''Hibiscadelphus woodii'', or Wood's hau kuahiwi, is a species of

flowering plant Flowering plants are plants that bear flowers and fruits, and form the clade Angiospermae (). The term angiosperm is derived from the Ancient Greek, Greek words (; 'container, vessel') and (; 'seed'), meaning that the seeds are enclosed with ...

in the family

Malvaceae Malvaceae (), or the mallows, is a family of flowering plants estimated to contain 244 genera with 4225 known species. Well-known members of economic importance include Theobroma cacao, cacao, Cola (plant), cola, cotton, okra, Hibiscus sabdariffa, ...

endemic Endemism is the state of a species being found only in a single defined geographic location, such as an island, state, nation, country or other defined zone; organisms that are indigenous to a place are not endemic to it if they are also foun ...

Kauai Kauai (), anglicized as Kauai ( or ), is one of the main Hawaiian Islands. It has an area of 562.3 square miles (1,456.4 km2), making it the fourth-largest of the islands and the 21st-largest island in the United States. Kauai lies 73 m ...

Hawaii Hawaii ( ; ) is an island U.S. state, state of the United States, in the Pacific Ocean about southwest of the U.S. mainland. One of the two Non-contiguous United States, non-contiguous U.S. states (along with Alaska), it is the only sta ...

Description

It is a small tree, reaching a height of .

Distribution and habitat

''Hibiscadelphus woodii'' inhabits

basalt Basalt (; ) is an aphanite, aphanitic (fine-grained) extrusive igneous rock formed from the rapid cooling of low-viscosity lava rich in magnesium and iron (mafic lava) exposed at or very near the planetary surface, surface of a terrestrial ...

scree Scree is a collection of broken rock fragments at the base of a cliff or other steep rocky mass that has accumulated through periodic rockfall. Landforms associated with these materials are often called talus deposits. The term ''scree'' is ap ...

and cliff walls in ōhia lehua (''

Metrosideros polymorpha ''Metrosideros polymorpha'', the ''ōhia lehua'',; is a species of flowering evergreen tree in the Myrtus, myrtle family, Myrtaceae, that is Endemism, endemic to the six largest Hawaiian Islands, islands of Hawaii, Hawaii. It is a member of the ...

'') dominated mixed mesic forests at an elevation of in the Kalalau Valley. Associated plants include kookoolau ('' Bidens sandvicensis''), āhinahina ('' Artemisia australis''), alani ('' Melicope pallida''), naenae (''

Dubautia ''Dubautia'' or na'ena'e is a genus of flowering plant in the family Asteraceae. The genus was named after Joseph Eugène DuBaut (1796–1832), an officer in the French Navy who participated in Freycinet's expedition. The entire genus is endemi ...

'' spp.), ānaunau ('' Lepidium serra''), nehe (''

Lipochaeta ''Lipochaeta'', common name nehe, is a genus of flowering plants in the family Asteraceae that is endemic to Hawaii. Taxonomy There are difficulties regarding the classification of this genus for its affinities are uncertain. Some studies have ...

'' spp.), kolokolo kuahiwi (''

Lysimachia glutinosa ''Lysimachia'' ( ) is a genus consisting of 182 accepted species of flowering plants traditionally classified in the family Primulaceae. Based on a molecular phylogenetic study it was transferred to the family Myrsinaceae, before this family was ...

''), '' Carex meyenii'', akoko (''

Euphorbia ''Euphorbia'' is a large and diverse genus of flowering plants, commonly called spurge, in the family (biology), family Euphorbiaceae. Euphorbias range from tiny annual plants to large and long-lived trees, with perhaps the tallest being ''Eu ...

'' spp.), manono (''

Hedyotis ''Hedyotis'' (starviolet) is a genus of flowering plants in the family Rubiaceae. Many species of this genus such as ''Hedyotis biflora, H. corymbosa'' and ''H. diffusa'' are well known medicinal plants. ''Hedyotis'' is native to tropical and sub ...

'' spp.), kuluī ('' Nototrichium'' spp.), '' Panicum lineale'', kōlea (''

Myrsine ''Myrsine'' is a genus of flowering plants in the family Primulaceae. It was formerly placed in the family Myrsinaceae before this was merged into the Primulaceae. It is found nearly worldwide, primarily in tropical and subtropical areas. It co ...

'' spp.), '' Stenogyne campanulata'', '' Lobelia niihauensis'', and Mann's bluegrass ('' Poa mannii'').

Conservation

It was discovered in 1991 and described as a new species in 1995. Only four individuals were found at that time; three of those were crushed by a boulder and died between 1995 and 1998, and the last was found dead in 2011.

Pollen Pollen is a powdery substance produced by most types of flowers of seed plants for the purpose of sexual reproduction. It consists of pollen grains (highly reduced Gametophyte#Heterospory, microgametophytes), which produce male gametes (sperm ...

was found to be inviable, no fruit set was ever observed and all attempts at propagation, including by cross-pollination with '' H. distans'', failed. It was later assessed as

extinct Extinction is the termination of an organism by the death of its Endling, last member. A taxon may become Functional extinction, functionally extinct before the death of its last member if it loses the capacity to Reproduction, reproduce and ...

by the

International Union for Conservation of Nature The International Union for Conservation of Nature (IUCN) is an international organization working in the field of nature conservation and sustainable use of natural resources. Founded in 1948, IUCN has become the global authority on the stat ...

in 2016, but three individuals were rediscovered in 2019 by the

National Tropical Botanical Garden The National Tropical Botanical Garden (NTBG) is a Hawaii-based not-for-profit institution dedicated to tropical plant research, conservation, and education. It operates a network of botanical gardens and preserves in Hawaii and Florida. History ...

. The plants were growing out of a steep cliff and were found using drones.

References

woodii Endemic flora of Hawaii Biota of Kauai Trees of Hawaii Plants described in 1995 Taxonomy articles created by Polbot Critically endangered flora of the United States {{Hibisceae-stub