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.
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.
Calyptranthes thomasiana is a rare species of plant in the family Myrtaceae. It is found on three islands in the Caribbean. There are fewer than 250 individuals total divided amongst the islands of Vieques in Puerto Rico, St. John in the United States Virgin Islands, and Virgin Gorda in the British Virgin Islands. It has been extirpated from the wild on Saint Thomas, U.S. Virgin Islands, where it was first described in 1855, and now only grows there in cultivation.
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.
Juglans jamaicensis, the West Indian walnut, nogal, or palo de nuez, is a species of walnut in the Juglandaceae family. It is found in Cuba, the Dominican Republic, Haiti, and Puerto Rico. It is not, in fact, native to Jamaica, as its name would suggest.
Aristida portoricensis is a rare species of grass known by the common name pelos del diablo. It is endemic to Puerto Rico, where it is known from two locations, one in a residential area of Mayagüez and one in the Sierra Bermeja. Two other known sites have been extirpated by development of the habitat. It is a federally listed endangered species of the United States.
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.
Escobaria sneedii is a rare species of cactus known by the common names Sneed's pincushion cactus and carpet foxtail cactus. It is native to the Chihuahuan Desert, where it occurs in scattered locations in New Mexico, Texas, and Chihuahua. Some plants occurring in Arizona may be included within this species. Botanical authors do not necessarily agree on the circumscription of this species. Most will agree at this point in the research, however, that there are two varieties of Escobaria sneedii, and that both are rare and endangered. The plant is popular with cactus enthusiasts and dealers because of its often petite size and tolerance for moderately cold climates. They have been overharvested from their natural habitat, the main reason why the two varieties, var. sneedii and var. leei, have been federally listed as endangered and threatened, respectively.
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.
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.
Daphnopsis hellerana is a rare species of flowering plant in the genus Daphnopsis of the family Thymelaeaceae. It is endemic to Puerto Rico, where there were only four populations remaining in 1992, with a total of 125 individuals. It was federally listed as an endangered species of the United States in 1988.
Dubautia kenwoodii is an "extremely rare" species of flowering plant in the aster family. 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.
Echinocactus horizonthalonius is a species of cactus known by several common names, including devilshead, turk's head cactus, blue barrel cactus, eagle's claw, horse maimer, horse crippler, and visnaga meloncillo. It is native to the southwestern United States and northern Mexico, where it occurs in Chihuahuan Desert and Sonoran Desert habitats, particularly on limestone substrates. One of its varieties is a federally listed endangered species of the United States.
Elaphoglossum serpens is a rare species of fern that grows only on Cerro de Punta, the highest mountain in Puerto Rico. The fern grows at one location, where there are 22 known specimens. It was federally listed as an endangered species of the United States in 1993.
Lupinus aridorum is a rare species of lupine known by the common name scrub lupine. It is endemic to Florida in the United States, where there were 10 known populations remaining in 2003. Fewer than 6000 individual plants were counted. It is threatened by the loss and degradation of its habitat. The scrub lupine is a federally listed endangered species of the United States.
Lysimachia iniki is a rare species of flowering plant in the family Primulaceae known by the common names Wailua River yellow loosestrife and Wailua River island-loosestrife. It is endemic to Hawaii, where there is only one known occurrence existing on the island of Kauai. The plant was federally listed as an endangered species of the United States in 2010.
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 from the Guánica Commonwealth Forest in Guánica. 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.
Pediocactus peeblesianus is a rare species of cactus known by the common names Navajo pincushion cactus. It is endemic to the state of Arizona in the United States. One subspecies of the plant is federally listed as an endangered species of the U.S.
Pilosocereus robinii is a species of cactus known by the common name Key tree-cactus. It is native to the Florida Keys in the United States. It also occurs in Western Cuba and the Northern Bahamas. It has been erroneously reported from Puerto Rico, the Virgin Islands, and Mexico. It is a rare species which is threatened by the loss of its habitat. It is a federally listed endangered species of the United States.
Atlantea tulita is a rare species of butterfly known by the common name Puerto Rico harlequin butterfly. This brush-footed butterfly is endemic to Puerto Rico. It is a candidate for United States federal protection as an endangered species. In 2011 a report found federal protection to be warranted, but it was precluded by other actions and it remains a candidate.
