex brysonii (Bryson's Sedge)
- Carex dutillyi (Dutilly's Sedge)
- Carex impressinervia (Impressed-Nerved Sedge)
- Carex laevivaginata (Smooth-Sheath Sedge)
- Carex lepida
- Carex lutea (Sulphur Sedge)
- Carex mckittrickensis (Guadalupe Mountain Sedge)
- Carex misandroides (Manhater Sedge)
- Carex parryana Dewey var. brevisquama F.J.Herm. (Indian Valley Sedge)
- Carex terrae-novae (Newfoundland Sedge)
- Carex tessellata
- Carex tiogana (Tioga Pass Sedge)
- Cariniana kuhlmannii
- Cariniana penduliflora
- Carlowrightia ecuadoriana
- Carpinus putoensis
- Carpodiptera mirabilis
- Carpoxylon macrospermum (Carpoxylon Palm)
- Casearia mauritiana
- Casearia williamsiana
- Cassine koordersii
- Cassipourea eketensis
- Cassipourea subcordata
- Cassipourea subsessilis
- Castanopsis catappaefolia
- Castilleja chambersii
- Castilleja christii (Christ's Indian Paintbrush)
- Castilleja chrymactis (Green Indian Paintbrush)
- Castilleja levisecta (Golden Indian Paintbrush)
- Castilleja mollis (Soft-Leaved Indian Paintbrush)
- Castilleja muelleri (Kluane Lake Indian Paintbrush)
- Castilleja ornata (Glowing Indian Paintbrush)
- Castilleja salsuginosa (Monte Neva Indian Paintbrush)
- Ceanothus ferrisiae (Coyote Ceanothus)
- Ceanothus hearstiorum (Hearst Ranch Buckbrush)
- Ceanothus masonii (Bolinas Ceanothus)
- Ceanothus ophiochilus (Vail Lake Ceanothus)
- Cenchrus agrimonioides (Agrimony Sandbur)
- Cenchrus agrimonioides var. agrimonioides (Kamanomano)
- Cenchrus agrimonioides var. laysanensis (Laysan Agrimony Sandbur)
- Centaurium sebaeoides (Hawaiian Centaury-Plant)
- Centaurodendron dracaenoides
- Centaurodendron palmiforme
- Centropogon albostellatus
- Centropogon brachysiphoniatus
- Centropogon cazaletii
- Centropogon pilalensis
- Centropogon solisii
- Centropogon uncinatus
- Ceratocentron fesselii
- Ceratozamia euryphyllidia
- Ceratozamia fusco-viridis
- Ceratozamia kuesteriana (Ceratozamia)
- Ceratozamia norstogii (Ceratozamia)
- Ceratozamia zaragozae
- Cercocarpus traskiae (Catalina Island Mountain Mahogany)
- Ceropegia decidua pretoriensis
- Ceroxylon sasaimae
- Cestrum tipocochense
- Chaetocarpus pubescens
- Chamaesyce arnottiana (Arnott's Broomspurge)
- Chamaesyce deppeana (Deppe's Broomspurge)
- Chamaesyce eleanoriae (Na Pali Sandmat)
- Chamaesyce garberi (Garber's Spurge)
- Chamaesyce halemanui (Halemanu's Broomspurge)
- Chamaesyce herbstii (Herbst's Sandmat)
- Chamaesyce remyi (Remy's Broomspurge)
- Chamaesyce remyi var. hanaleiensis (Remy's Broomspurge)
- Chamaesyce remyi var. kauaiensis (Remy's Broomspurge)
- Chamaesyce remyi var. remyi (Remy's Broomspurge)
- Chamaesyce rockii (Koolau Range Sandmat)
- Championella sarcorrhiza
- Charpentiera densiflora (Dense-Flowered Charpenttiera)
- Chassalia capitata (Bois Corail)
- Chassalia coriacea var. johnstonii
- Chassalia lanceolata lanceolata
- Chigua bernalii
- Chigua restrepoi
- Chionanthus fluminensis
- Chionanthus proctorii
- Chionanthus subsessilis
- Chionanthus tenuis
- Chlorogalum purpureum var. reductum Hoover (Cammatta Canyon Amole)
- Chloroleucon tortum (Jurema)
- Chlorophytum petrophilum
- Chodanthus montecillensis
- Chordospartium muritai
- Chorizanthe howellii (Mendocino Spineflower)
- Chorizanthe orcuttiana (San Diego Spineflower)
- Chorizanthe rectispina (One-Awned Chorizanthe)
- Chorizanthe valida (Sonoma Spineflower)
- Chromolaena frustrata (Cape Sabel Thorough-Wort)
- Chrysophyllum durifructum
- Chrysophyllum euryphyllum
- Chrysophyllum oliviforme (Satin Leaf)
- Chrysophyllum superbum
- Chrysopsis floridana (Florida Golden Aster)
- Chrysothamnus eremobius (Pintwater Rabbit-Brush)
- Cinnamomum kotoense
- Cinnamomum rivulorum
- Cinnamomum walaiwarense
- Cipocereus pusilliflorus (Cipocereus)
- Cirsium hydrophilum (Suisun Thistle)
- Cirsium rusbyi (Rusby's Thistle)
- Cirsium scapanolepis (Mountain Slope Thistle)
- Cistanthe pulchella (Mariposa Pussypaws)
- Citharexylum quitense
- Citharexylum svensonii
- Citrus taiwanica
- Claoxylon linostachys
- Clarkia franciscana (Presidio Clarkia)
- Clarkia imbricata (Vine Hill Clarkia)
- Clarkia lingulata (Merced Clarkia)
- Clarkia mosquinii (Mosquins Fairy Fan)
- Clarkia tembloriensis calientensis (Springville Clarkia)
- Clavija parvula
- Claytonia ogilviensis (Ogilvie Mountain Springbeauty)
- Cleidion lemurum
- Cleistanthus major
- Cleistanthus robustus
- Clematis morefieldii (Morefield's Leather Flower)
- Clematis socialis (Alabama Leather Flower)
- Clermontia fulva (Yellowflower Clermontia)
- Clermontia oblongifolia brevipes (Oahu Clermontia)
- Clermontia oblongifolia mauiensis (Oahu Clermontia)
- Clermontia pyrularia (Hamakua Clermontia)
- Clermontia samuelii hanaensis (Hana Clermontia)
- Clermontia samuelii samuelii (Hana Clermontia)
- Clethra coloradensis
- Clidemia ecuadorensis
- Clitoria andrei
- Cnidoscolus regina
- Coccoloba cholutecensis
- Coccoloba lindaviana
- Coccoloba retirensis
- Coccothrinax borhidiana (Borhidis Guano Palm)
- Cochlearia sessilifolia (Sessile-Leaf Scurvy-Grass)
- Cola cecidiifolia
- Cola metallica
- Cola nigerica
- Cola praeacuta
- Coleocephalocereus purpureus (Coleocephalocereus)
- Colubrina hondurensis
- Colubrina oppositifolia (Kauila)
- Columnea asteroloma
- Columnea manabiana
- Columnea poortmannii
- Combretum tenuipetiolatum
- Commidendrum spurium (False Gumwood)
- Comocladia parvifoliola
- Connarus ecuadorensis
- Connarus popenoei
- Conradina etonia (Etonia False Rosemary)
- Conradina glabra (Apalachicola False Rosemary)
- Cooperia smallii (Small's Rainlily)
- Coprosma rapensis var. benefica (Red Berry)
- Corallorhiza bentleyi (Bentleys Coralroot Orchid)
- Cordia leslieae
- Cordia rupicola (Puerto Rican Manjack)
- Cordia urticacea
- Cordia wagnerorum (Luquillo Mountain Manjack)
- Cordylanthus nidularius (Procumbent Bird's-Beak)
- Cordylanthus palmatus (Palmate-Bracted Bird's Beak)
- Coreopsis integrifolia (Chipola River Coreopsis)
- Corispermum navicula (Boat-Shaped Bugseed)
- Cornutia obovata (Palo De Nigua)
- Coryphantha vogtherriana (Coryphantha)
- Cotylelobium lewisianum
- Cotylelobium scabriusculum
- Couepia joaquinae
- Couepia scottmorii
- Couratari asterophora
- Couratari asterotricha
- Couratari prancei
- Craigia kwangsiensis
- Crassula viridis (Pricklyseed Pygmyweed)
- Crataegus distincta (Distinct Hawthorn)
- Crataegus harbisonii (Harbison Hawthorn)
- Crataegus latebrosa (Densewoods Hawthorn)
- Crataegus nananixonii (Nixons Hawthorn)
- Crataegus nitidula (Ontario Hawthorn)
- Crataegus perjucunda (Pearthorn)
- Crataegus phippsii (Phipps' Hawthorn)
- Crotalaria avonensis (Avon Park Rabbit Bells)
- Croton macrocarpus
- Croton vaughanii
- Crotonogyne impedita
- Crudia bibundina
- Cryosophila cookii
- Cryosophila grayumii
- Cryptantha clokeyi (Clokey's Cryptantha)
- Cryptantha compacta (Compact Cryptantha)
- Cryptantha crassipes (Terlingua Creek Cryptantha)
- Cryptantha crinita (Sacramento Cryptantha)
- Cryptantha incana (Tulare Cryptantha)
- Cryptantha johnstonii (Johnston's Cryptantha)
- Cryptantha mirabunda (Wonderful Cryptantha)
- Cryptantha ochroleuca (Yellowwhite Cryptantha)
- Cryptantha roosiorum (Bristle-Cone Cryptantha)
- Cryptantha semiglabra (Pipe Springs Cryptantha)
- Cryptantha shackletteana (Shacklette's Catseye)
- Cryptocarya elliptifolia
- Cryptocarya ferrarsii
- Ctenitis pallatangana
- Ctenitis squamigera (Pacific Lacefern)
- Cucurbita okeechobeensis (Okeechobee Gourd)
- Cuminia eriantha
- Cuminia fernandezia
- Cupania riopalenquensis
- Cuphea aspera (Tropical Waxweed)
- Cupressus chengiana var. jiangeensis
- Cupressus dupreziana var. dupreziana
- Cupressus goveniana (Santa Cruz Island Cypress)
- Cupressus guadalupensis var. guadalupensis
- Cuscuta dentatasquamata (Los Pinitos Dodder)
- Cuscuta mitriformis (Cochise Dodder)
- Cuscuta odontolepis (Santa Rita Mountain Dodder)
- Cuscuta plattensis (Prairie Dodder)
- Cyanea acuminata (Acuminate Cyanea)
- Cyanea asarifolia (Gingerleaf Cyanea)
- Cyanea aspleniifolia (Spleenwort-Leaved Cyanea)
- Cyanea calycina (Waianae Range Rollandia)
- Cyanea copelandii (Treetrunk Cyanea)
- Cyanea copelandii haleakalaensis (Treetrunk Cyanea)
- Cyanea crispa (Koolau Range Rollandia)
- Cyanea dolichopoda
- Cyanea dunbarii (Dunbar's Cyanea)
- Cyanea eleeleensis (Eleele Cyanea)
- Cyanea glabra (Smooth Cyanea)
- Cyanea grimesiana (Splitleaf Cyanea)
- Cyanea grimesiana grimesiana (Splitleaf Cyanea)
- Cyanea grimesiana obatae (Splitleaf Cyanea)
- Cyanea hamatiflora (Wetforest Cyanea)
- Cyanea hamatiflora carlsonii (Wetforest Cyanea)
- Cyanea hamatiflora hamatiflora (Wetforest Cyanea)
- Cyanea horrida (Prickly Cyanea)
- Cyanea kolekoleensis (Kolekole Cyanea)
- Cyanea kuhihewa
- Cyanea lanceolata lanceolata (Degener's Rollandia)
- Cyanea leptostegia (Giant Koke'e Cyanea)
- Cyanea lobata (Waihee Valley Cyanea)
- Cyanea macrostegia (Purple Cyanea)
- Cyanea mauiensis (Mceldowney's Cyanea)
- Cyanea munroi (Munro's Cyanea)
- Cyanea obtusa (Blunt-Lobe Cyanea)
- Cyanea platyphylla (Flat-Leaved Cyanea)
- Cyanea procera (Molokai Cyanea)
- Cyanea remyi (Remy's Cyanea)
- Cyanea shipmanii (Shipman's Cyanea)
- Cyanea solanacea (Popolo)
- Cyanea st-johnii (St John's Rollandia)
- Cyanea stictophylla (Kaiholena Cyanea)
- Cyanea undulata (Leechleaf Cyanea)
- Cycas beddomei (Andhra Pradesh Cycas)
- Cycas chamaoensis (Cycad)
- Cycas debaoensis (Multipinnate Cycas)
- Cycas hongheensis (Cycad)
- Cycas szechuanenis
- Cycas tansachana
- Cylindrocline commersonii
- Cymopterus goodrichii (Goodrich's Springparsley)
- Cymopterus minimus (Cedar Breaks Springparsley)
- Cymopterus panamintensis (Panamint Spring-Parsley)
- Cymopterus panamintensis Coult. & Rose var. acutifolius (Coult. & Rose) Munz (Panamint Springparsley)
- Cymopterus panamintensis Coult. and Rose var. panamintensis Coult. and Rose (Panamint Springparsley)
- Cynanchum anegadense (Caribbean Swallow-Wort)
- Cynanchum blodgettii (Blodgett's Swallow-Wort)
- Cynanchum densiflorum
- Cynanchum serpyllifolium
- Cynanchum spruceanum
- Cynanchum velutinum
- Cynometra falcata
- Cynometra filifera
- Cynometra gillmanii
- Cyperus auriculatus (Eared Flatsedge)
- Cyperus cephalanthus (Buttonbush Flatsedge)
- Cyperus fauriei (Alpine Flatsedge)
- Cyperus microcristatus
- Cyperus multifolius
- Cyperus pennatiformis (Coastal Flatsedge)
- Cyperus pennatiformis var. pennatiformis (Coastal Flatsedge)
- Cyperus trachysanthos (Sticky Flatsedge)
- Cyphophoenix nucele (Cyphophoenix)
- Cyphosperma tanga
- Cypripedium fargesii
- Cypripedium henryi (Lady Slipper Orchid)
- Cypripedium smithii
- Cypripedium wumengense
- Cypripedium yunnanense
- Cyrtandra biserrata (Double-Toothed Cyrtandra)
- Cyrtandra cyaneoides (Mapele)
- Cyrtandra dentata (Sharp-Toothed Cyrtandra)
- Cyrtandra filipes (Slender-Stalked Cyrtandra)
- Cyrtandra halawensis (Toothleaf Cyrtandra)
- Cyrtandra hematos (Singleflower Cyrtandra)
- Cyrtandra kaulantha (Waikane Valley Cyrtandra)
- Cyrtandra lydgatei (Lydgate's Cyrtandra)
- Cyrtandra munroi (Lanaihale Cyrtandra)
- Cyrtandra oenobarba (Shaggystem Cyrtandra)
- Cyrtandra oxybapha (Pohakea Gulch Cyrtandra)
- Cyrtandra paliku
- Cyrtandra polyantha (Niu Valley Cyrtandra)
- Cyrtandra rivularis (River Cyrtandra)
- Cyrtandra sandwicensis (Hairy Cyrtandra)
- Cyrtandra sessilis (Windyridge Cyrtandra)
- Cyrtandra subumbellata (Parasol Cyrtandra)
- Cyrtandra tintinnabula (Laupahoehoe Cyrtandra)
- Cyrtandra viridiflora (Green-Leaved Cyrtandra)
- Cystoathyrium chinense
- Dacrydium guillauminii
- Dactyladenia cinerea
- Dactyladenia dichotoma
- Dactyladenia eketensis
- Dactyladenia johnstonei
- Dactyladenia mannii
- Dalbergia intibucana
- Dalea bartonii (Warnocks Prairie Clover)
- Dalea tentaculoides (Gentry's Indigobush)
- Daphnopsis occulta
- Darwiniothamnus lancifolius lancifolius
- Dasphyllum lehmannii
- Debregeasia ceylanica
- Decazyx esparzae
- Deeringothamnus pulchellus (Royal False Pawpaw)
- Deeringothamnus rugelii (Rugel's False Pawpaw)
- Dehaasia acuminata
- Dehaasia chatacea
- Dehaasia pugerensis
- Delissea rhytidosperma (Kauai Delissea)
- Delissea rivularis (Plateau Delissea)
- Delissea subcordata (Heart-Shaped Delissea)
- Delissea undulata (Leechleaf Delissea)
- Delissea undulata undulata (Leechleaf Delissea)
- Delonix velutina
- Delosperma macellum
- Delphinium bakeri (Baker's Delphinium)
- Delphinium luteum (Yellow Larkspur)
- Dendrobium huoshanense
- Dendrobium officinale
- Dendrobium schuetzei
- Dendropanax cordifolius
- Dendropanax filipes
- Dendropanax grandiflorus
- Dendropanax grandis
- Dendropanax hondurensis
- Dendropanax oligodontus
- Dendroseris berteriana
- Dendroseris gigantea
- Dendroseris litoralis
- Dendroseris macrantha
- Dendroseris macrophylla
- Dendroseris marginata
- Dendroseris micrantha
- Dendroseris neriifolia
- Dendroseris pinnata
- Dendroseris pruinata
- Dendroseris regia
- Deschampsia alpina (Alpine Hair Grass)
- Descurainia torulosa (Wind River Tansymustard)
- Desmodium humifusum (Eastern Trailing Tickt Trefoil)
- Desmodium ochroleucum (Creamflower Tick-Trefoil)
- Desmopsis dolichopetala
- Dialium travancoricum
- Diastema incisum
- Dicellostyles axillaris
- Dicerandra christmanii (Yellow Scrub Balm)
- Dicerandra cornutissima (Longspurred Mint)
- Dicerandra frutescens (Scrub Balm)
- Dicerandra immaculata (Lakela's Mint)
- Dicerandra radfordiana (Radford Dicerandra)
- Dichanthelium hirstii (Hirsts' Panic Grass)
- Dichelostemma congestum (Forktooth Ookow)
- Dicliptera dodsonii
- Dicoma pretoriensis
- Dictyosperma album var. album
- Dictyosperma album var. conjugatum (Round Island Hurricane Palm)
- Diellia erecta (Asplenium-Leaved Diellia)
- Diellia laciniata (Cutleaf Island Spleenwort)
- Diellia mannii (Mann's Island Spleenwort)
- Diellia unisora (Singlesorus Island Spleenwort)
- Digitaria floridana (Florida Crabgrass)
- Digitaria gracillima (Long-Leaf Crabgrass)
- Dillenia triquetra
- Dimorphocalyx glabellus
- Dioon caputoi (Plama Real)
- Diospyros angulata (Bois D'ÉbÈne Feuilles)
- Diospyros benstonei
- Diospyros chrysophyllos (Bois D'ÉbÈne Blanc)
- Diospyros egrettarum (Bois D'ÉbÈne D'ile Aux Aigrettes Feuilles)
- Diospyros hemiteles (Bois D'ÉbÈne Feuilles)
- Diospyros katendei
- Diospyros lolinopsis
- Diospyros molissima
- Diospyros moonii
- Diospyros mun (Ebony)
- Diospyros nodosa (Bois D'ÉbÈne Feuilles)
- Diospyros rheophytica
- Diospyros vaccinioides (Small Persimmon)
- Diospyros veillonii
- Diplandrorchis sinica
- Diplazium molokaiense (Molokai Twin-Sorus Fern)
- Diplospora erythrospora
- Dipterocarpus applanatus
- Dipterocarpus baudii
- Dipterocarpus bourdilloni
- Dipterocarpus caudatus caudatus
- Dipterocarpus chartaceus
- Dipterocarpus concavus
- Dipterocarpus conformis conformis
- Dipterocarpus coriaceus
- Dipterocarpus cornutus
- Dipterocarpus costulatus
- Dipterocarpus cuspidatus
- Dipterocarpus dyeri
- Dipterocarpus elongatus
- Dipterocarpus eurynchus
- Dipterocarpus fagineus
- Dipterocarpus fusiformis
- Dipterocarpus glabrigemmatus
- Dipterocarpus glandulosus
- Dipterocarpus globosus
- Dipterocarpus gracilis
- Dipterocarpus grandiflorus
- Dipterocarpus hasseltii
- Dipterocarpus hispidus
- Dipterocarpus insignis
- Dipterocarpus kerrii
- Dipterocarpus kunstleri
- Dipterocarpus lamellatus
- Dipterocarpus littoralis
- Dipterocarpus lowii
- Dipterocarpus perakensis
- Dipterocarpus rigidus
- Dipterocarpus rotundifolius
- Dipterocarpus semivestitus
- Dipterocarpus tempehes
- Dipterocarpus turbinatus
- Dipterocarpus validus
- Ditaxis macrantha
- Dodecahema leptoceras (Slender-Horned Spineflower)
- Dombeya acutangula (Bois Bete)
- Dombeya ledermannii
- Doodia lyonii (Lyon's Hacksaw Fern)
- Doryopteris angelica (Digit Fern)
- Doryopteris takeuchii (Takeuch's Lip Fern)
- Draba brachystylis (Shortstyle Draba)
- Draba chamissonis (Cape Thompson Whitlow-Grass)
- Draba ecuadoriana
- Draba juvenilis (Tundra Whitlow-Grass)
- Draba kassii (Kass Rockcress)
- Draba kluanei (Kluane Park Whitlowgrass)
- Draba monoensis (White Mountains Draba)
- Draba paucifructa (Charleston Mountain Draba)
- Draba ramulosa (Tushar Mountain Draba)
- Draba scotteri (Scotter's Whitlowgrass)
- Draba sharsmithii (Sharsmith's Draba)
- Draba violacea
- Draba weberi (Weber's Draba)
- Dracontomelon macrocarpum
- Drepanolejeunea senticosa
- Drymophloeus samoensis
- Dryobalanops aromatica (Borneo Camphor)
- Dryobalanops fusca
- Dryobalanops keithii
- Dryopteris podosora (Kauaikinana Wood Fern)
- Dryopteris rossii (Ross' Wood Fern)
- Dryopteris tenebrosa (Na Pali-Kona Woodfern)
- Dryopteris tetrapinnata
- Drypetes riseleyi
- Drypetes tessmanniana
- Drypetes usambarica var. rugulosa
- Dubautia herbstobatae (Keaau Valley Dubautia)
- Dubautia imbricata acronaea (Imbricate Dubautia)
- Dubautia imbricata imbricata (Imbricate Dubautia)
- Dubautia kenwoodii
- Dubautia latifolia (Broad-Leaved Dubautia)
- Dubautia paleata (Na'ena'e Pua Kea)
- Dubautia pauciflorula (Wahiawa Bog Dubautia)
- Dubautia sherffiana (Waianae Range Dubautia)
- Dubautia syndetica (Wahiawa Dubautia)
- Dubautia waialealae (Waialeale Dubautia)
- Dudleya densiflora (San Gabriel Mountains Live-Forever)
- Dudleya gnoma (Munchkin Dudleya)
- Dudleya nesiotica (Santa Cruz Island Live-Forever)
- Dudleya setchellii (Santa Clara Valley Live-Forever)
- Dudleya stolonifera (Laguna Beach Live-Forever)
- Dudleya traskiae (Santa Barbara Island Live-Forever)
- Dudleya verityi (Verity's Liveforever)
- Duguetia peruviana
- Duvaliandra dioscoridis (Duvaliandra)
- Dypsis ambanjae
- Dypsis ambositrae (Ambositra Palm)
- Dypsis arenarum (Sand Palm)
- Dypsis canaliculata
- Dypsis canescens
- Dypsis ceracea (Dypsis)
- Dypsis commersoniana
- Dypsis hovomantsina (Hovomantsina Palm)
- Dypsis ifanadianae
- Dypsis intermedia
- Dypsis interrupta
- Dypsis ligulata
- Dypsis mangorensis
- Dypsis nauseosa (Dypsis)
- Dypsis nossibensis
- Dypsis oropedionis
- Dypsis ovobontsira
- Dypsis psammophila (Dypsis)
- Dypsis saintelucei
- Dypsis singularis
- Dysoxylum pachypodum
- Dysoxylum peerisi
- Echeandia texensis (Texas Craglily)
- Echinocactus grusonii (Golden Barrel Cactus)
- Echinodorus floridanus
- Egletes humifusa
- Elaeagnus conferta dendroidea
- Elaeocarpus bojeri
- Elaeocarpus gaussenii
- Elaeocarpus integrifolius
- Elaphandra retroflexa
- Elaphoglossum actinolepis
- Elaphoglossum angamarcanum
- Elaphoglossum bonapartii
- Elaphoglossum chodatii
- Elaphoglossum christii
- Elaphoglossum cladotrichium
- Elaphoglossum corazonense
- Elaphoglossum dimorphum
- Elaphoglossum gossypinum
- Elaphoglossum gracilipes
- Elaphoglossum jamesonii
- Elaphoglossum longissimum
- Elaphoglossum pellucidum (Jeweled Tonguefern)
- Elaphoglossum polytrichum
- Elaphoglossum pteropodum
- Elaphoglossum sodiroi
- Elaphoglossum sprucei
- Elaphoglossum trichophorum
- Eleocharis brachycarpa (Short-Fruited Spikerush)
- Eleocharis cylindrica (Cylinder Spike-Rush)
- Eleocharis obtusa (Wright's Spike-Rush)
- Eleocharis torticulmis (Twisted Spikerush)
- Elymus vulpinus (Rydberg's Wildrye)
- Emilia coccinea (Scarlet Tasselflower)
- Encephalartos aemulans
- Encephalartos cerinus (Waxen Palm)
- Encephalartos cupidus (Cycad)
- Encephalartos dolomiticus (Wolkberg Cycad)
- Encephalartos dyerianus (Encephalartos)
- Encephalartos equatorialis
- Encephalartos heenanii (Heenans Cycad)
- Encephalartos hirsutus
- Encephalartos inopinus (Lydenburg Cycad)
- Encephalartos laevifolius (Encephalartos)
- Encephalartos latifrons (Broadleaf Kafferbread)
- Encephalartos middelburgensis (Middleburg Cycad)
- Encephalartos msinganus
- Encephalartos munchii (Cycad)
- Encephalartos pterogonus (Toothed Cone Cycad)
- Encephalartos tegulaneus powysii
- Epilobium howellii (Yuba Pass Willowherb)
- Epithelantha micromeris polycephala (Button Cactus)
- Eragrostis fosbergii (Fosberg's Love Grass)
- Ericameria gilmanii (Whiteflower Goldenbush)
- Ericameria lignumviridis (Greenwood's Heath-Goldenrod)
- Erigeron abajoensis (Abajo Fleabane)
- Erigeron acomanus (Bluewater Fleabane)
- Erigeron adscendens
- Erigeron angustatus (Serpentine Fleabane)
- Erigeron awapensis (Awapa Fleabane)
- Erigeron bistiensis (Ojo Alamo Fleabane)
- Erigeron calvus (Bald Fleabane)
- Erigeron heliographis (Heliograph Peak Fleabane)
- Erigeron hessii (Hess' Fleabane)
- Erigeron kuschei (Chiricahua Fleabane)
- Erigeron lemmonii (Lemmon's Fleabane)
- Erigeron multiceps (Kern River Fleabane)
- Erigeron piscaticus (Fish Creek Fleabane)
- Erigeron scotteri (Scotter's Fleabane)
- Erigeron serpentinus (Serpentine Erigeron)
- Erigeron supplex (Supple Fleabane)
- Erigeron wilkenii (Dieter's Erigeron)
- Eriocaulon nigrobracteatum (Black-Bract Pipewort)
- Eriogonum ammophilum (Ibex Wild Buckwheat)
- Eriogonum argophyllum (Sulphur Hot Springs Buckwheat)
- Eriogonum brandegeei (Brandegee Wild Buckwheat)
- Eriogonum butterworthianum (Butterworth's Buckwheat)
- Eriogonum chrysops (Bitterroot Buckwheat)
- Eriogonum codium (Basalt Desert Buckwheat)
- Eriogonum cronquistii (Cronquist's Wild Buckwheat)
- Eriogonum diatomaceum (Churchill Narrows Buckwheat)
- Eriogonum eremicola (Wild Rose Canyon Buckwheat)
- Eriogonum gypsophilum (Seven River Hills Buckwheat)
- Eriogonum holmgrenii (Snake Range Buckwheat)
- Eriogonum hylophilum (Gate Canyon Wild Buckwheat)
- Eriogonum kelloggii (Red Mountain Buckwheat)
- Eriogonum mortonianum (Fredonia Wild Buckwheat)
- Eriogonum phoeniceum
- Eriogonum smithii (Smith Wild Buckwheat)
- Eriogonum soredium (Frisco Buckwheat)
- Eriogonum spectabile (Barron's Buckwheat)
- Eriogonum tiehmii (Tiehm's Buckwheat)
- Eriogonum verrucosum (Graceful Buckwheat)
- Eriophyllum latilobum (San Mateo Woolly Sunflower)
- Eryngium castrense (Great Valley Eryngo)
- Eryngium constancei (Loch Lomond Coyote-Thistle)
- Eryngium cuneifolium (Wedge-Leaved Button-Snakeroot)
- Eryngium pendletonensis (Pendleton Button-Celery)
- Eryngium phyteumae (Huachuca Mountain Coyote-Thistle)
- Erythrina perrieri
- Erythrina tahitensis (Oporavainui)
- Erythronium elegans (Coast Range Fawn Lily)
- Erythronium pluriflorum (Shuteye Peak Fawn Lily)
- Erythronium propullans (Minnesota Dwarf Trout Lily)
- Erythronium taylorii (Taylor's Fawn-Lily)
- Eschscholzia rhombipetala (Diamond-Petaled California Poppy)
- Eschweilera amplexifolia
- Eschweilera compressa
- Escobaria aguirreana
- Escobaria guadalupensis (Guadalupe Mountain Foxtail Cactus)
- Escobaria minima (Nellie Cory Cactus)
- Escobaria robbinsiorum (Cochise Pincushion Cactus)
- Eucalyptus recurva (Mongarlowe Mallee)
- Eugenia aboukirensis
- Eugenia acutissima
- Eugenia albida
- Eugenia arianae
- Eugenia bojeri
- Eugenia camptophylla
- Eugenia coyolensis
- Eugenia crassipetala
- Eugenia gageana
- Eugenia gilgii
- Eugenia guayaquilensis
- Eugenia hanoverensis
- Eugenia harrisii var. grandifolia
- Eugenia hastilis (Bois De Clous)
- Eugenia insignis
- Eugenia kameruniana
- Eugenia kellyana
- Eugenia klossii
- Eugenia lancetillae
- Eugenia polypora
- Eugenia rendlei
- Eugenia rheophytica
- Eugenia scalarinervis
- Eugenia singampattiana
- Eugenia vaughanii
- Eugenia woodburyana (Woodbury's Stopper)
- Euonymus pallidifolia
- Euphorbia alcicornis
- Euphorbia ankazobensis
- Euphorbia berorohae
- Euphorbia boinensis
- Euphorbia capmanambatoensis
- Euphorbia cylindrifolia tuberifera var. tuberifera
- Euphorbia decaryi (Euphorbia)
- Euphorbia decaryi var. robinsonii
- Euphorbia elastica
- Euphorbia francoisii (Euphorbia)
- Euphorbia francoisii var. francoisii
- Euphorbia geroldii (Euphorbia)
- Euphorbia iharanae
- Euphorbia kondoi (Euphorbia)
- Euphorbia labatii
- Euphorbia lophogona var. tenuicaulis
- Euphorbia millotii (Euphorbia)
- Euphorbia origanoides (Ascension Spurge)
- Euphorbia pachypodioides (Euphorbia)
- Euphorbia parvicyathophora
- Euphorbia quitensis
- Euphorbia razafindratsirae
- Euphorbia robivelonae
- Euphorbia rosescens
- Euphorbia stenoclada ambatofinandranae
- Euphorbia tanaensis
- Euphorbia telephioides (Telephus Spurge)
- Euphorbia tulearensis (Euphorbia)
- Eurybia saxicastellii (Rockcastle Aster)
- Eurybia spinulosa (Apalachicola Aster)
- Euryodendron excelsum
- Eutrema penlandii (Penland's Alpine Fen Mustard)
- Exocarpos luteolus (Leafy Ballart)
- Exostema orbiculatum
- Faujasiopsis reticulata (Oreille De Souris)
- Festuca hawaiiensis (Hawaiian Fescue)
- Festuca ligulata (Guadalupe Fescue)
- Ficus angladei
- Ficus faulkneriana
- Ficus lateriflora
- Fissidens hydropogon
- Fissistigma tungfangense
- Flueggea elliptica
- Flueggea neowawraea (Mehamehame)
- Forestiera hondurensis
- Frasera gypsicola (Sunnyside Green-Gentian)
- Fraxinus hondurensis
- Fremontodendron decumbens (Pine Hill Flannel Bush)
- Freziera euryoides
- Freziera forerorum
- Freziera inaequilatera
- Freziera roraimensis
- Freziera stuebelii
- Freziera subintegrifolia
- Freziera uniauriculata
- Freziera varibrateata
- Fritillaria gentneri (Gentner's Fritillaria)
- Fritillaria grayana (Gray's Fritillary)
- Fritillaria ojaiensis (Ojai Fritillary)
- Gaertnera hirtiflora (Bois Banane)
- Gaertnera longifolia
- Gaertnera truncata
- Gahnia lanaiensis (Lanai Sawsedge)
- Galactia smallii (Small's Milk Pea)
- Galeandra bicarinata (Two-Keeled Hooded Orchid)
- Galium argense (Argus Bedstraw)
- Galium grande (San Gabriel Bedstraw)
- Garcinia cadelliana
- Gardenia anapetes
- Gardenia brighamii (Native Hawaiian Gardenia Nau)
- Gardenia candida
- Gardenia mannii (Mann's Gardenia)
- Gardenia vitiensis
- Gasteranthus atratus
- Gasteranthus extinctus
- Gastonia elegans (Bois Boeuf)
- Gastonia lionnetii
- Gastonia rodriguesiana
- Gastonia sechellarum var. contracta
- Gastonia sechellarum var. curiosae
- Gastrochilus calceolaris
- Gastrodia africana
- Gazania thermalis
- Geissois ternata var. serrata
- Geniostoma clavigerum
- Genistidium dumosum (Brush-Pea)
- Gentlea molinae
- Genyorchis platybulbon
- Geranium antisanae
- Geranium arboreum (Hawaiian Red-Flowered Geranium)
- Geranium hanaense (Maui Geranium)
- Geranium kauaiense (Kauai Geranium)
- Geranium pusillum (Small-Flower Crane's-Bill)
- Gesneria scabra var. fawcettii
- Geum radiatum (Appalachian Avens)
- Gilia maculata (Little San Bernardino Mountains Gilia)
- Gilia sedifolia (Stonecrop Gilia)
- Gilia tenuis (Mussentuchit Creek Gilia)
- Gilia yorkii (Boyden Cave Gily-Flower)
- Gilmania luteola (Golden Carpet)
- Glaucocarpum suffrutescens (Shrubby Reed-Mustard)
- Gleditsia japonica
- Glochidion papenooense
- Gloeospermum boreale
- Glossopetalon texense (Texas Grease Bush)
- Glycosmis crassifolia
- Gmelina lignum-vitreum
- Gnaphalium sodiroi
- Gongrospermum philippinense
- Goniostemma punctatum
- Gonzalagunia bifida
- Gonzalagunia dodsonii
- Gonzalagunia mollis
- Gordonia curtyana
- Gouania hillebrandii (Hairyfruit Chewstick)
- Gouania meyenii (Smoothfruit Chewstick)
- Gouania vitifolia (Oahu Chewstick)
- Guarea sprucei
- Guatteria microcarpa
- Guatteria occidentalis
- Guatteria sodiroi
- Guettarda longiflora
- Guioa grandifoliola
- Guioa hospita
- Guioa palawanica
- Guioa parvifoliola
- Guioa reticulata
- Gustavia latifolia
- Gustavia longifuniculata
- Guzmania lepidota
- Guzmania poortmanii
- Guzmania striata
- Gypsophila pilosa (Moon Cactus Harrisia Martinii)
- Habenaria maitlandii
- Hackelia ibapensis (Deep Creek Stickseed)
- Hackelia venusta (Lesser Showy Stickseed)
- Halfordia papuana
- Hampea thespesioides
- Haplostachys haplostachya (Honohono)
- Harperocallis flava (Harper's Beauty)
- Hasteola robertiorum (Gulf Hammock Indian Plantain)
- Hazardia orcuttii (Orcutt's Bristleweed)
- Hedyotis degeneri Fosberg var. coprosmifolia Fosberg (Waianae Range Starviolet)
- Helianthus carnosus (Flatwoods Sunflower)
- Helianthus verticillatus (Sunflower)
- Helicia peltata
- Helicia polyosmoides
- Helicia subcordata
- Hemizonia arida (Red Rock Tarweed)
- Hemizonia halliana (Hall's Tarweed)
- Henriettea granularis
- Henriettea membranifolia (Thinleaf Camasey)
- Hernandia cubensis
- Hernandia temarii
- Herrania laciniifolia
- Hesperolinon didymocarpum (Lake County Dwarf-Flax)
- Hesperolinon drymarioides (Drymaria Dwarf-Flax)
- Hesperolinon tehamense (Tehama County Western Flax)
- Hesperomannia arborescens (Lanai Hesperomannia)
- Hesperomannia arbuscula (Maui Hesperomannia)
- Hesperomannia lydgatei (Kauai Hesperomannia)
- Heterotheca barbata (Spokane False Goldenaster)
- Heterotheca monarchensis (Sequoia False Golden-Aster)
- Heuchera alpestris (San Bernardino Mountains Alumroot)
- Hexalectris revoluta (Chisos Mountain Crested Coralroot)
- Hexapora curtisii
- Hibiscadelphus distans (Kauai Hau Kuahiwi)
- Hibiscadelphus giffardianus (Kilauea Hau Kuahiwi)
- Hibiscadelphus hualalaiensis (Hualalai Hau Kuahiwi)
- Hibiscadelphus woodii (Wood's Hau Kuahiwi)
- Hibiscus brackenridgei (Brackenridge's Rosemallow)
- Hibiscus brackenridgei molokaiana (Brackenridge's Rosemallow)
- Hibiscus clayi (Red Kauai Rosemallow Hibiscus Clayi)
- Hibiscus dasycalyx (Nacogdoches River Mallow)
- Hibiscus fragilis (Mandrinette)
- Hieracium debile
- Hieronima crassistipula
- Hildegardia populifolia
- Hoffmannseggia tenella (Slender Rush-Pea)
- Holmgrenanthe petrophila (Rock Lady)
- Holmskioldia gigas
- Holocarpha macradenia (Santa Cruz Tarplant)
- Hopea acuminata
- Hopea aequalis
- Hopea andersonii basalticola
- Hopea apiculata
- Hopea bancana
- Hopea basilanica
- Hopea beccariana
- Hopea bilitonensis
- Hopea brachyptera
- Hopea brevipetiolaris
- Hopea cagayanensis
- Hopea chinensis
- Hopea cordata
- Hopea coriacea
- Hopea depressinerva
- Hopea enicosanthoides
- Hopea erosa
- Hopea ferruginea
- Hopea glaucescens
- Hopea hainanensis
- Hopea helferi
- Hopea hongayanensis
- Hopea inexpectata
- Hopea jacobi
- Hopea johorensis
- Hopea jucunda jucunda
- Hopea jucunda modesta
- Hopea kerangasensis
- Hopea latifolia
- Hopea longirostrata
- Hopea malibato
- Hopea mengerawan
- Hopea micrantha (Hopea)
- Hopea mindanensis
- Hopea mollissima
- Hopea montana
- Hopea nervosa
- Hopea nigra
- Hopea nutans
- Hopea ovoidea
- Hopea pentanervia
- Hopea philippinensis
- Hopea plagata
- Hopea polyalthioides
- Hopea pubescens
- Hopea quisumbingiana
- Hopea reticulata
- Hopea samarensis
- Hopea sangal
- Hopea semicuneata
- Hopea siamensis
- Hopea sphaerocarpa
- Hopea sublanceolata
- Hopea sulcata
- Hopea tenuivervula
- Hopea thorelii