Hibiscadelphus distans is an extremely rare species of flowering plant in the mallow family, Malvaceae, that is endemic to the island of Kauaʻi in Hawaii. It is known as hau kuahiwi in Hawaiian, which means "upland Hibiscus tiliaceus." It is a bush or small tree with heart-shaped leaves and yellow flowers and grows at between 1,000 and 1,800 feet in the remnants of native dry forests. Despite its rarity, it is believed to be the only surviving species in the genus Hibiscadelphus which is only known from Hawaii, the other five species having recently become extinct in the wild, some being known from only a single plant.
Sapindus oahuensis is a species of tree in the soapberry family, Sapindaceae. It is endemic to Hawaii, where it is limited to Kauaʻi and Oʻahu. Its common names include Āulu, Oahu soapberry, alulu, kaulu, and lonomea.
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.
Cyperus trachysanthos is a rare species of sedge known by the common names pu`uka`a and sticky flatsedge. It is endemic to Hawaii, where it is known from Kauai and Oahu. It was known from Niihau, Molokai and Lanai, but it has been extirpated from these islands. It is a federally listed endangered species of the United States.
Exocarpos luteolus is a rare species of flowering plant in the sandalwood family known by the common names leafy ballart or heau. It is endemic to Hawaii, where it is known only from the island of Kauai. There are eight populations remaining, for a total global population of only 39 individuals. The plant was federally listed as an endangered species of the United States in 1994.
Gouania meyenii is a rare species of flowering plant known by the common name smoothfruit chewstick. It is endemic to Hawaii, where it is known only from Oahu and Kauai. It is estimated that there are between 38 and 63 individuals of this species remaining in the wild. It is a federally listed endangered species of the United States.
Isodendrion longifolium is a rare species of flowering plant in the violet family known by the common names longleaf isodendrion and aupaka. It is endemic to Hawaii, where it is known from fewer than 1000 individuals on the islands of Kauai and Oahu. It is a federally listed threatened species of the United States.
Lysimachia filifolia is a rare species of flowering plant in the Primulaceae known by the common name Wailua River yellow loosestrife. It is endemic to Hawaii, where there are two populations on Oahu and one on Kauai. It is a federally listed endangered species of the United States.
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.
Peucedanum sandwicense is a rare species of flowering plant in the carrot family known by the common name makou. It is endemic to Hawaii, where it is known from Maui, Molokai, Kauai, and Oahu. It is threatened by introduced species of plants and animals. It is a federally listed threatened species of the United States.
Plantago princeps is a rare species of flowering plant in the plantain family known by the common name ale. It is endemic to Hawaii, where it is known from the islands of Hawaii, Kauai, Oahu, Molokai, and Maui. Like other Hawaiian Plantago, it is known as kuahiwi laukahi, or laukahi kuahiwi. It is a federally listed endangered species of the United States.
Remya kauaiensis is a rare species of flowering plant in the aster family, known by the common name of Kauai remya. It is endemic to Hawaii, where it is known only from the island of Kauai. It is threatened by the degradation of its habitat. It is a federally listed endangered species of the United States.
Sanicula mariversa is a rare species of flowering plant in the carrot family known by the common name Waianae Range black-snakeroot. It is endemic to Hawaii, where it is known only from the Waianae Mountains on the island of Oahu. It is threatened by the degradation of its habitat. It is a federally listed endangered species of the United States.
Sanicula purpurea is a rare species of flowering plant in the carrot family known by the common names purple-flower black-snakeroot and purple-flowered sanicle. It is endemic to Hawaii, where it is known from Maui and from the Koolau Mountains on the island of Oahu. It is threatened by the degradation of its habitat. It was federally listed as endangered species of the United States in 1996.
Schiedea apokremnos is a rare species of flowering plant in the family Caryophyllaceae known by the common names Kauai schiedea, Na Pali Coast schiedea, and ma`oli`oli. It is endemic to Hawaii, where it is known only from the island of Kauai. It is threatened by the degradation of its habitat. It is a federally listed endangered species of the United States.
Schiedea attenuata is a rare species of flowering plant in the family Caryophyllaceae known by the common name Kalalau schiedea. It is endemic to Hawaii, where it is known only from the Kalalau Valley on the island of Kauai. It is threatened by the degradation of its habitat. It was federally listed as an endangered species of the United States in 2010.
Schiedea hookeri is a rare species of flowering plant in the family Caryophyllaceae known by the common names Hooker's schiedea and sprawling schiedea. It is endemic to Hawaii, where it is known only from the island of Oahu. It is thought to have been extirpated from Haleakalā on Maui. It is threatened by the degradation and destruction of its habitat. It was federally listed as an endangered species of the United States in 1996.
Schiedea kauaiensis is a rare species of flowering plant in the family Caryophyllaceae known by the common name Kauai schiedea. It is endemic to Hawaii, where it is known only from the island of Kauai. It is threatened by the degradation and destruction of its habitat. It was federally listed as an endangered species of the United States in 1996.
Silene lanceolata is a rare species of flowering plant in the family Caryophyllaceae known by the common names Kauai catchfly and lanceolate catchfly. It is endemic to Hawaii, where it is known only from Oahu, Molokai, and Hawaii, having been extirpated from Kauai and Lanai. It is threatened by the degradation of its habitat and it is a federally listed endangered species of the United States.
Solanum incompletum is a rare species of flowering plant in the family Solanaceae known by the common names thorny popolo and popolo ku mai. It is endemic to Hawaii, where it occurs today on the islands of Maui, Lanai, and Hawaii. It is threatened by the destruction and degradation of its habitat. It is a federally listed endangered species of the United States.
