Located about 2,300 miles (3,680 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.
Haleakalā National Park is an American national park located on the island of Maui in the state of Hawaii. Named after Haleakalā, a dormant volcano within its boundaries, the park covers an area of 33,265 acres, of which 24,719 acres is a wilderness area. The land was designated a national park in 1976 and its boundaries expanded in 2005.
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".
Argyroxiphium sandwicense subsp. macrocephalum, the east Maui silversword or Haleakala silversword, is a rare plant, part of the family Asteraceae. The silversword in general is referred to as ʻāhinahina in Hawaiian.
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.
Wilkesia gymnoxiphium, is a species of flowering plant in the family Asteraceae that is endemic to the island of Kauaʻi in Hawaiʻi. It is classified as endangered on the IUCN Red List. Wilkesia is one of three genera, with Argyroxiphium and Dubautia that are believed to be descendant from a single species related to the North American tarweed. The members of these three genera constitute what is called the silversword alliance, a group whose exceedingly close genetic heritage is not reflected in their exceptionally diverse morphologies.
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.
Argyroxiphium virescens was a species of flowering plant in the family Asteraceae that was last seen in 1945. It was found only in the Hawaiian Islands where it was endemic to the eastern part of Maui. Its natural habitats were subtropical or tropical moist montane forests and subtropical or tropical high-altitude shrubland. It is officially declared extinct, but in 1989 plants were discovered that appear to be hybrids between it and the Haleakalā silversword. This hybrid is known as the Pu'u 'Alaea greensword.
Dubautia arborea, the tree dubautia or Mauna Kea dubautia, is a species of flowering plant in the family Asteraceae. A member of the silversword alliance, it is endemic to the island of Hawaiʻi. It is a shrub or small tree. It is an endangered species that is threatened by feral grazing animals.
The Hawaiian tropical high shrublands are a tropical savanna ecoregion in the Hawaiian Islands.
Madieae is a tribe of flowering plants in the family Asteraceae. It is sometimes considered a subtribe of Heliantheae. Notable species include the tarweeds of the Western United States as well as the silverswords of Hawaii.
Argyroxiphium grayanum, commonly known as the greensword, is a species of flowering plant in the family Asteraceae, and a member of the silversword alliance, a group of over 50 species which are diverse in morphology and habitat but are genetically closely related.
Argyroxiphium sandwicense subsp. sandwicense, the Mauna Kea silversword, is a highly endangered flowering plant endemic to the island of Hawaiʻi of Hawaii. It is the "crown jewel" of the volcanic mountain Mauna Kea, from which it derives its English name. The Hawaiian name is ʻahinahina; it applies to silverswords more broadly. The Mauna Kea silversword was once common on the volcano, and extraordinary conservation efforts are being made to preserve the species.
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 naʻenaʻe.
Dubautia plantaginea is a rare species of flowering plant in the aster family known by the common name plantainleaf dubautia. It is endemic to Hawaii where it is the only member of the silversword alliance that is found on all six of the largest islands. Two of the three subspecies are rare and endangered. Like other Dubautia this plant is called na`ena`e.
Argyroxiphium × kai, commonly known as the Kai silversword, is a hybrid species of silversword plant in the family Asteraceae, and is a part of the silversword alliance. The name derived from the Hawaiian word "kai", which translates to "sea". It was described by David D. Keck in 1936. Argyroxiphium × kai is a natural hybrid between Argyroxiphium caliginis and Argyroxiphium grayanum, so the name Argyroxiphium calignis × grayanum can also apply, but is generally less common. It is endemic to Maui, Hawaii, where it grows between other Argyroxiphium species, primarily the two species that hybridized between each other. The population of the hybrid species is unknown, although it is likely that it may be endangered, or unstable due to invasive feral goats and pigs in its natural habitat. No conservation status has been assigned to Argyroxiphium × kai by the IUCN Red List, for it is a hybrid species, so a conservation status does not apply.
Argyroxiphium virescens × sandwicense subsp. macrocephalum, commonly known as the Pu'u 'Alaea greensword is a hybrid species of silversword plant in the family Asteraceae, and is a part of the silversword alliance. It is a hybrid between two taxons of silversword plant in the genus Argyroxiphium, being the presumably extinct Argyroxiphium virescens, and a subspecies, Argyroxiphium sandwicense subsp. macrocephalum. The hybrid species was discovered in 1989, when an individual flowered, which revealed hybridization features of two species of silversword. It is endemic to East Maui, primarily near the town of Pu’u Alaea, where it is seen growing beside other Argyroxiphium species. The population of the hybrid species is unknown, but is likely under threat of feral goats, and pigs that plague silversword plants.
