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.
Auerodendron pauciflorum is a rare species of flowering plant in the family Rhamnaceae. One English language common name is turtlefat. It is endemic to Puerto Rico, where it is known from only one population in Isabela. At the time the plant was federally listed as an endangered species by the United States in 1994, only ten individual plants were known to exist. By 1997, there were 19 known specimens.
Brunfelsia portoricensis, the Puerto Rico raintree, is a species of flowering plant in the family Solanaceae. It is endemic to Puerto Rico, where it occurs in El Yunque National Forest.
Buxus vahlii, or Vahl's boxwood, is a rare species of plant in the boxwood family. It is native to Puerto Rico and St. Croix in the U.S. Virgin Islands, where it is known from no more than four populations total. It has probably never been very common, but its distribution has been reduced by deforestation and other human disturbance of its habitat. At the time it was listed as an endangered species of the United States in 1985, it was thought to be endemic to Puerto Rico. Reports that it existed in Jamaica have not been confirmed. A few individuals have been located in St. Croix, some of which are within Sandy Point National Wildlife Refuge.
Eugenia haematocarpa is a rare species of plant in the family Myrtaceae. It is endemic to Puerto Rico. It is classified as an endangered species by the U.S. Fish and Wildlife Service and there has been a plan for its recovery in place for some years. Its common names include uvillo and Luquillo Mountain stopper.
Myrcia sintenisiana is a species of flowering plant in the family Myrtaceae. It is endemic to Puerto Rico, where it is limited to the Luquillo Mountains. It occurs in El Yunque National Forest in dwarf forest habitat on wet mountain ridges. Its common name is beruquillo.
Pleodendron macranthum (chupacallos) is a rare species of tree in the family Canellaceae. It is endemic to Puerto Rico, where there are only three tiny populations remaining. Two individual plants are located in El Yunque and 8 to 10 plants remain in Río Abajo State Forest. This tree is a federally listed endangered species of the United States.
Schoepfia arenaria is an extremely rare species of hemiparasitic flowering plant in the Schoepfiaceae family. It grows as a small, multi-trunked tree. It is endemic to Puerto Rico, where it is found growing along the northern coast. A local Spanish vernacular name recorded for this tree is araña ('spider'). It has no common name in English.
Bonamia grandiflora is a rare species of flowering plant in the morning glory family known by the common names Florida lady's nightcap, Florida bonamia, and scrub morning glory. It is endemic to Central Florida, where there are about 100 known populations remaining, many of which are within the bounds of the Ocala National Forest. The plant has declined in recent decades primarily due to the development of its habitat, which is being converted to urban zones and citrus groves. This is the primary reason that the plant was federally listed as a threatened species in 1987.
Catesbaea melanocarpa is a rare species of flowering plant in the coffee family known by the common name tropical lilythorn. It is native to five Caribbean islands: Puerto Rico, St. Croix in the United States Virgin Islands, Antigua, Barbuda, and one island in Guadeloupe. The plant is threatened by habitat loss.
Clematis morefieldii is a rare species of flowering plant in the buttercup family known by the common names Morefield's leather flower and Huntsville vasevine.
Cornutia obovata is a rare species of tree in the mint family, and formerly considered a member of the verbena family. It is endemic to forested slopes in Puerto Rico, where its common names are capá jigüerilla, nigua, and palo de nigua. When it was added to the endangered species list of the United States in 1988 there were only seven individuals known to remain in the wild. By 1998 there were eight plants known. This is considered one population divided amongst a few locations in the mountain forests of the island.
Cranichis ricartii is a rare species of orchid known by the common name Puerto Rico helmet orchid. It is native to Puerto Rico, where it is known from three locations in one forest. The plant has also been seen in Guadeloupe. The plant's rarity is the main reason for its listing as an 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.
Gesneria pauciflora is a rare species of flowering plant in the family Gesneriaceae known by the common name yerba maricao de cueva. It is endemic to Puerto Rico, where there are only three populations remaining. It was federally listed as a threatened species of the United States in 1995.
Justicia cooleyi is a rare species of flowering plant in the family Acanthaceae known by the common name Cooley's water-willow. It is endemic to Florida in the United States, where it occurs in three counties. It is a federally listed endangered species.
Paysonia lyrata is a rare species of flowering plant in the family Brassicaceae known by the common name lyreleaf bladderpod. It is endemic to Alabama in the United States, where it is known from only three occurrences. It is federally listed as a threatened species.
Mitracarpus maxwelliae is a rare species of flowering plant in the coffee family known by the common name Maxwell's girdlepod. It is endemic to Puerto Rico, where it is known only from the Guánica Commonwealth Forest in Guánica. It grows in only one location in a coastal scrub forest and dwarf forest with limestone gravel substrates. Other plants in the habitat include Bucida buceras, Bursera simaruba, Exostema caribaeum, Coccoloba microstachya, Plumeria alba, and Pilosocereus royenii.
Mitracarpus polycladus is a rare species of flowering plant in the coffee family known by the common name cana gorda girdlepod. It is native to Puerto Rico, where it is known only to come from the Guánica Commonwealth Forest. It can also be found on the island of Saba. It grows in coastal scrub forest and dwarf forest with limestone gravel substrates. Other plants in the habitat include Bucida buceras, Bursera simaruba, Exostema caribaeum, Coccoloba microstachya, Plumeria alba, and Pilosocereus royenii.
Vernonia proctorii is a rare species of flowering plant in the aster family known by the common name Proctor's ironweed. It is endemic to Puerto Rico, where there are two populations. It is threatened by the destruction of its habitat. It is a federally listed endangered species of the United States.
