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Endangered Hawaiian Plants

Approximately 1000 species of flowering plants are native to the Hawaiian Islands, 89% of which are endemic to the region.  Many of Hawaii's endemic plants have been driven to extinction due to a number of human-induced forces including deforestation, urbanization, agriculture, ranching, over-harvesting, alien species, and disease.  Some may have been common at one time or limited to a few individuals.  Presumably a few had already been driven to extinction before Western contact.  Efforts to protect these remnants include the Endangered Species Act, creation of National Wildlife Refuges, State Natural Area Reserves, private preserves (TNC), fencing to exclude mammals, invasive species control.  Propagation efforts by botanical gardens, nurseries & private citizens allow many of these rarities to survive and be appreciated.

Family Fabaceae

Sesbania tomentosa   

Kaena Point, Oahu

'OHAI

Endangered shrub formerly common on coastal dunes, and rocky outcrops.  Has silvery leaves coated with dense hairs to reflect sunlight.  Endemic to Hawaii.

 

Acacia koaia   

Ho'omaluhia, Kaneohe, Oahu

KOAI'A

Rare endangered tree of dry forests of Hawaii, Maui, Lana'i, & Moloka'i.  Distinguished from Acacia koa by its small contorted form, shorter, straighter  phyllodes, smaller pods, and extremely hard wood.  

 

Family Asteraceae

Argyroxiphium sandwicense subsp. macrocephalum   

Haleakala, Maui

HALEAKALA SILVERSWORD    'AHINAHINA

Scattered on cinder in alpine zone of Haleakala on Maui.  Narrow leaves' silver hairs reflect UV radiation and gel-filled core stores moisture.  Blooms once then dies.  Threatened with extinction due to grazing, habitat alteration, trampling of delicate root system, and loss of natural pollinators.  Endangered subspecies sandwicense occurs on Mauna Kea, Hawaii.

http://en.wikipedia.org/wiki/Argyroxiphium

http://waynesword.palomar.edu/ww0903b.htm

 

Family Goodeniaceae

Scaevola coriacea   

Waiehu dunes, Maui

DWARF NAUPAKA

Prostrate perennial of consolidated coastal dunes.  Succulent leaves 1 - 2 inches long.  Formerly found on the main islands but nearly extinct due to habitat alteration or loss.  Federally Endangered.

 

Family Rubiaceae

Gardenia brighamii  

Koko Crater BG, Oahu

NANU or NA'U

Small endangered tree from dry forests of Oahu to Hawaii.  Flower about 2 inches in diameter.  Only a few wild plants remaining but widely cultivated.

 

Family Malvaceae

Hibiscus arnottianus subsp. immaculatus

MOLOKA'I WHITE HIBISCUS    KOKI'O KE'OKE'O

Endangered and native to Moloka'i's Wailau Valley.  Has a white staminal column and shiny, toothed leaves.

 

Hibiscus clayi   

Koko Crater, Oahu

KOKI'O 'ULA

Rare endangered shrub or small tree from dry forests of eastern Kaua'i.  Flowers & leaves smaller than H. kokio.  Acuminate leaves usually have smooth margins.  Formerly known as H. newhousei.

 

 

Hibiscus brackenridgei subsp. brackenridgei  

Kapi'olani Flower Garden, Oahu

MA'O HAU HELE

Endangered shrub or small tree from dry forests of Moloka'i, Lana'i, Maui, & Hawaii.  Young stems, calices, & leaf undersides covered with short velvety hairs, flower buds lack reddish brown spots.

 

Hibiscus brackenridgei subsp. mokuleianus 

Cultivated, Waimanalo, Oahu

MA'O HAU HELE

Endangered shrub or small tree from dry forests of Kaua'i & Oahu.  Young stems & calyx covered with sharp, stinging hairs, leaves somewhat shiny, flower buds with reddish brown spots.

 

Family Campanulaceae

Brighamia rockii   

Kapi'olani Flower Garden, Oahu

  

 

ALULA    HAHA    PUA 'ALA

Endangered succulent plant inhabiting windward sea cliffs of Moloka'i & Maui.  Flowers are white.  Kaua'i's Brighamia insignis has yellow flowers.

 

Family Euphorbiaceae

Chamaesyce celastroides var. kaenana   

Ka'ena Point, Oahu

'AKOKO

Endangered shrub restricted to talus slopes at Ka'ena Point on Oahu.

 

Chamaesyce celastroides var. laehiensis   

Waiopae, Maui

EAST MAUI 'AKOKO

Endangered sprawling shrub on talus slopes of SE Maui & Lana'i.

 

Chamaesyce deppeana   

Nu'uanu Pali, Oahu

'AKOKO

Very rare sub shrub on windswept cliffs at Oahu's Nu'uanu Pali Lookout.  Thought to be extinct until its rediscovery in 1986.  Leaves lack hairs, with rounded apex & finely serrate margins.  Flowers 1.5 - 3mm wide, nearly sessile in leaf axil.

 

Family Amaranthaceae

Achyranthes splendens var. rotundata   

Ka'ena Point NAR, Oahu

ACHYRANTHES

Rare coastal shrub on dry rocky slopes & coral plains.  An endangered species occurring from Oahu to Maui.

 

Nototrichium humile   

Kapi'olani Garden, Oahu

KULU'I

Endangered shrub in dry forests, slopes, & cliffs of NW Oahu & East Maui.

 

Family Rhamnaceae

Colubrina oppositifolia   

Koko Crater BG, Oahu

KAUILA or KAUWILA

Rare endangered tree of dry & mesic forests of West Oahu & Hawaii.  Prominent glands on underside of leaves.  Extremely hard wood was used in place of metal by Hawaiians.  The name Kauila is also used for Alphitonia ponderosa, another member of this family endemic to Hawaii.

 

Family Arecaceae

Pritchardia remota   

Koko Crater, Oahu

NIHOA FAN PALM

Endemic to Nihoa Island where about 700 remain, it is now widely cultivated in gardens.  Attains height of 15 feet.  Federally listed Endangered Species.

http://www.pacsoa.org.au/palms/Pritchardia/remota.html

 

Family Portulacaceae

Portulaca molokiniensis   

UH Manoa Campus

'IHI

Rare from Molokini & two locations on Kaho'olawe.  Endemic to Hawaii.

 

Family Caryophyllaceae

Schiedea adamantis   

Koko Crater BG, Oahu
Small shrub up to 3 feet tall.  Federally listed Endangered Species.  A single wild population inhabits steep NW slopes of Leahi (Diamond Head).  A brush fire could destroy this rare plant.