Eriodictyon altissimum is a rare species of flowering plant in the borage family known by the common name Indian Knob mountainbalm. It is endemic to San Luis Obispo County, California, where it is known from only about six occurrences in the Irish Hills on the coast and nearby Indian Knob.
Lithophragma is a genus of flowering plants containing about nine species native to western North America. These plants are known generally as woodland stars. The petals of the flowers are usually bright white with deep, long lobes or teeth. Each petal may look like three to five petals, when at closer inspection the lobes fuse into a single petal at its base. Most species reproduce via bulblets instead of seeds. L. maximum is a federally listed endangered species. Lithophragma specifically coevolved with moths of the genus Greya, who pollinate and only lay eggs on Lithophragma plants.
Castilleja grisea is a rare species of Indian paintbrush known by the common name San Clemente Island Indian paintbrush. It is endemic to San Clemente Island, one of the Channel Islands of California. San Clemente Island is owned by the US Navy so the Navy is involved in a management program to recover this species.
Lithophragma cymbalaria is a species of flowering plant in the saxifrage family known by the common name mission woodland star.
Malacothamnus clementinus is a rare species of flowering plant in the mallow family known by the common name San Clemente Island bushmallow. It is endemic to San Clemente Island, one of the Channel Islands of California, where it is known from fewer than ten occurrences in the steep, rocky seaside canyons.
Sibara filifolia, the Santa Cruz Island winged rockcress or Santa Cruz Island rockcress, is a rare species of flowering plant in the family Brassicaceae. It is endemic to the Channel Islands of California, where it is now known from a few occurrences on San Clemente Island and one population on Catalina Island.
Thysanocarpus conchuliferus is a rare species of flowering plant in the mustard family known by the common name Santa Cruz Island fringepod. It is endemic to Santa Cruz Island, one of the Channel Islands of California, where has been recently observed at only one location; some years it is totally absent.
Arabis serotina is a rare species of flowering plant in the mustard family known by the common name shale barren rockcress. It is native to eastern West Virginia and western Virginia in and around the Shenandoah Valley, where it is known from fewer than 60 populations. It is endemic to the shale barrens, a type of habitat characterized by steep slopes of bare shale, an exposed, rocky habitat type that is subject to very dry and hot conditions. Shale barrens host a number of endemics, such as Allium oxyphilum and Taenidia montana, and this rockcress is among the rarest. It is a federally listed endangered species.
Cyanea crispa is a rare species of flowering plant known by the common names crimped rollandia and Koolau Range rollandia. It is endemic to Oahu, where there are no more than fifty individuals remaining in the Koʻolau Range. It is a federally listed endangered species of the United States. Like other Cyanea it is known as haha in Hawaiian.
Cyanea shipmanii is a rare species of flowering plant in the bellflower family known by the common name Shipman's cyanea. It is endemic to the island of Hawaii, where it is known only from the windward slopes of Mauna Loa and Mauna Kea. It is a federally listed endangered species of the United States. Like other Cyanea, it is known as haha in Hawaiian.
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.
Cyrtandra subumbellata is a rare species of flowering plant in the African violet family known by the common name parasol cyrtandra. It is endemic to Hawaii, where it is known only from the Koʻolau Mountains on the island of Oahu. By 2008 there were three known populations containing 110 plants, or possibly more. It was federally listed as an endangered species in 1996. Like other Hawaiian Cyrtandra it is called ha`iwale.
Haplostachys haplostachya is a rare species of flowering plant in the mint family known by the common names honohono or Hawaiian mint. It is endemic to Hawaii, where it is now limited to the island of Hawaii and has been extirpated from Kauai and Maui. It has been on the United States' endangered species list since 1979.
Iliamna corei is a rare species of flowering plant in the mallow family known by the common name Peters Mountain mallow. It is endemic to Virginia in the United States, where it is known only from Peters Mountain in Giles County. A single occurrence remains. This is a federally listed endangered species. It is considered "one of the rarest native plants in 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.
Sanicula mariversa is a rare species of flowering plant in the family Apiaceae 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 membranacea is a rare species of flowering plant in the pink family known by the common name papery schiedea and membranous 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 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.
Erigeron maguirei is a species of flowering plant in the aster family known by the common names Maguire daisy and Maguire's fleabane. It is endemic to Utah in the United States. It is a perennial herb growing up to 28 centimetres tall. It grows from a taproot and a branching caudex. The stems are densely hairy. The inflorescence holds one to five flower heads each with several hairy, glandular phyllaries. The head has up to 20 white, pink-tinged, or pink ray florets 0.6 to 0.8 centimeters long, and many yellow disc florets at the center.
