Located about 2300 miles (3680 km) from the nearest continental shore, the Hawaiian Islands are the most isolated group of islands on the planet. The plant and animal life of the Hawaiian archipelago is the result of early, very infrequent colonizations of arriving species and the slow evolution of those species—in isolation from the rest of the world's flora and fauna—over a period of at least 5 million years. As a consequence, Hawai'i is home to a large number of endemic species. The radiation of species described by Charles Darwin in the Galapagos Islands which was critical to the formulation of his theory of evolution is far exceeded in the more isolated Hawaiian Islands.
Hawaiian hibiscus are seven species of hibiscus native to Hawaii. The yellow hibiscus is Hawaii's state flower. Most commonly grown as ornamental plants in the Hawaiian Islands are the non-native Chinese hibiscus and its numerous hybrids, though the native Hibiscus arnottianus is occasionally planted.
Argyroxiphium is a small genus of plants in the family Asteraceae. Its members are known by the common names silversword or greensword due to their long, narrow leaves and the silvery hairs on some species. The silverswords belong to a larger radiation of over 50 species, including the physically different genera Dubautia and Wilkesia. This grouping is often referred to as the silversword alliance. Botanist P. H. Raven referred to this radiation as "the best example of adaptive radiation in plants".
The silversword alliance, also known as the tarweeds, refers to an adaptive radiation of around 30 species in the composite or sunflower family, Asteraceae. The group is endemic to Hawaii, and is derived from a single immigrant to the islands. For radiating from a common ancestor at an estimated 5.2±0.8 Ma, the clade is extremely diverse, composed of trees, shrubs, subshrubs, mat-plants, cushion plants, rosette plants, and lianas.
The Alakaʻi Wilderness Preserve, popularly known as Alakaʻi Swamp, is a montane wet forest on the Hawaiian island of Kauaʻi. Although the preserve is home to alpine bogs, it is not a true swamp. It is located on a plateau near Mount Waiʻaleʻale, one of the wettest spots on Earth. Due to its unique combination of high elevation and climate, the Alakaʻi Swamp harbors a large number of endangered endemic species that are only found in this area and whose population has been dramatically declining over the last decades. It is designated as a IUCN protected area.
Argyroxiphium sandwicense, the Hawaiʻi silversword, or hinahina is a species of silversword. It is endemic to Hawaii. The two subspecies are separated by geography. Both subspecies are rare, threatened and federally protected.
Mezoneuron kauaiense is a rare shrub or small tree in the genus Mezoneuron, that is endemic to Hawaii. Common names include uhiuhi, kāwaʻu (Maui), and kea (Maui). It is threatened by invasive species, particularly feral ungulates.
Clermontia oblongifolia is a species of flowering plant in the bellflower family known by the common name Oahu clermontia. It is one of several Hawaiian lobelioids in genus Clermontia that are known as ʻoha wai. This plant is native to three of the Hawaiian Islands, where one subspecies is not uncommon but the other two are very rare and endangered.
Cyanea hamatiflora is a rare species of flowering plant in the bellflower family known by the common name wetforest cyanea. It is endemic to Hawaii, where it is known from the islands of Maui and Hawaii, and there are probably fewer than 250 plants remaining in total. It is a federally listed endangered species. Like other Cyanea it is known as haha in Hawaiian.
Cyanea lobata is a rare species of flowering plant in the bellflower family known by the common name Waihee Valley cyanea. It is endemic to Hawaii, where it is known from Lanai and Maui. It is a federally listed endangered species. Like other Cyanea it is known as haha in Hawaiian.
Cyanea mceldowneyi is a rare species of flowering plant in the bellflower family known by the common name McEldowney cyanea. It is endemic to Hawaii, where it is known only from the island of Maui. A 2007 count estimated 60 plants remaining in two populations. It was federally listed as an endangered species of the United States in 1992. Like other Cyanea it is known as haha in Hawaiian.
Dubautia imbricata is a rare species of flowering plant in the family Asteraceae known by the common names bog dubautia and imbricate dubautia. It is endemic to Hawaii where it is known only from the island of Kauai. There are four known occurrences. Like other Dubautia this plant is known as na`ena`e.
Dubautia kalalauensis is a rare species of flowering plant in the family Asteraceae. It is endemic to Hawaii where it is known only from the island of Kauai. There is only a single known population composed of 26 plants. It was federally listed as an endangered species of the United States in 2010. Like other Dubautia this plant is known as na`ena`e.
Dubautia kenwoodii, the Kalalau rim dubautia, is an "extremely rare" species of flowering plant in the family Asteraceae. It is endemic to Hawaii where it is known only from the island of Kauai. Only one plant has ever been seen: the type specimen. A part of this plant was collected in 1991 and the individual was described as a new species in 1998. It was federally listed as an endangered species of the United States in 2010. Like other Dubautia this plant is known as na`ena`e.
Dubautia latifolia is a rare species of flowering plant in the family Asteraceae known by the common name koholapehu. It is endemic to Hawaii where it is known only from the west side of the island of Kauai. Like other Dubautia this plant is called na`ena`e.
Dubautia pauciflorula is a rare species of flowering plant in the family Asteraceae known by the common name Wahiawa Bog dubautia. It is endemic to Hawaii where it is known only from the Wahiawa Mountains on the island of Kauai.
Dubautia waialealae is a rare species of flowering plant in the family Asteraceae known by the common name Wai'ale'ale dubautia. Like other Dubautia this plant is called na`ena`e.
Cyperus pennatiformis is a rare species of sedge known by the common name coastal flatsedge. It is endemic to Hawaii, where it grows on the islands of Maui, Kauai, and Laysan. It is a federally listed endangered species of the United States.
Melicope munroi is a rare species of flowering plant in the family Rutaceae known by the common names lanahale and Munro's pelea. It is endemic to Hawaii, where it is known only from the island of Lanai. It is a federally listed endangered species of the United States. Like other Hawaiian Melicope, this species is known as alani.
Tetramolopium lepidotum is a rare species of flowering plant in the family Asteraceae known by the common name Waianae Range tetramolopium. It is endemic to Hawaii, where today it is known only from the Waianae Mountains on the island of Oahu. It is threatened by habitat degradation caused by feral goats and pigs and introduced species of plants.
